High peak power and continuous wave tunable inalgan laser diodes and applications thereof

Abstract

Laser diodes, multijunction laser diodes, and laser diode arrays having a high peak power and that are continuously tunable are disclosed. The laser diodes are based on tire InAlGaN material system. The laser diodes have utility in a number of applications including quantum computing, quantum sensing, aerospace, defense, navigation and transportation, medicine and life sciences, industry and manufacturing, commercial and consumer apparatus, and in under underwater systems.

Description

[0001] Attorney Docket No.: 61ZD-000510PC-407084

[0002] January 27, 2026

[0003] PCT INTERNATIONAL PATENT APPLICATION

[0004] FOR

[0005] HIGH PEAK POWER AND CONTINUOUS WAVE TUNABLE INALGAN LASER DIODES AND APPLICATIONS THEREOF

[0006] BY

[0007] JOSHUA DAVID BROWN, RYAN ANDERSON, SEUNGGEUN LEE,

[0008] BRAD SISKAVICH, IAN MANN, AND JIM HADENAttorney Docket No.: 61ZD-000510PC-407084

[0009] January 27, 2026 HIGH PEAK POWER AND CONTINUOUS WAVE TUNABLE INALGAN LASER DIODES AND APPLICATIONS THEREOF

[0010]

[0001] This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application No. 63 / 750,274 filed on January 27, 2025, U.S. Provisional Application No. 63 / 750,272 filed on January 27, 2025, and U.S. Provisional Application No. 63 / 750,271 filed on January 27, 2025, each of which is incorporated by reference in its entirety.

[0011] FIELD

[0012]

[0002] The present disclosure relates to laser diodes, multijunction laser diodes, and laser diode arrays having a high peak power and that are continuously tunable over a useful wavelength range. The laser diodes are based on the InAlGaN material system. The laser diodes have utility in a number of applications including quantum computing, quantum sensing, biomedical, biotech, aerospace, marine, and defense.

[0013] BACKGROUND

[0014]

[0003] InAlGaN-based ridge waveguide laser diodes (RWG LDs) can be manufactured to support emission in multiple spatial (lateral) modes referred to as multi-mode (MM) operation by using a suitably large ridge width dimension typically larger than about 3 pm. Typical MM ridge waveguide dimensions can be, for example, 10 pm, 20 pm, 30 pm, 40 pm, 50 pm, or even larger such as 100 pm or 200 pm. The wider ridges enable larger currents to be applied without increasing the current density and this enables the laser diodes to produce high output power such as greater than 1 W, and as much as 5 W or 6 W from a single device. These laser diodes have applications where high output power is required. However, the multiple spatial modes yield a far-field (FF) pattern (the intensity pattern when the laser diode is projected onto a surface at a distance) that includes multiple side-lobes such that all radiation is not concentrated into a single central spot.

[0015]

[0004] For RWG LDs having a narrow ridge width less than about 3 pm, such as from 1.0 pm to 2.5 pm, only a single spatial (lateral) mode or a single mode (SM) is supported. The FF pattern of a SM RWG LD consists of an elongated single central spot with a roughly Gaussian distribution in intensity across the spot. These SM RWG LD have applications where high beam quality is required and high power is less important such as for use in coupling radiation into a single mode optical fiber.

[0016]

[0005] For both SM and MM RWG LDs, the spectrum of the emitted radiation contains many discrete peaks within an envelope centred around a peak wavelength. For the MM RWG LDs these peaks correspond to the supported longitudinal and lateral modes of the optical waveguide. For the SM RWG LDs the peaks correspond only to the supported longitudinal modes of the optical waveguide. As the driving current changes and also as a result of thermal fluctuations, the emission spectrum can change via mode-hopping due to the temperature dependence of the emitted wavelength. FIG. 1 shows a prior art example of the wavelength dependence of a 450 nm MM RWG LD having waveguide ridge with of 30 pm. The wavelength increases from 441 nm to 442.5 nm (1.5Attorney Docket No.: 61ZD-000510PC-407084

[0017] January 27, 2026 nm) when the drive current is increased from 0.15 A to 1.0 A. The stair-case pattern is evidence of mode-hopping. FIG. 2 shows a prior art example of the wavelength dependence of a 405 nm SM RWG LD. The wavelength continuously increases from 404.70 nm to 406.04 nm (1.34 nm) as the drive current increases from 50 mA to 200 mA, without evidence of mode hopping.

[0018]

[0006] For certain applications where wavelength stability is not critical, this temperature dependence on wavelength is not a concern. Furthermore, there are circumstances where the temperature dependence of the wavelength of RWG LDs can be used as a tuning parameter. The temperature dependence of the emission wavelength of InAlGaN RWG LDs can depend on several factors, including epi design and operating conditions. For example, Eichler (Tunable GaN-Based Laser Diode, Anna. Rep. 2001, Optoelectronics Department, University of Ulm, pages 1-5) shows a 0.01339 nm / K dependence. However, there are many applications, such as LiDAR applications and quantum applications where the requirements on both the tunability of the wavelength and the stability of the wavelength exceed what can be achieved from temperature control alone. Many of these applications also require single frequency operation that cannot be achieved from SM RWG LDs alone due to the multiple longitudinal modes. These applications require laser diode architecture that provide both wavelength selectivity and wavelength tunability.

[0019] SUMMARY

[0020]

[0007] According to the present invention, a laser diode comprises: a first section having a first electrical contact; and a second section having a second electrical contact; wherein, the first section and the second section comprise the same InAlGaN epitaxial layers; the first electrical contact overlies a first portion of the InAlGaN epitaxial layers; and the second electrical contact overlies a second portion of the InAlGaN epitaxial layers.

[0021]

[0008] According to the present invention, a laser diode comprises: InAlGaN epitaxial layers; a first master oscillator section comprising a first portion of the InAlGaN epitaxial layers, a first electrical contact overlying the first portion of the InAlGaN epitaxial layers, and a Bragg grating embedded within the uppermost cladding InAlGaN epitaxial layer; a phase adjustment section comprising a second portion of tire InAlGaN epitaxial layers and a second electrical contact overlying tire second portion of the InAlGaN epitaxial layers; and a second master oscillator section comprising a third portion of the InAlGaN epitaxial layers and a third electrical contact overlying tire third portion of tire InAlGaN epitaxial layers, wherein each of tire electrical contacts is configured to be independently addressable and is separated from air adjacent electrical contact by an airgap.

[0022]

[0009] According to tire present invention, a laser diode comprises: InAlGaN epitaxial layers; a master oscillator section comprising a first portion of tire InAlGaN epitaxial layers, a first electrical contact and overlying the first portion of the InAlGaN epitaxial layers; an embedded Bragg grating embedded within the uppermost cladding InAlGaN epitaxial layer; and a power amplifier section comprising a second portion of the InAlGaN epitaxial layers and a second electrical contact overlying the second portion of tire InAlGaN epitaxial layers, wherein each of the electrical contacts isAttorney Docket No.: 61ZD-000510PC-407084

[0023] January 27, 2026 configured to be independently addressable and is separated from an adjacent electrical contact by an airgap.

[0024]

[0010] According to the present invention a laser diode comprises: InAlGaN epitaxial layers; a first master oscillator section comprising a first portion of the InAlGaN epitaxial layers, a first electrical contact overlying (lie InAlGaN epitaxial layers, and a Bragg grating embedded in die uppermost cladding InAlGaN epitaxial layer; a phase adjustment section comprising a second portion of die InAlGaN epitaxial layers and a second electrical contact overlying the second portion of the InAlGaN epitaxial layers; a second master oscillator section comprising a third portion of the InAlGaN epitaxial layers and a third electrical contact overlying the diird portion of the InAlGaN epitaxial layers; and a semiconductor amplifier section comprising a fourth portion of the InAlGaN epitaxial layers and having a fourth electrical contact overlying the fourth portion of the InAlGaN epitaxial layers, wherein each of the electrical contacts is configured to be independently addressable and is separated from an adjacent electrical contact by an airgap.

[0025] [Oil] According to die present invention, a laser diode comprises an embedded Bragg grating.

[0026]

[0012] According to the present invention, a laser comprises a master oscillator section; and a power amplifier section; wherein the master oscillator section and the power amplifier section are configured to be independently biased.

[0027]

[0013] According to the present invention, a laser diode comprising a first section and a second section overlying common epitaxial layers, wherein the first section comprises a master oscillator and the second section is configured to change the refractive index of one or more of the underlying epitaxial layers.

[0028]

[0014] According to the present invention, a multijunction edge emitting laser diode comprises: a first laser diode according to the present invention; and a second laser diode according to the present invention, wherein the second laser diode overlies the first laser diode; and the first laser diode and tire second laser diode are configured to be independently driven.

[0029]

[0015] According to the present invention, an array of laser diodes comprises a laser diode according to tire present invention.

[0030]

[0016] According to the present invention, a semiconductor wafer comprises a laser diode according to tire present invention, a multijunction edge emitting laser diode according to the present invention, or an array of laser diodes according to the present invention.

[0031]

[0017] According to the present invention an optoelectronic system comprises a laser diode according to the present invention, a multijunction edge emitting laser diode according to the present invention, or an array of laser diodes according to the present invention.

[0032] BRIEF DESCRIPTION OF THE DRAWINGS

[0033]

[0018] The drawings described herein are for illustration purposes only. The drawings are not intended to limit the scope of the present disclosure.Attorney Docket No.: 61ZD-000510PC-407084

[0034] January 27, 2026

[0019] FIG. 1 shows a prior art example of the emission wavelength and the full-width-half-maximum (FWIIM) for a 900 pm x 30 pm MM RWG LD as a function of the driving current.

[0035]

[0020] FIG. 2 shows a prior art example of the emission wavelength and the FWHM for a 600 pm x 2.4 pm (length x width) SM RWG LD as a funchon of die driving current.

[0036]

[0021] FIGS. 3A and 3B show a cross-sectional view and a top view, respectively, of a prior art example of an RWG LD.

[0037]

[0022] FIGS.4A and 4B show a cross-sectional view and a top view, respectively, of an example of a distributed feedback (DFB) RWG laser diode provided by the present disclosure.

[0038]

[0023] FIG. 5 shows an emission spectrum of a DFB RWG LD provided by the present disclosure having a side mode suppression ratio (SMSR) of 40 dB.

[0039]

[0024] FIG. 6 shows a cross-sectional view of an example of a DFB RWG LD comprising an indium tin oxide (ITOj / SiOz embedded Bragg grating provided by the present disclosure.

[0040]

[0025] FIGS. 7A and 7B show a cross-sectional view (FIG. 7A) and a detailed view (FIG. 7B) of an example of a tunnel junction (TJ)-enabled DFB RWG laser diode comprising a Bragg grating embedded within the n-AlGaN layer above the tunnel junction provided by the present disclosure.

[0041]

[0026] FIGS. 8A-8C show an example of a DFB RWG laser diode with a Bragg grating embedded in a p-cladding layer using alternative regions of high and low Al content p-AlGaN provided by the present disclosure. FIG. 8A shows a laser diode epitaxial stack, FIG. 8B the epitaxial stack having a patterned low Al content p-AlGaN layer, and FIG. 8C an embedded Bragg grating comprising high Al content p-AlGaN within the low Al content p-AlGaN layer and with an overlying electrical contact.

[0042]

[0027] FIGS. 9A-9C show an example of a DFB RWG laser diode with a tunnel junction and Bragg grating embedded within an upper n-cladding layer where the Bragg grating comprises alternating regions of high and low Al content n-AlGaN provided by the present disclosure. FIG. 9A shows a laser diode epitaxial stack with a TJ layer and an overlying low Al content n-AlGaN cladding layer, FIG. 9B the epitaxial stack with a patterned n-AlGaN layer, and FIG. 9C a Bragg grating comprising high Al content n-AlGaN embedded within the low Al content n-AlGaN layer, and with an overlying electrical contact.

[0043]

[0028] FIGS. 10A-10D show perspective views of examples of a RWG LD (FIG. 10A), a DFB RWG LD (FIG. 10B), a master oscillator power amplifier (MOPA) LD configuration with a tapered PA section (FIG. 10C), and a master oscillator power amplifier (MOPA) LD configuration with an embedded Bragg grating in the master oscillator section and a tapered PA section (FIG. 10D).

[0044]

[0029] FIG. 11 A shows output power vs. MO current for a 450 nm SM MOPA LD for various currents through the PA section provided by the present disclosure.

[0045]

[0030] FIG. 1 IB shows the far field emission pattern for a 450 nm SM MOPA LD operating in quasi-continuous wave mode with a current of 0.3 A through the MO section and a current of 0.31 A through the PA section provided by the present disclosure.Attorney Docket No.: 61ZD-000510PC-407084

[0046] January 27, 2026

[0031] FIG. 11C shows a schematic of the SM MOPA LD used to obtain die data provided in FIGS. 11A-11B.

[0047]

[0032] FIG. 1 ID shows output power vs. current at various PA current densities for a 405 nm SM MOPA LD provided by the present disclosure.

[0048]

[0033] FIG. 1 IE shows die far field emission pattern for a 405 nm SM MOPA LD widi a current of 0.15 A through the MO section and a current of 0.4 A through the PA section provided by the present disclosure.

[0049]

[0034] FIG. 1 IF shows a schematic of the SM MOPA LD used to obtain the data provided in FIGS. 11D-11E.

[0050]

[0035] FIG. 12A shows output power vs. MO current at various PA currents for a SM DFB MOPA LD provided by the present disclosure.

[0051]

[0036] FIG. 12B shows the far field emission pattern for a SM DFB MOPA LD with an embedded Bragg grating in the MO section with a current of 0.10 A through the MO section and a current of 0.8 A through the PA section provided by the present disclosure.

[0052]

[0037] FIG. 12C shows the emission spectrum of the embedded Bragg gratin -enabled SM MOPA LD referred to in FIGS. 12A-12B.

[0053]

[0038] FIG. 13 shows a longitudinal cross-sectional view of an example of a MOPA LD with an airgap between the electrical contacts and the transparent conductive oxide layer (TOO) of the MO and PA sections as provided by the present disclosure.

[0054]

[0039] FIG. 14 shows a prior art example of a Littrow configuration for a self-injection locked LD.

[0055]

[0040] FIGS. 15A-15B show a cross-sectional view (FIG. 15A) and a top view of the sampling grating section (FIG. 15B) of a prior art example of a monolithic sampled grating distributed Bragg reflector tunable laser diode (SGDBR LD).

[0056]

[0041] FIGS. 16A-16D show an example of the process flow for selective epitaxial regrowth to remove high absorption quantum wells (QWs) from non-active sections of a multi-section RWG LD. FIG. 16A shows epitaxial layers of a LD stack, FIG. 16B the epitaxial stack with an etched trench through die active layer and overlying epitaxial layers and partially into the lower confinement layer, FIG. 16C selective epitaxial regrowth of the upper confinement layer and the upper cladding layer without regrowth of the removed active region, and FIG. 16D the epitaxial stack with the lithography mask removed.

[0057]

[0042] FIG. 17 shows a longitudinal cross-sectional view of an example of a multi-section RWG LD having two active sections (SI and S3) and a passive section (S2) where each section can be independently biased.

[0058]

[0043] FIG. 18 shows a longitudinal cross-sectional view of an example of simplified four-section SGDBR LD with a Bragg grating embedded within at least one (SI) of the active sections (SI, S3, S4) provided by the present disclosure.Attorney Docket No.: 61ZD-000510PC-407084

[0059] January 27, 2026

[0044] FIG. 19 shows an example of a prior art two-section Fabry-Perot coupled cavity LD having a long cavity section and a short cavity section, with an airgap separating the electrical contacts and tire epitaxial layers associated with the two sections.

[0060]

[0045] FIGS. 20A-20B show an example of wavelength tuning using a prior art Fabry-Perot coupled cavity two-section RWG LD realized by increasing current on tire long section only (FIG. 20 A), and by increasing the current in the short section only (FIG. 20B) using the LD shown in FIG.

[0061] 19.

[0062]

[0046] FIG. 21 shows longitudinal and cross-section views of an example of a two-section coupled RWG LD without an airgap in the epitaxial layers and with an airgap separating only the electrical contacts of the two sections as provided by the present disclosure.

[0063]

[0047] FIG. 22 is a schematic showing carrier-induced index change in an unpumped region of a two- section RWG LD without an airgap in the epitaxial layers and with an airgap between only the electrical contacts of the two sections as provided by the present disclosure.

[0064]

[0048] FIG. 23 shows a wavelength test matrix for a two-section coupled cavity RWG LD without an airgap in the epitaxial layers and with an airgap only between the electrical contacts of the two sections (FIG. 21) as provided by the present disclosure.

[0065]

[0049] FIG. 24 shows emission spectra for a two-section coupled cavity LD without an epitaxial airgap and with an airgap only between the electrical contacts of the two sections (FIG. 21) for different short cavity current and a fixed long cavity current as provided by the present disclosure.

[0066]

[0050] FIG. 25 shows peak wavelength vs. the short cavity current for various fixed long cavity currents for a two-section coupled cavity RWG LD without an epitaxial airgap and with an airgap only between the electrical contacts of the two sections (FIG. 21) as provided by the present disclosure.

[0067]

[0051] FIG. 26 shows an example of a two-section RWG LD with a carrier-induced index mirror (CIIM) separating the metal contacts of the two active LD sections where tire refractive index of the epitaxial layers underlying the two LD sections and the CIIM can be independently adjusted as provided by tire present disclosure.

[0068]

[0052] FIG. 27 shows an example of a vertically stacked multijunction edge emitting LD based on the InAlGaN material system provided by the present disclosure.

[0069]

[0053] FIG. 28 shows schematic of an example of a wafer implementation of a DFB LD array including a combiner and a semiconductor optical amplifier (SOA) configured to provide a range of wavelength selectivity and tuning provided by the present disclosure.

[0070]

[0054] FIG. 29 shows a cross-sectional scanning electron microscopy (SEM) view of a fabricated embedded Bragg grating provided by the present disclosure.

[0071]

[0055] FIG. 30 shows the SMSR (dB) vs. drive current (mA) for a DFB laser diode with embedded ITO / SiCh Bragg gratings selected for operation at different emission wavelengths provided by the present disclosure. The DFB LD has the structure shown in FIGS. 4A-4BAttorney Docket No.: 61ZD-000510PC-407084

[0072] January 27, 2026

[0056] FIG. 31 shows the voltage (V) and output power (W) vs. current (A) for a 450 nm DFB laser diode having the structure shown in FIGS. 4A-4B with Bragg grating identified as Adv-450 nm in FIG. 30.

[0073]

[0057] FIG. 32A shows a schematic perspective view of a SM MOPA LD with an airgap between the electrical contacts and die epitaxial layers of the MO and PA section provided by the present disclosure.

[0074]

[0058] FIGS. 32B-32E show far-field emission patterns of the SM MOPA laser diode shown in FIG. 32A having different tapered waveguide dimensions in the PA section provided by the present disclosure.

[0075]

[0059] FIGS. 33A-33F show perspective views of various laser diode configurations. FIG. 33A shows a prior art RWG LD. FIG. 33B shows a DFB RWG LD provided by the present disclosure. FIG. 33C shows a RWG laser diode with an embedded DFB in a portion of the RWG provided by the present disclosure. FIG. 33D shows a power amplifier LD having a tapered waveguide. FIG. 33E shows a MOPA RWG LD with an airgap between the electrical contacts and epitaxial layers of the two sections provided by the present disclosure. FIG. 33F shows a DFB MOPA RWG LD provided by the present disclosure with an embedded Bragg grating in the MO section.

[0076]

[0060] FIG. 34 shows simulated emission spectra for various RWG laser diode configurations.

[0077] DETAILED DESCRIPTION

[0078]

[0061] “Overlying” such as “a layer X overlying a layer Y” refers to a semiconductor structure in which epitaxial layer X is situated above epitaxial layer Y. Epitaxial layer X can be disposed on epitaxial layer Y such that epitaxial layer X directly contacts epitaxial layer Y. Overlying also includes structures where one or more epitaxial layers is disposed between epitaxial layer X and epitaxial layer Y such that epitaxial layer X does not directly contact epitaxial layer Y.

[0079]

[0062] “Underlying” such as “a layer X underlying a layer Y” refers to a semiconductor structure in which epitaxial layer X is situated under epitaxial layer Y. Epitaxial layer X can be disposed under epitaxial layer Y such that underlying epitaxial layer X directly contacts overlying epitaxial layer Y. Underlying also includes structures where one or more epitaxial layers is disposed between epitaxial layer X and epitaxial layer Y such that epitaxial layer X does not directly contact epitaxial layer Y.

[0080]

[0063] “Layer” includes a single semiconductor layer having a substantially lateral uniform material composition and / or function or as appropriate can include two or more sub-layers. For example, an active layer comprising a quantum well can comprise multiple alternating semiconductor layers having different compositions.

[0081]

[0064] “Lateral” refers to the dimension perpendicular to the direction of epitaxial growth and orthogonal to the epitaxial layers.

[0082]

[0065] “Longitudinal” refers to the dimension parallel to the ridge waveguide and lasing axis.

[0083]

[0066] In AlGaN refers to the semiconductor alloy InxAlyGai-x-yN where 0 <x < l, 0 <y < l, and x + y < 1. InAlGaN includes InxGai-xN, and AlyGai.yN. An In AlGaN material can be configured toAttorney Docket No.: 61ZD-000510PC-407084

[0084] January 27, 2026 emit electromagnetic radiation in a wavelength range from 380 nm to 850 nm. For example, an InAlGaN material such as InGaN can be configured to emit radiation in tire ultra violet / violet wavelength range from 365 nm to 400 nm, in the blue wavelength range of about 450 nm, in the green wavelength range of about 530 nm or in tire red wavelength range from about 620 nm to 700 nm. Similarly, reference to AlGaN can include InAlGaN.

[0085]

[0067] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard variation found in their respective testing measurements.

[0086]

[0068] Also, it should be understood that any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of “1 to 10” is intended to include all sub-ranges between (and including) the recited minimum value of 1 and the recited maximum value of 10, that is, having a minimum value equal to or greater than 1 and a maximum value of equal to or less than 10.

[0087]

[0069] Reference is now made to certain laser diodes including laser diodes provided by the present disclosure. The disclosed laser diodes are not intended to be limiting of the claims. To the contrary, the claims are intended to cover all alternatives, modifications, and equivalents.

[0088]

[0070] Laser diodes provided by the present disclosure include high power, tunable, and wavelength-stabilized MM and SM and single frequency InAlGaN LDs.

[0089]

[0071] FIG. 3 A shows a cross-sectional view and FIG. 3B shows a top view of an example of a prior art RWG LD including a bottom electrical contact 308, a substrate 301, a lower cladding layer 302, a lower confinement layer 303, an active region 304, an upper confinement layer 305, upper cladding layer 306 and a top electrical contact 307. The active region 304 can comprise a single InAlGaN quantum well (QW) or multiple InAlGaN QWs separated by InAlGaN quantum barriers (QBs) where the bandgap of the QWs is less than the bandgap of the QBs. Depending on the dimensions (length and width) of tire ridge waveguide, the RWG LD will lase in either SM or MM and will have a temperature-dependent lasing wavelength that can be used as a tuning parameter. As shown in FIG. 3B the RWG LD is characterized by a length “1” and a width “w”.

[0090]

[0072] FIG. 4A shows a cross-sectional view and FIG. 4B shows a top view of an example of SM DFB RWG LD provided by tire present disclosure. As shown in FIG. 4 A the laser diode includes a bottom electrical contact 409, an overlying substrate 401, a first cladding layer 402, a first confinement layer 403, an active region 404, a second confinement layer 405 overlying the active region 404, upper cladding layer 406, a separate Bragg grating layer 407, and a top electrical contact 408. In addition to tire epitaxial layers of a standard RWG LD (refer to FIG. 3A), this device also includes a Bragg grating layer 407 for wavelength selectivity. The Bragg grating layer 407 in this example is situated above the upper confinement layer 405 and beneath the top metal contact layer 407, and therefore the current must be able to be injected through the Bragg grating to drive theAttorney Docket No.: 61ZD-000510PC-407084

[0091] January 27, 2026 device with uniform current density. The function of the Bragg grating is to provide selective feedback of a specific wavelength as determined by the design of the Bragg grating into the active region 404. These devices are referred to as distributed feedback (DFB) LDs. The wavelength-selective feedback increases the gain at a specific wavelengtii such that only a single longitudinal mode corresponding to the selected wavelength is supported by the active region. FIG. 4B shows a top view of the Bragg grating layer 407 having length “1” and width “w” and including alternating lateral regions of low-refractive index material 407A and high-refractive index material 407B.

[0092]

[0073] FIG. 5 shows the emission spectrum of a 450 nm DFB RWG LD exhibiting a 40 dB side mode suppression ratio (SMSR). FIG. 30 shows the SMSR (dB) vs. current (mA) and FIG. 31 shows the voltage (V ) and power (W) vs. current (A) for the 450 nm DFB RWG LD used to generate the emission spectrum shown in FIG. 5 and had an ITO / SiO, grating. In FIG. 31, “Std” and “Adv” represent different DFB designs. FIG. 31 shows the voltage vs. current and power vs. current characteristics for the 450 nm DFB RWG LD implemented with the “Adv-450” DFB grating design.

[0093]

[0074] In addition to single frequency operation, the DFB RWG LD can also exhibit increased wavelength stability because the temperature dependence of the Bragg grating is not as large as the temperature dependence of the laser gain, and therefore the Bragg grating can stabilize the emitted wavelength across a wider temperature range compared to a comparable RWG LD without the embedded Bragg grating. Although the DFB configuration improves wavelength stability with respect to thermal fluemations, the design limits the ability to tune the laser frequency using temperature control.

[0094]

[0075] Another design consideration for DFB RWG LDs is the selection of materials used to form the Bragg grating. The Bragg grating utilizes periodic lateral regions of materials with differing refractive indices. Because the feedback mechanism requires an interaction between the optical mode and tire Bragg grating, the absorption coefficient of the Bragg grating at the target wavelength must be minimized to reduce or prevent additional optical loss. Furthermore, the Bragg grating must be located between the epitaxial layers and die electrical contacts to prevent large optical loss from any modal overlap with the contact metals that typically have extremely high absorption coefficients. Finally, die Bragg grating design must enable current injection dirough the Bragg grating and provide sufficient current spreading beneadi the Bragg grating to ensure uniform current injection into the underlying epitaxial layers.

[0095]

[0076] Lateral current spreading though a p-type layer of InAlGaN is poor due to the high resistivity of p-type InAlGaN. Therefore, one solution to improve lateral current spreading is to form the Bragg grating on the n-side of the laser diode and rely on the relatively high conductivity of n-type InAlGaN for the current spreading. However, this design can introduce fabrication complexities such as tiie requirement for flip-chip architecture and wafer bonding, as well as accurate substrate removal with very tight tolerance on the substrate removal process. This results because the couplingAttorney Docket No.: 61ZD-000510PC-407084

[0096] January 27, 2026 coefficient between the optical mode and the Bragg grating is governed by the confinement factor within the Bragg grating, i.e., the fraction of the optical mode that overlaps with the grating region.

[0097]

[0077] To avoid the fabrication issues, lateral current spreading can be improved by situating the Bragg grating on the p-side of the laser diode where the location can be tightly controlled during the epitaxial process. However, this configuration puls a conductivity constraint on the design to ensure that suitable current spreading occurs below the Bragg grating.

[0098]

[0078] One example of a design that can improve current spreading is illustrated in FIG. 6, which shows a DFB RWG LD with a periodic Bragg grating layer comprising alternating lateral regions of a transparent conductive oxide (TCO) such as indium-tin-oxide (ITO) and SiO2. The refractive indices are about 2.0 and 1.4 for ITO and SiO2, respectively, and provide sufficient refractive index contrast for wavelength selectivity. However, although ITO has sufficient conductivity to facilitate current spreading, it also has a high absorption coefficient in the visible wavelength range (> 1,000 cm1). The DFB LD shown in FIG. 6 is based on this design. The DFB RWG LD shown in FIG. 6 includes a substrate and epitaxial layers (not specified) 601, an overlying p-type layer 602, an ITO current spreading layer 603, and an overlying Bragg grating layer 604 comprising alternating lateral regions comprising ITO 605 and Si()2606. In some embodiments, the TCO current spreading layer is omitted. Other useful TCOs include In2O3:H (IO:H), InSnO (ITO), InZnO (a-IZO), ImO3:Zr (ZrlO); ZnO:Al (AZO), ZnSnO (a-ZTO), ZnO:B (BZO), ZnO:B (BZO), ZnO:Ga (GZO), SnO2, ZnO, CdSnO2, and CdO:In.

[0099]

[0079] To reduce the optical loss from the ITO component 605 of the Bragg grating layer 604, a suitable material can be used that is transparent at the lasing wavelength, has an electrical conductivity sufficient for current spreading, and has sufficient index contrast with respect to SiO to form the Bragg grating. A suitable candidate for this material is n-InAlGaN.

[0100]

[0080] n-InAlnGaN can be grown epitaxially during the growth of the other epitaxial layers with the insertion of a tunnel junction (TJ) to convert the conductivity of the uppermost epitaxial cladding layer from p-type to n-type. FIG. 7A shows an example of a TJ-enabled DFB RWG LD in which a Bragg grating is embedded in the uppermost cladding n-AlGaN layer 709 that is epitaxially grown above the TJ 708. FIG. 7A shows a DFB RWG LD epitaxial stack including a free-standing (FS) GaN substrate 701, an n-AlGaN layer 702, an n-type separate confinement heterostructure (SCH) layer 703, an active layer 704 comprising quantum wells (QWs), a p-SCH layer 705, an electron blocking layer (EBL) 706, a p-AlGaN layer 707, a TJ layer 708, and an overlying n-AlGaN layer incorporating an embedded Bragg grating 709. FIG. 7B shows details of the n-AlGaN layer 709 with an embedded Bragg grating having alternating lateral regions comprising the n-AlGaN layer material and a low index material 710 such as SiO2overlying tunnel junction 708.

[0101]

[0081] Referring to FIG. 7A, the TJ 708 and the n-AlGaN layer 709 can be grown using metalorganic chemical vapor deposition (MOCVD) with post-growth lateral activation for activating the buried p-type AlGaN layer 707.Attorney Docket No.: 61ZD-000510PC-407084

[0102] January 27, 2026

[0082] In another aspect provided by the present disclosure and referring to FIGS. 7A and 7B the TJ 708 and n-AlGaN 709 layer can be grown using remote plasma chemical vapor deposition (RPCVD) without requiring post-growth lateral activation by leveraging the activated-as-grown (AAG) properties of tire RPCVD growth process. See Brown et al., SPIE Proceedings, vol. 11262, High-Power Diode Laser Technology XVIII, 112620R March 2020, p. 26, 2020, doi:

[0103] 10.1117 / 12.2548261; and Barik et al., SPIE Proceedings, Vol. 10940, Light-Emitting Devices, Materials, and Applications, 1094018, Mar. 2019, p. 44. doi: 10.1117 / 12.2513261. The n-AlGaN region has a refractive index of about 2.45 providing an even larger index contrast with respect to SiOz than ITO, and the absorption coefficient of n-AlGaN can be engineered to be significantly lower than that of ITO such as about 10 cm1compared to greater than 1,000 cm1for ITO.

[0104]

[0083] According to another aspect provided by the present disclosure, a Bragg grating can be formed entirely by epitaxy.

[0105]

[0084] For example, first, the epitaxial layers of the laser diode up to the upper cladding layer can be grown with the upper cladding layer comprising p-type AlGaN having an Al content from 0% to 20%, such as from 0% to 10%, or from 0% to 5%. Then, the p- AlGaN can be etched to form trenches, and finally the trenches can be filled by regrowth of high Al content p- AlGaN. FIGS. 8 A-8C show an example of this DFB RWG LD structure and the process steps. FIGS. 8A-8C show an LD epitaxial stack having an n- AlGaN layer 801, epitaxial layers 802, and an upper p- AlGaN layer 803. FIG. 8B shows p- AlGaN layer etched to provide a patterned p- AlGaN layer 803A, and FIG. 8C shows a high- Al content p-AlGaN material 803B grown between the patterned p-AlGaN regions 803A to provide a Bragg grating embedded within p- AlGaN layer 803 with an electrical contact 804 overlying the embedded Bragg grating. As shown in FIG. 8C an embedded Bragg grating can comprise alternating layers of high- and low-Al content p-AlGaN embedded.

[0106]

[0085] A cross-sectional scanning electron microscopy (SEM) view of a fabricated embedded Bragg grating is shown in FIG. 29. As shown in FIG. 29, the fabricated DFB RWG LD includes epitaxial layers 2901 with a p- AlGaN top layer, ITO layer 2902, embedded Bragg grating including alternate regions of ITO 2903 and SiOz 2904 and overlying electrical contact 2905.

[0107]

[0086] Growth of low resistance, high- Al content p- AlGaN is challenging because the activation energy of tire Mg acceptor increases with increasing Al content. Generally, when using MOCVD high- Al content p- AlGaN must be grown at high temperatures to maximize conductivity, however, high temperature can damage the thermally sensitive InGaN QWs in the epitaxial stack. This is of particular concern when growing longer wavelength LDs (> 450 nm) where the higher indium content InGaN is even more sensitive to thermal damage. To circumvent this issue the high- Al content p-AlGaN can be grown using RPCVD. RPCVD does not require such high growth temperatures because the density of active nitrogen is controlled by the introduction of Nz plasma, rather titan by the thermal dissociation of NHz as is the case in MOCVD.Attorney Docket No.: 61ZD-000510PC-407084

[0108] January 27, 2026

[0087] In another aspect provided by the present disclosure, an epitaxially grown embedded Bragg grating can be formed using alternating lateral regions of n-AlGaN rather than p-AlGaN by utilizing a TJ inserted beneath the low- Al content AlGaN layer during the initial epitaxial steps. The n-AlGaN layers can provide significantly more current spreading than p-AlGaN layers, thereby decreasing the series resistance, and enabling operation at lower voltage, as long as die TJ can be designed to have sufficiently low optical loss and resistance. This approach is illustrated in FIGS. 9A-9C.

[0109]

[0088] FIGS. 9A-9C show a LD stack having a substrate 901, overlying epitaxial layers 902 including one or more p- AlGaN layers, a tunnel junction layer 903, and an overlying low- Al content n- AlGaN layer 904. As shown in FIG. 9B, low-Al content n- AlGaN layer can be etched to provide a patterned low-Al content n-AlGaN layer 904A. FIG. 9C shows high Al-content n-AlGaN 904B grown in the patterned regions to provide an embedded n-AlGaN Bragg grating and with an overlying electrical contact layer 905.

[0110]

[0089] Referring to FIG. 9, the TJ 903 and low- and high- Al content n-AlGaN materials 904A / 904B can be grown by RPCVD to retain the activation of the buried p-type AlGaN layer 902.

[0111]

[0090] For the LD structures provided by the present disclosure an important consideration is the output power. Both the SM RWG LDs and SM DFB RWG LDs can be limited to low to moderate output powers compared to MM RWG LDs for at least two reasons. First, the narrow width of the ridge waveguide, for example a width less than 10 pm can increase the current density and limit how much drive current can be applied to the LDs without device failure. Second, even for modest current densities the SM RWG LDs can begin to support higher order optical modes and display non-SM behavior.

[0112]

[0091] To minimize or eliminate die propagation of higher order modes the SM RWG LD structures can be combined with a semiconductor optical amplifier (SOA) in a master oscillator (MO) power amplifier (PA) configuration (MOPA). FIG. 10A shows a perspective view of a standard SM RWG LD including substrate 1001, lower cladding layer 1002, epitaxial layers including active region 1003, and upper cladding layer 1004. FIG. 10B shows a SM DFB RWG LD including substrate 1001, lower cladding layer 1002, epitaxial layers including active region 1003, and upper cladding layer with an embedded DFB 1005 extending the length of the SM RWG LD. FIG. 10C shows a MOPA with a tapered PA section 1010. The concept behind the MOPA is that the MO section 1009 can be engineered to produce the desired laser optical characteristics which are then fed into the PA section 1010 for amplification without loss of the key optical characteristics. FIG. 10C shows a MOPA configuration in which the MO section 1009 as a standard SM RWG-LD and includes substrate 1001, lower cladding 1002, epitaxial layers including active region 1003, and upper cladding layer 1004 without an embedded Bragg grating. The electrical contacts or both the electrical contacts and the epitaxial layers of MO section and the PA sections are separated by airgap 1007 through the epitaxial layers and active region. The MO section 1009 produces single spatial mode emission that isAttorney Docket No.: 61ZD-000510PC-407084

[0113] January 27, 2026 amplified by the tapered PA section 1010 while maintaining the SM behavior. The tapered PA section 1010 includes the same layers and materials as in the MO section, however the epitaxial layers and n-type layer is tapered to have a width greater than that of the n-type layer of the MO section.

[0114]

[0092] FIG. 10D shows a SM DFB MOPA RWG LD with a structure similar to that of FIG. 10C except that the RWG of the MO section incorporates a Bragg grating 1008. The LD structure shown in FIG. 10D includes substrate 1001, lower cladding layer 1002, epitaxial layers including active region 1003, upper cladding layer 1008 incorporating and embedded Bragg grating in the MO section, and upper cladding layer 1006 without an embedded Bragg grating in the PA section.

[0115]

[0093] FIG. 11 A shows the measured output power of a 450 nm SM MOPA LD as a function of the MO drive current for different PA currents. FIG. 11B shows the measured far-field (FF) laser beam profile measured with a 0.3 A drive current through the MO section and a drive current of 3.1 A through the PA section. The curves confirm that the PA section is amplifying the output power, and the FF pattern confirms that the single mode behavior of the MO laser is maintained even up to an output power of greater than 1.25 W. The SM MOPA LD referred to in FIGS. 11 A- 1 IB include an airgap between the electrical contacts and epitaxial layers including the active layer of the MO and PA sections. FIG. 11C shows a schematic of the SM MOPA LD referred to in FIGS. 11A-11B and shows the single-mode master oscillator section, the airgap, and the power amplifier section with the tapered RWG LD. The MO and PA sections are interconnected to independent drivers.

[0116]

[0094] FIG. 32 A shows a perspective view of a SM MOPA LD and FIGS. 32B-32E show far field emission patterns for the 450 nm emitting SM MOPA LDs of FIG. 32A with width “w” of the tapered PA waveguide output from 2.4 pm to 50 pm. The SM MOPA LD used to generate the FF emission patterns had a structure similar to that of the SM MOPA LD shown in FIG. 11C.

[0117]

[0095] FIGS. 1 ID- 1 IF refer to a SM MOPA LD having a similar structure to that referred to in FIGS. 11 A- 11C except that the LD is operating at a wavelength of 405 nm. FIG. 1 ID shows the power vs. current at various PA current densities, FIG. 1 IE the measured FF laser beam profile measured at MO current of 0.15 A and a PA current of 0.4 A, and FIG. 1 IF shows a schematic of the SM MOPA LD referred to in FIGS. 1 ID- 1 IE. There are two results to note in the current vs. power curves. First, the device is lasing even with 0 A on the MO, and second the device is lasing with 0 A on the PA. Not only does this indicate that the reflectivity of the AR coating on the wide facet of the MOPA may have been too high.

[0118]

[0096] FIGS. 12A-12C refer to a SM DFB MOPA RWG LD having an airgap between the electrical contacts and the epitaxial layers including the active layer of the MO and PA sections. FIG.

[0119] 12A shows the output power as a function of the MO current for different PA currents. FIG. 12B shows the far field (FF) emission pattern for the SM DFB MOPA RWG LD at a PA current of 0.8 A, a MO current of 0.10 A, and an output power (QCW) of 0.4 W. FIG. 12C shows the output spectrum at a center wavelength of about 456.3 nm. The SM DFB MOPA RWG LD had a structure similar toAttorney Docket No.: 61ZD-000510PC-407084

[0120] January 27, 2026 that of the MOPA RWG LDs referred to in FIGS. 11A-11F, but the MO section included an embedded Bragg grating in the uppermost epitaxial cladding layer.

[0121]

[0097] Multi-section LDs with airgaps separating epitaxial layers including the active layer of tire have been disclosed, for example, by Guziy et al., AIP Adv., 2024; and Derickson et al., Proceedings SPIE Vol. 6847, Coherence Domain Optical Methods and Optical Coherence Tomography in Biomedicine XI 1. 68472P, 2008. Although airgaps provide distinct mirrors for separating each section in any multi-section LD, to achieve low power loss the airgaps must have high-quality, smooth etched facets, and the facets between the sections must be suitably passivated. This is difficult to achieve using standard thin film facet coating technologies, which are highly directional making it difficult to control the coating thickness in the sidewalls of high aspect ratio trenches. Acceptable MOPA characteristics without airgap separation can be achieved by creating subtle index changes induced by the different current densities between the two MOPA sections and between both pumped sections and the unpumped region that separate the pumped sections. The subtle refractive index changes caused by the differing driving currents can be leveraged in many different multi-section LD architectures as provided by the present disclosure.

[0122]

[0098] MOPA LDs without an airgap in the epitaxial layers can be fabricated without the need for deep etching, i.e., etching through the epitaxial layers, and also without the need to AR coat the exposed facets.

[0123]

[0099] FIG. 13 shows a MOPA LD having a TCO layer 1302 overlying the epitaxial layers 1301 and an electrical contact layer 1303 overlying the TCO layer 1302. An airgap 1306 separates only the conductive oxide layer 1302 and the electrical contact layer 1303 of the MO section 1304 and PA section 1305. There is not an airgap in the epitaxial layers 1307.

[0124]

[0100] As an alternative configuration to the MOPA LD shown in FIG. 12C having an airgap only between the contacts of the MO and PA sections, the MOPA LD can include an etched airgap that extends partially into the epitaxial layers such as, for example, through only the uppermost epitaxial cladding layer or partially through the uppermost epitaxial cladding layer.

[0125]

[0101] SM and MM RWG LDs, DFB LDs, and MOPA LDs employing either a SM or a DFB section as the MO provided by tire present disclosure facilitate tire ability to control the mode of operation (MM, SM, single frequency), control of tire far-field emission pattern, improve wavelength stability (in the case of the DFB devices), and amplify the power output without loss of optical quality. However, these implementations alone do not necessarily provide a method for tuning the lasing wavelength beyond what can be achieved via thermal tuning (noting the reduced ability thermally tune when combined with wavelength selective feedback). A common method for wavelength tuning, known as self-injection locking, involves taking a fraction of the output emission from the MO or MOPA laser, filtering the emission using a suitable wavelength selective method such as a Bragg grating, and feeding the selected emission back into the PA laser cavity. This locks the lasing wavelength of the PA laser to the injected wavelength in the same way that the BraggAttorney Docket No.: 61ZD-000510PC-407084

[0126] January 27, 2026 grating in a DFB LD stabilizes the emission wavelength by increasing the gain at the feedback wavelength. A typical configuration for this is known as the Littrow configuration and is shown in FIG. 14, where the angle of the grating is adjusted to select tire locking wavelength. Using a similar configuration, a tunable range of about 7 nm for a green LD with a 28 dB SMSR has been demonstrated, for example, by Shamim et al., Optics Letters, Vol. 43, Issue 20, pp. 4931-4934, 2018. FIG. 14 includes a laser on a Peltier submount, a collimating lens, a diffraction grating, a focusing lens and an optical fiber.

[0127]

[0102] For practical applications such as, for example, LiDAR and certain quantum sensing applications, it is desirable to achieve similar injection locking and tuning capabilities within a single chip for reasons including portability, size and weight, cost of manufacture, resistance to vibrations, and robustness in harsh environments. For operation at non-visible wavelengths, a common configuration for such a device is a sampled grating distributed Bragg reflector (SGDBR) monolithic tunable laser diode. A SGDBR LD can consist of up to five sections on a single chip as illustrated in FIG. 15A, and discussed in Dickerson et al., Ibid. FIG. 15A shows a cross-sectional view and FIG.

[0128] 15B shows a top view of the sampling grating section of an example of a prior art sampled grating distributed Bragg reflector SGDBR LD monolithic tunable laser. The SGDBR LD shown in FIGS.

[0129] 15A and 15B includes a back mirror 1501 , a gain section 1502, a phase section 1503, a front mirror 1504, and a semiconductor optical amplifier (SOA) 1505. FIG. 15B shows a configuration of the DFB mirrors including subgratings and sampling period.

[0130]

[0103] Although SGDBR lasers have been demonstrated in other material systems such as at infrared (IR) wavelengths, there are no reports of SGDBRs operating at visible wavelengths. Aspects provided by the present disclosure provide visible wavelength SGDBRs fabricated using tire InAlGaN material system.

[0131]

[0104] As one approach to realize a visible wavelength SGDBR LD the gap regions between adjacent sections can be fabricated by etching and regrowth of the absorbing regions. Several key design features of a SGDBR structure are illustrated in FIGS. 15A and 15B. One challenge of the implementation shown in FIGS. 15A-15B is the requirement that there be a lateral variation in the bandgap between the active regions such as between tire gain section 1502 and the SOA 1505, and between the non-active regions such as the mirrors 1501 / 1504 and the phase section 1503 such that the passive sections do not absorb at tire lasing wavelength. Implementing these in the InAlGaN system can be achieved, for example, using an etch and selective regrowth process as illustrated in FIGS. 16A-16D.

[0132]

[0105] The semiconductor structures shown in FIGS. 16A-16D include substrate and lower epitaxial layers 1601, lower confinement layer 1602, active layer 1603, upper confinement layer 1604, cladding layer 1605, etch mask 1606, etch trench 1607, selective regrowth of upper confinement layer 1608A, selective regrowth of cladding layer 1608B, and merged confinement layers 1609. As shown in FIG. 16A, die epitaxial layers up to and including the upper cladding layer 1605 are first grown.Attorney Docket No.: 61ZD-000510PC-407084

[0133] January 27, 2026 Then the passive region is etched through to at least the bottom of the active region 1603 using standard lithography techniques and a SiO: hard mask 1606. The passive waveguide layers 1608A / 1608B are then regrown selectively using MOCVD where the growth will only occur in the etched region not covered by tire SiO: mask 1606. Finally, as shown in FIG. 16D tire SiOi mask is removed. An epitaxial material region 1609 isolates tire active layer 1603 of lire adjacent sections of the laser diode.

[0134]

[0106] FIG. 17 illustrates an alternative method for bridging adjacent LD sections that does not require etching or regrowth. In this example, there are two active sections SI and S3 separated by a passive section S2. All three sections contain identical epitaxial layers and therefore tire passive section S2 would, if unbiased, represent a lossy waveguide region as it would have the same bandgap as that of the active sections and therefore would absorb the laser light. To reduce absorption (loss) in the passive section S2, a bias (V2) can be applied such that the current flowing through passive section S2 is just below the lasing threshold. At this current, the pumped QWs will be close to transparency and therefore will not absorb the laser radiation generated in the adjacent active sections SI and S3. For example, SI and S3 can be biased at different voltages (VI and V3) such as in a MOPA configuration. The semiconductor structure shown in FIG. 17 also includes substrate 1701, lower epitaxial layers including lower confinement layer 1702, active region 1703, upper confinement layer 1704, and upper cladding layer 1705. Sections SI, S2, and S3 include independent electrical contacts 1706, 1707, and 1708, respectively, with adjacent electrical contacts separated by airgaps 1709 and 1710.

[0135]

[0107] The S2 section can be at an end of the device, i.e, to the right of sections S4 in FIG. 18, such that the entire substrate 1801 can be combined with another optoelectronic element or optical fiber. This extra length of waveguide made in InAlGaN material can be pumped below threshold to act as a low loss waveguide and used to optically connect the end of the laser diode to another device. For example, the optical waveguides shown in Figure 28 (to the right of the individual tunable laser sections S1 / S2 / S3 / S4 can be long InAlGaN waveguides and can be pumped below threshold. In this configures the S2 section does not function as wavelength tuning element.

[0136]

[0108] Another consideration for realizing the SGDBR structure in the InAlGaN material system is the Bragg mirrors. In the example shown in FIGS. 15A-15B, the Bragg mirrors are formed in sections that are separate from die two active regions and dierefore require lower bandgap waveguides to avoid absorption loss. As shown in FIGS. 4A-4B, diis can be achieved in die InAlGaN system using a DFB architecture where die Bragg grating is embedded widiin a layer situated between the electrical contact and die upper cladding layer. This configuration reduces the total number of required sections from a minimum of five for the SGDBR shown in FIGS. 15A-15B to a minimum of four.

[0137]

[0109] FIG. 18 shows an example of this structure. As shown in FIG. 18, section SI includes a DFB-enabled active region that provides the single frequency MO laser source. Section S2 is a phaseAttorney Docket No.: 61ZD-000510PC-407084

[0138] January 27, 2026 section that incorporates a structure for minimizing optical loss such as use of a suitable etch and regrowth step to remove the active region. Section S3 represents a second active region, which can be a standard SM laser section. Section S3 can also be a second DFB-enabled section with a different grating design to enable Vernier tuning via adjustment of the relative bias applied to sections SI and S3. The Bragg gratings in sections SI and S3 can be sampled gratings designed to alter the reflectivity spectrum and to enable wavelength tuning via adjustment of the relative bias applied to sections SI and S3. SOA section S4 has the same active layer as sections SI and S3 to achieve gain similar to the MOPA LD shown in FIGS. 10C-10D and FIG. 11C. In FIG. 18, element 1801 represents the substrate and various epitaxial layers, 1809 represents an embedded Bragg grating, elements 1802 / 1803 / 1804 / 1805 represent the electrical contacts for each of respective sections S1 / S2 / S3 / S4., and the electrical contacts of adjacent sections are isolated by airgaps 1806 / 1807 / 1808.

[0139]

[0110] Other viable designs can eliminate the phase section S2 and / or SOA section S4.

[0140]

[0111] A two-section Fabry-Perot coupled laser can provide tuning capabilities using the Vernier effect. A prior art example of such a configuration is shown in FIG. 19. See Guziy et al., AIP Advances, 2(3) 032130, 2012. FIG. 19 shows a configuration in which two sections of the LD have different lengths and are coupled via a sub-wavelength airgap. The two sections can be driven independently and therefore can be tailored to have different current densities during operation. It is known that the refractive index of semiconductors can be influenced by carrier injection, and a change in the refractive index will affect the lasing wavelength. However, the impact on the wavelength from the carrier-induced index change alone is very small. The LD shown in FIG. 19 includes substrate 1901, lower cladding layer 1902, active layer 1903 emitting at wavelength X, long-cavity upper cladding layer 1904, and short-cavity upper cladding layer 1905. The long-cavity section and the short-cavity section can be separated by airgap 1906 and can be independently driven by applying respective current ILor Is.

[0141]

[0112] For a two-section coupled cavity laser as shown in FIG. 19, the lasing wavelength is also influenced by the Vernier effect, where the longitudinal mode jumps from one mode to another due to resonances between the cavities which can be controlled by adjusting the relative current densities between the sections. As shown in FIG. 20A, increasing the current in the long cavity section causes a blueshift in the wavelength, and as shown in FIG. 20B increasing the current in the short cavity section causes a redshift in the wavelength. See Guziy et al., AIP Advances, 2(3) 032130, 2012.

[0142]

[0113] Vernier tuning can also be achieved without an airgap separating the epitaxial layers. For example, the active regions can be isolated using an electrical gap of about 10 pm such that the electrical contacts to the independent active regions are isolated.

[0143]

[0114] Without an airgap separating the epitaxial waveguide layer, carrier-injected-induced index changes beneath the unpumped region (the gap in the contact) are controlled to induce reflectivity between the sections. These refractive index changes will be very small but have been shown to be sufficient to demonstrate the Vernier effect. The use of an electrical gap or material gapAttorney Docket No.: 61ZD-000510PC-407084

[0144] January 27, 2026 as opposed to an airgap can greatly simplify the LD fabrication process and can also increase the lifetime and reliability of the devices by eliminating the need to incorporate passivated facets. Two-section coupled cavity LDs can incorporate a sub-wavelength airgap separating tire waveguide sections. The airgap can be formed using standard semiconductor etching techniques and although there can be challenges in ensuring the etched facets are smooth, the major limitation of these designs is in the difficulty passivating the facets facing the airgap.

[0145]

[0115] Following from the successful demonstration of a MOPA RWG LD without an airgap in the epitaxial layers (see e.g., FIG. 13), a simple two-section SM RWG LD without an airgap in the epitaxial waveguide layer was fabricated. The device structure is shown in FIG. 21 and includes a substrate and lower epitaxial layers 2101, lower confinement layer 2102, an active layer comprising quantum wells 2103, an upper confinement layer 2104, an upper cladding layer 2105, and electrical contact layers 2106 and 2107, separated by airgap 2108. Without an airgap separating the epitaxial (waveguide) layers, carrier-injected-induced index changes beneath die unpumped region (the gap between the electrical contact layers) is relied on to induce reflectivity between the sections.

[0146]

[0116] This is illustrated schematically in FIG. 22. Although the refractive index changes are very small, the changes have shown to be sufficient to produce the Vernier effect. The LD shown in FIG. 22 includes lower epitaxial layers 2202, active layer 2203, upper confinement layer 2204, upper cladding layer 2205, electrical contact layers 2206 and 2207 separated by an airgap 2209, a local refractive index change 2208 in the unpumped region, the upper confinement layer 2204, and upper cladding layer 2205 and the current gradients caused by different injection currents to the two sections. Region 2208 represents a refractive index change as a result of carrier-induced index changes between the unpumped and the two pumped sections.

[0147]

[0117] FIG. 23 shows a wavelength test matrix for a two-section cavity RWG LD without an airgap between the epitaxial layers as shown in FIGS. 21-22 when the short cavity current and long cavity current are independently adjusted. Within the test conditions a wavelength tuning range of 2.18 nm, e.g. from 448.95 nm to 451.13 nm, was demonstrated.

[0148]

[0118] FIG. 24 shows tire spectral evolution of a two-section cavity RWG LD as shown in FIGS.

[0149] 21-22 as a function of short cavity current (SCC) for a fixed long cavity current (LCC) of 200 mA. As shown in FIG. 24, the wa velength peak emission wavelength redshifted as tire SCC increased from 40 mA to 100 mA and exhibited a strong blueshift as the SCC increased from 100 mA to 200 mA, followed by a redshift at an SCC from 200 mA to 300 mA.

[0150]

[0119] FIG. 25 shows the peak emission wavelength as a function of the SCC for various fixed LCCs a two-section cavity RWG LD as shown in FIGS. 21-22. There are two distinct regimes highlighted by the dashed lines with dashed arrows. In regime 1 (dashed lines with downward arrows) a sharp blueshift (decrease in wavelength) for an increase in SCC was observed. In regime 2 (dashed lines with upward arrows) a slow redshift (increase in wavelength) for an increase in SCC was observed. This result is in contrast to the wavelength-current relationship of a standard singleAttorney Docket No.: 61ZD-000510PC-407084

[0151] January 27, 2026 section SM RWG LD (FIG. 2) which exhibits a linear redshift in wavelength with an increase in current due to heating. These results demonstrate that a multiple-section coupled cavity InAlGaN wavelength tunable laser can be formed using only current injection gaps, without airgaps in tire epitaxial (waveguide) layers. This method can greatly simplify the RWG LD fabrication process and can also increase the lifetime and reliability of tire devices resulting from tire absence of passivated facets.

[0152]

[0120] To further leverage the use of carrier-induced refractive index control to form indexcontrast embedded mirrors within tire waveguide sections of a RWG LD an ultra-short carrier-induced index mirror (CIIM) can be placed within a gap between the electrical contacts of adjacent active sections. This configuration is illustrated in FIG. 26 which shows a two-section S1 / S2 coupled cavity LD separated by a CIIM 2603. The index nl and n2 correspond to the refractive indexes of the waveguides of section S 1 and section S2, respectively. 1'he refractive index n3 separates the two sections and can be controlled by adjusting the bias applied to the CIIM 2603. Changing the current through the CIIM can induce a local refractive index change n3 and can be used to tune the degree of optical isolation between the two sections. FIG. 26 shows epitaxial layer 2601, electrical contacts 2601 / 2604 of respective MO sections S1 / S2, and airgaps 2605.

[0153]

[0121] FIGS. 33A-33F show perspective views of various laser diode configurations. FIG. 33 A shows a prior art RWG LD. FIG. 33B shows a DFB RWG LD provided by the present disclosure. FIG. 33C shows a RWG laser diode with an embedded DFB in a portion of the RWG provided by the present disclosure. FIG. 33D shows a power amplifier LD having a tapered waveguide. FIG. 33E shows a MOPA RWG LD with an airgap between the electrical contacts and epitaxial layers of the two sections or an airgap only between the electrical contacts of the two sections provided by the present disclosure. FIG. 33F shows a DFB MOPA RWG LD provided by the present disclosure with an embedded Bragg grating in the MO section and an airgap between tire electrical contacts and epitaxial layers of the two sections or an airgap only between the electrical contacts of tire two sections provided by the present disclosure.

[0154]

[0122] FIG. 34 shows simulated emission spectra for various RWG laser diode configurations including an example of a multimode emission spectrum for a RWG LD, an emission spectrum for a MOPA RWG LD provided by the present disclosure, an emission spectrum for a SM RWG LD, and an emission spectrum for a SM DFB RWG LD provided by the present disclosure.

[0155]

[0123] A RWG laser diode provided by tire present disclosure can be configured for single mode or multimode operation. A SM RWG laser diode provided by the present disclosure can be configured to emit radiation with a FWHM, for example, of less than 5 nm, less than 1 nm, less titan 100 pm, or less than 1 pm. For a DFB RWG LD the FWHM can be, for example, less than 10 pm, less than 1 pm, less than 0.1 pm, less than 0.01 pm, or less than 0.001 pm. A laser diode provided by the present disclosure can be configured to provide an output power, for example, greater than 0.01 W, greater than 0.05 W, greater titan 0.1 W, greater than 0.5 W, greater than 1 W, or greater than 5 W.Attorney Docket No.: 61ZD-000510PC-407084

[0156] January 27, 2026 A laser diode provided by the present disclosure can be configured to emit multimode radiation or single mode radiation within a wavelength range, for example, from 200 nm to 550 nm, from 250 nm to 550 nm, from 280 nm to 550 nm, from 350 nm to 550 nm, from 375 nm to 550 nm, or from 400 nm to 500 nm. A laser diode provided by the presentation can comprise an active region based on the IiiyAlxGai-x-yN where 0 < x < l, 0 <y < l, and x and y are both not 0. For example, an active region can comprise InxGai.xN where 0.01 < x < 0.40.

[0157]

[0124] A laser diode provided by the present disclosure can comprise one active section, two active sections, three active sections, or more than three active sections. An active section is also referred to as a master oscillator (MO) section.

[0158]

[0125] An active section can comprise a DFB active section. A laser diode can comprise one DFB active section, two DFB active sections, three DFB active sections, or more than three active sections.

[0159]

[0126] Each of the one or more active sections can be independently biased.

[0160]

[0127] A DFB-enabled active section can comprise an embedded Bragg grating. An embedded Bragg grating can comprise alternating lateral regions having a different refractive index. An embedded Bragg grating can comprise alternating lateral regions, for example, alternating regions of high and low Al content n-InAlGaN, high and low Al content p-InAlGaN, or n-AlGaN and SiCh,

[0128] A laser diode provided by the present disclosure can comprise a phase control section such as one phase control section, two phase control sections, three phase control sections, or more than three phase control sections. A phase control section can be disposed between two active sections.

[0161]

[0129] A laser diode provided by the present disclosure can comprise a carrier induced index mirror (CIIM), two CIIMs, three CIIMs, or more than three CIIMs.

[0162]

[0130] A laser diode provided by the present disclosure can comprise a semiconductor optical amplifier (SOA) section. A SOA can comprise, for example, a tapered waveguide. A SOA can comprise a DFB grating. A SOA can require low anti-reflective coating to prevent laser threshold and feedback into the oscillator cavity. A SOA facet can be angled to reduce the reflectivity of the facet. The SOA ridge or waveguide section can be bent to reduce the reflectivity of the facet.

[0163]

[0131] For example, a laser diode provided by the present disclosure can comprise a first active section, a second active section, and a SOA.

[0164]

[0132] For example, a laser diode provided by the present disclosure can comprise a DFB active section, an active section, and a SOA.

[0165]

[0133] For example, a laser diode provided by the present disclosure can comprise a first DFB active section, a second DFB active section, and a SOA.

[0166]

[0134] For example, a laser diode provided by the present disclosure can comprise a first active section, a phase control section, a second active section, and a SOA.Attorney Docket No.: 61ZD-000510PC-407084

[0167] January 27, 2026

[0135] For example, a laser diode provided by the present disclosure can comprise a DFB active section, a phase control section, an active section, and a SOA.

[0168]

[0136] For example, a laser diode provided by the present disclosure can comprise a first DFB active section, a phase control section, a second DFB active section, and a SOA.

[0169]

[0137] In a laser diode provided by the present disclosure, each of the sections such as an active section, a DFB active section, a phase control section, and a SOA section can be separated, for example, by an airgap, and electrical isolation gap, or a gap in the active layer and other epitaxial layers. In airgap isolation, the airgap can extend through the epitaxial stack and through the active layer. The side walls or facets of the airgap can include an anti-reflective coating. In electrical isolation, the airgap only electrically isolates the transparent conductive oxide layer and / or the metal contact layer that overlie the epitaxial layers. The electrical isolation gap does not extend into the epitaxial layers or does not extend to the active layer. The electrical isolation gap can extend into one or more epitaxial layers but not into the active layer. The electrical isolation gap can comprise an airgap or can comprise an electrical insulator. Bridging between adjacent sections can also be realized by removing the active layer between adjacent sections and regrowing a semiconductor material bridging the active layer of the adjacent sections with a semiconductor material transparent to the lasing wavelength of the laser diode. Alternatively, electrical isolation between adjacent sections can be realized using ion implantation.

[0170]

[0138] In a laser diode provided by the present disclosure, each of the sections such as an active section, a DFB active section, a phase control section, and a SOA section, can be integrated at the epitaxial layer wafer level. For example, in a laser diode provided by the present disclosure, the sections can be epitaxially grown on a common substrate and can comprise the same continuous epitaxial layers. In certain embodiments, only tire transparent conductive oxide layer and the metal contact layer can be discontinuous such that adjacent sections are electrically isolated.

[0171] A high power multijunction edge emitting laser can be fabricated using tunnel junctions situated between vertically stacked lasers. The tunnel junctions can be fabricated using RPCVD to retain activation of underlying p-type materials. Various RPCVD / MOCVD re-growths can be introduced to achieve the best epitaxial quality and take advantage of the low growth temperature of RPCVD for the n- and p-type n-InAlGaN materials. The active regions of tire laser diodes can comprise varying levels of indium to control the wavelength of each of the stacked lasers.

[0172]

[0139] FIG. 27 shows an example of a multijunction edge emitting laser provided by the present disclosure. As shown in FIG. 27, the InAlGaN-based laser diode stack comprises three laser diodes (2701 / 2702 / 2703) in which the epitaxial layers associated with each laser diode are separated by an++ / p++ tunnel junction. The LD stack shown in FIG. 27 comprises first LD 2701 including n-AlGaN layer 2701A, active region including InGaN quantum wells and laser output 2701B, and p-InGaN layer 2701C; first n+7p++tunnel junction 2704; second LD 2702 including n-AlGaN layer 2702A, active region including InGaN quantum wells and laser output 2702B, and p-InGaN layer 2701C;Attorney Docket No.: 61ZD-000510PC-407084

[0173] January 27, 2026 second n++ / p++tunnel junction 2705; and third LD 2703 including n-AlGaN layer 2703A, active region including InGaN quantum wells and laser output 2703B, and p-InGaN layer 2703C. The LD stack overlies n-GaN substrate 2706 and includes n-contact 2707 and p-contact 2708. One or more of the laser diodes can comprise a layer such as an uppermost epitaxial cladding layer comprising an embedded Bragg grating.

[0174]

[0140] Laser diodes provided by the present disclosure can be combined to provide laser diode arrays. One example of a laser diode array is provided in FIG. 28 which shows a schematic view of an array of multiple three-section tunable DFB LDs emitting at wavelengths I to Xn, coupled through respective optical waveguides to an optical combiner, which is optically coupled to a SOA. The optical combiner can comprise any conventional optical combining architecture including low loss materials such AWGs, SiN, or mirrors such as two-dimensional or three-dimensional mirrors, or other low loss couplings.

[0175]

[0141] Laser diode arrays can be fabricated at the wafer level to provide integrated and compact devices.

[0176]

[0142] A laser diode provided by the present disclosure can comprise an embedded Bragg grating. The laser diode can be configured to operate as a single mode laser or as a multimode laser. The laser diode can be a ridge waveguide laser diode.

[0177]

[0143] The embedded Bragg grating can be a continuous grating, a sampled grating, or a combination thereof. The embedded Bragg grating can be embedded in the uppermost epitaxial cladding layer of an epitaxial stack. The uppermost epitaxial cladding layer can be, for example, an n-InAlGaN layer or a p-InAlGaN layer. The uppermost epitaxial cladding layer can be disposed on the p-side of the epitaxial stack. The embedded Bragg grating can comprise alternating lateral regions of a low refractive index material and a high refractive index material.

[0178]

[0144] The alternating lateral regions can be disposed orthogonal to the longitudinal direction of the laser cavity. The alternating lateral regions can comprise, for example, alternating lateral regions of a transparent conductive oxide such as indium tin oxide and SiCh; alternating lateral regions of low Al-content p-InAlGaN and a high Al -content p-InAlGaN; alternating regions comprise alternating lateral regions of n-InAlGaN and SiO ; or alternating lateral regions of low Al-content n-InAlGaN and a high Al-content n-InAlGaN.

[0179]

[0145] The laser diode can comprise epitaxial layer. The epitaxial layers can comprise InAlGaN. The epitaxial layers can comprise an n-InAlGaN layer; an active layer overlying the n-InAlGaN layer; and a p-InAlGaN layer overlying the active layer. The epitaxial layers can comprise a first n-InAlGaN layer; an active layer overlying the n-InAlGaN layer; an p-InAlGaN layer overlying the active layer; a tunnel junction overlying the p-InAlGaN layer; and a second n- InAlGaN layer overlying the tunnel junction.

[0180]

[0146] The active layer can comprise InAlGaN or InGaN. The active layer can comprise multiple quantum wells.Attorney Docket No.: 61ZD-000510PC-407084

[0181] January 27, 2026

[0147] The laser diode can comprise a transparent conductive oxide layer such as an indium tin oxide overlying the epitaxial layers and underlying an electrical contact such as a metal contact. The laser diode can comprise an electrical contact such as a metal contact overlying the epitaxial layers or overlying a transparent conductive oxide layer. The laser diode can comprise a second electrical contact underlying (lie epitaxial layers.

[0182]

[0148] The laser diode can comprise a substrate such as GaN, wherein the epitaxial layers overly the substrate. An electrical contact can underlie the substrate.

[0183]

[0149] A laser diode provided by the present disclosure can comprise a master oscillator section and a section, where the second section can comprise, for example, a second master oscillator, a power amplifier, a phase adjustment section, a refractive index adjustment section, a mirror section, a waveguide, or other optoelectronic element. For example, a second section can comprise a refractive index adjustment section configured to change the refractive index of an underlying epitaxial layer such as an active layer, to render an underlying epitaxial layer substantially transparent at the lasing wavelength. The epitaxial layers underlying the master oscillator section and the refractive index adjustment section can be the same.

[0184]

[0150] In a laser diode comprising a master oscillator section and a phase adjustment section, the laser diode can comprise a third section where the third section can comprise, for example, a second master oscillator, a power amplifier, a phase adjustment section, a refractive index adjustment section, a mirror section, a waveguide, or other optoelectronic element. For example, referring to FIG. 21, section 2106 can be a master oscillator section, and section 2107 can be a section configured to change the refractive index of one or more of the underlying epitaxial layers. For example, in the laser diode embodiments comprising a phase adjustment section, one of more to the phase adjustment sections can be replaced with a refractive index adjustment section.

[0185]

[0151] A laser diode provided by the present disclosure can comprise a master oscillator section; and a power amplifier section; wherein the master oscillator section and the power amplifier section are configured to be independently biased. The laser diode can be a multimode laser diode or a single mode laser diode. The laser diode can be a coupled cavity laser diode.

[0186]

[0152] The master oscillator section can comprise a single mode ridge waveguide laser diode. The single mode ridge waveguide laser diode can comprise an embedded Bragg grating.

[0187]

[0153] The power amplifier section can comprise a tapered ridge waveguide.

[0188]

[0154] The master oscillator section and the power amplifier section can comprise common epitaxial layers.

[0189]

[0155] The master oscillator section and the power amplifier section can overlie common epitaxial layers, where the master oscillator section comprises a first portion of the epitaxial layers and the power amplifier section comprises a second portion of the epitaxial layers.Attorney Docket No.: 61ZD-000510PC-407084

[0190] January 27, 2026

[0156] The master oscillator section can comprise a top electrical contact overlying a first portion of tire epitaxial layers and tire power amplifier section can comprise a second electrical contact overlying a second portion of tire epitaxial layers.

[0191]

[0157] The master oscillator section can comprise an electrical contact underlying the first portion of tire epitaxial layers and (lie power amplifier section can comprise an electrical contact underlying tire second portion of the epitaxial layers.

[0192]

[0158] A common electrical contact can underlie both the first portion and the second portion of the epitaxial layers.

[0193]

[0159] The laser diode can comprise a first electrical contact and a second electrical contact separated by an airgap.

[0194]

[0160] A portion of the epitaxial layers of the master oscillator section can be separated from a portion of the epitaxial layers of the power amplifier section by an airgap.

[0195]

[0161] The epitaxial layers of the master oscillator section can be separated from the epitaxial layers of the power amplifier section by an airgap.

[0196]

[0162] The epitaxial layers comprise a common active layer. The active layer associated with the master oscillator section can be separated from the active layer associated with the power amplifier section by an airgap. The active layer and the epitaxial layers overlying the active layer associated with the master oscillator section can be separated from the active layer and the epitaxial layers overlying the active layer associated with the power amplifier section by an airgap.

[0197]

[0163] The active layer associated with the master oscillator section can be separated from the active layer associated with the power amplifier section by a semiconductor material such as a regrown epitaxial layer.

[0198]

[0164] In a laser diode provided by the present disclosure, tire master oscillator section can comprise a first electrical contact overlying a first portion of epitaxial layers; and the power amplifier section can comprise a second electrical contact overlying second portion of the epitaxial layers. The first portion of tire epitaxial layers and the second portion of the epitaxial layers are contiguous.

[0199]

[0165] A single electrical contact can underlie the first portion of the epitaxial layers and the second portion of the epitaxial layers.

[0200]

[0166] A third electrical contact underlie tire first portion of tire epitaxial layers and a fourth electrical contact underlying the second portion of the epitaxial layers.

[0201]

[0167] A laser diode provided by the present disclosure can comprise: InAlGaN epitaxial layers; a first master oscillator section comprising a first portion of tire InAlGaN epitaxial layers, a first electrical contact overlying the first portion of the InAlGaN epitaxial layers, and a Bragg grating embedded within the uppermost cladding InAlGaN epitaxial layer; a phase adjustment section comprising a second portion of the InAlGaN epitaxial layers and a second electrical contact overlying the second portion of tire InAlGaN epitaxial layers; and a second master oscillator section comprising a third portion of die InAlGaN epitaxial layers and a third electrical contact overlying the third portionAttorney Docket No.: 61ZD-000510PC-407084

[0202] January 27, 2026 of the InAlGaN epitaxial layers, wherein each of the electrical contacts is configured to be independently addressable and is separated from an adjacent electrical contact by an airgap.

[0203]

[0168] A laser diode provided by the present disclosure can comprise: InAlGaN epitaxial layers; a master oscillator section comprising a first portion of the InAlGaN epitaxial layers, a first electrical contact and overlying die first portion of the InAlGaN epitaxial layers; an embedded Bragg grating embedded within the uppermost cladding InAlGaN epitaxial layer; and a power amplifier section comprising a second portion of the InAlGaN epitaxial layers and a second electrical contact overlying the second portion of die InAlGaN epitaxial layers, wherein each of the electrical contacts is configured to be independently addressable and is separated from an adjacent electrical contact by an airgap.

[0204]

[0169] A laser diode provided by the present disclosure can comprise: InAlGaN epitaxial layers; a first master oscillator section comprising a first portion of the InAlGaN epitaxial layers, a first electrical contact overlying the InAlGaN epitaxial layers, and a Bragg grating embedded in the uppermost cladding InAlGaN epitaxial layer; a phase adjustment section comprising a second portion of the InAlGaN epitaxial layers and a second electrical contact overlying the second portion of the InAlGaN epitaxial layers; a second master oscillator section comprising a third portion of the InAlGaN epitaxial layers and a third electrical contact overlying the third portion of the InAlGaN epitaxial layers; and a semiconductor amplifier section comprising a fourth portion of the InAlGaN epitaxial layers and having a fourth electrical contact overlying the fourth portion of the InAlGaN epitaxial layers, wherein each of the electrical contacts is configured to be independently addressable and is separated from an adjacent electrical contact by an airgap.

[0205]

[0170] A semiconductor wafer provided by die present disclosure can comprise one or more laser diodes provided by the present disclosure.

[0206]

[0171] A semiconductor wafer can comprise any suitable material and / or dimensions used in semiconductor manufacturing.

[0207]

[0172] A semiconductor wafer can comprise a wafer substrate and epitaxial layers that include a laser diode provided by the present disclosure at any stage in a laser diode manufacturing process.

[0208]

[0173] Laser diodes and laser diode arrays can be incorporated into combined photonic and electronic devices. For example, a laser diode array can be combined at the wafer level with arrayed waveguide gratings for use in devices such as, for example, optical multiplexers, microelectromechanical devices, and sensors.

[0209]

[0174] Laser diodes, laser diode arrays, and multijunction edge emitting laser diodes provided by the present disclosure are useful in a number of applications including, for example, quantum computing, quantum sensing, aerospace, defense, navigation and transportation, medicine and life sciences, industry and manufacturing, commercial and consumer apparatus, under underwater systems, oil and gas systems, and surveillance.Attorney Docket No.: 61ZD-000510PC-407084

[0210] January 27, 2026

[0175] Laser diodes, laser diode arrays, and multijunction edge emitting laser diodes provided by tire present disclosure are useful in quantum computing systems such as, for example, quantum sensors, quantum communication systems, quantum computers including trapped-ion quantum computers, photonic quantum computers, and superconducting quantum computers, and quantum encryption systems.

[0211]

[0176] Laser diodes, laser diode arrays, and multijunction edge emitting laser diodes provided by the present disclosure are useful in quantum sensors including, for example, atom interferometers, quantum gravimeters, quantum magnetometers, and quantum clocks.

[0212]

[0177] Laser diodes, laser diode arrays, and multijunction edge emitting laser diodes provided by the present disclosure are useful in aerospace systems including, for example, atomic clocks and ion clocks.

[0213]

[0178] Laser diodes, laser diode arrays, and multijunction edge emitting laser diodes provided by the present disclosure are useful in defense systems including, for example, gravity sensors, magnetic field sensors, electric field sensors, clocks, and LiDAR systems.

[0214]

[0179] Laser diodes, laser diode arrays, and multijunction edge emitting laser diodes provided by the present disclosure are useful in navigation systems including, for example, automotive navigation systems, satellite navigation systems, aviation systems, ground and ocean transportation systems, atomic clocks, and quantum navigation and synchronization systems.

[0215]

[0180] Laser diodes, laser diode arrays, and multijunction edge emitting laser diodes provided by the present disclosure are useful in medical and life science systems including, for example, medical diagnostic systems, medical monitoring systems, medical robotic systems, biomedical device systems, surgical system, automated prosthetic systems, microscopy, and imaging.

[0216]

[0181] Laser diodes, laser diode arrays, and multijunction edge emitting laser diodes provided by the present disclosure are useful in industrial systems such as, for example, manufacturing systems, additive manufacturing systems, semiconductor manufacturing systems, proximity sensors, fog and rain sensors, fire safety systems, water and food purification systems, and alignment systems.

[0217]

[0182] Laser diodes, laser diode arrays, and multijunction edge emitting laser diodes provided by tire present disclosure are useful in commercial and consumer systems including, for example, optical sensors, optical storage, virtual reality systems, augmented reality systems, free-space communication systems, and fiber-optic communication systems.

[0218]

[0183] Laser diodes, laser diode arrays, and multijunction edge emitting laser diodes provided by the present disclosure are useful in underwater systems including, for example, underwater ranging systems, underwater LiDAR systems, and underwater communications systems.

[0219]

[0184] Laser diodes, laser diode arrays, and multijunction edge emitting laser diodes provided by the present disclosure are useful in the oil and natural gas industry including for example, in discovery, drilling, extraction, transportation, and refining.Attorney Docket No.: 61ZD-000510PC-407084

[0220] January 27, 2026

[0185] Laser diodes, laser diode arrays, and multijunction edge emitting laser diodes provided by tire present disclosure are useful in surveillance systems.

[0221]

[0186] Laser diodes, laser diode arrays, and multijunction edge emitting laser diodes provided by tire present disclosure are useful in marine applications such as environmental monitoring, navigation, sensing, mapping, oceanography, communications, ranging and navigation.

[0222]

[0187] Laser diodes, laser diode arrays, and multijunction edge emitting laser diodes provided by the present disclosure are useful in environmental applications such as sensing, detection, monitoring, and analysis.

[0223] ASPECTS OF THE INVENTION

[0224]

[0188] The invention can be further defined by one or more of the following aspects.

[0225]

[0189] Aspect 1. A two-section single-mode coupled cavity laser diode comprising InAlGaN epitaxial layers, configured to provide wavelength tuning via the Vernier effect by independently adjusting the current in each of the two sections.

[0226]

[0190] Aspect 2. The two-section single-mode coupled cavity laser diode of aspect 1, wherein either one or both of the two sections comprise embedded gratings forming distributed feedback sections, wherein the embedded gratings can be continuous or sampled.

[0227]

[0191] Aspect 3. The two-section single-mode coupled cavity laser diode of aspect 2, wherein the embedded gratings are fabricated on tire p-side of the laser diode using alternating layers of indium tin oxide and SiCF.

[0228]

[0192] Aspect 4. The two-section single-mode coupled cavity laser diode of aspect 2, wherein the embedded gratings are fabricated on tire p-side of the laser diode using alternating layers of low-and high- Al content p-AlGaN fabricated using an etch and regrowth process.

[0229]

[0193] Aspect 5. The two-section single-mode coupled cavity laser diode of any one of aspects 2 to 4, wherein the laser diode comprises a tunnel junction and the embedded gratings are formed in alternating layers of n-AlGaN and SiO2or alternating layers of low and high Al content n-AlGaN.

[0230]

[0194] Aspect 6. The two-section single-mode coupled cavity laser diode of any one of aspects 1 and 5, wherein one section comprises a flared ridge waveguide configured to amplify the radiation produced from the other section without altering the longitudinal and spatial mode behavior.

[0231]

[0195] Aspect 7. The two-section single-mode coupled cavity laser diode of any one of aspects 1 and 6, comprising additional n sections (n >= 0) wherein the additional sections comprise a phase adjuster section, an SO A section, or a combination thereof.

[0232]

[0196] Aspect 8. The two-section single mode coupled cavity laser diode of aspect 7, comprising two grating DFB grating sections where the gratings utilize a sampled grating structure for improved Vernier control.

[0233]

[0197] Aspect 9. The two-section single mode coupled cavity laser diode of any one of aspects 1 and 8, comprising a passive waveguide section, wherein the passive waveguide section is formed byAttorney Docket No.: 61ZD-000510PC-407084

[0234] January 27, 2026 etching through the quantum wells followed by selective regrowth (such as with MOCVD) to reform tire waveguide layers without the quantum wells.

[0235]

[0198] Aspect 10. The two-section single mode coupled cavity laser diode of aspect 9, wherein tire passive waveguide section comprises identical epitaxial layers to the active sections and are configured to provide independent current control such that tire passive waveguide section can be biased to just below the lasing threshold (where gain = loss) to minimize optical absorption at tire lasing wavelength.

[0236]

[0199] Aspect 11. The two-section single mode coupled cavity laser diode of any one of aspects 1 and 8, wherein each of the two sections is defined by an airgap in the epitaxial waveguide layer and are formed by etching through the quantum wells.

[0237]

[0200] Aspect 12. The two-section single mode coupled cavity laser diode of any one of aspects 1 and 8, wherein each of the two sections is defined using an airgap only between the metal contacts and not within the epitaxial layers and utilize carrier-induced index contrast to achieve partial optical isolation between the sections.

[0238]

[0201] Aspect 13. The two-section single mode coupled cavity laser diode of any one of aspects 1-8 and 10, wherein each of the two sections is further isolated using a carrier-induced index mirror for increased optical isolation control.

[0239]

[0202] Aspect 14. A multijunction edge emitting laser comprising two or more vertically stacked InAlGaN laser diodes.

[0240]

[0203] Aspect 15. The multijunction edge emitting laser of aspect 14, wherein each of the InAlGaN laser diodes comprise an InAlGaN active region comprising a different In content than that of the other InAlGaN active regions.

[0241]

[0204] Aspect 16. A multijunction edge emitting laser as substantially shown in FIG. 27.

[0242]

[0205] Aspect 17. A laser diode array comprising a plurality of laser diodes, wherein each of the laser diodes is independently selected from the laser diode of any one of aspects 1-13 and 21-64.

[0243]

[0206] Aspect 18. The laser diode array of aspect 17, comprising an optical combiner, wherein each of the laser diodes is optically coupled to tire optical combiner.

[0244]

[0207] Aspect 19. The laser diode array of aspect 17, comprising an optical amplifier, wherein tire optical combiner is optically coupled to the semiconductor optical amplifier.

[0245]

[0208] Aspect 20. A laser diode array as substantially shown in FIG. 28.

[0246]

[0209] Aspect 21. A laser diode comprising an n-AlGaN cladding layer, wherein, the n-InAlGaN cladding layer comprises an embedded Bragg grating; and tire embedded Bragg grating comprises alternating lateral regions comprising n-InAlGaN and a low refractive index oxide.

[0247]

[0210] Aspect 22. The laser diode of aspect 21, wherein the low refractive index oxide is selected from indium tin oxide, indium zinc oxide, aluminum zinc oxide, indium tin zirconium oxide, indium gallium oxide, indium gallium zinc oxide, tin oxide, or zinc tin oxide.

[0248]

[0211] Aspect 23. A laser diode as substantially shown in FIG. 6.Attorney Docket No.: 61ZD-000510PC-407084

[0249] January 27, 2026

[0212] Aspect 24. A laser diode as substantially shown in FIG. 7.

[0250]

[0213] Aspect 25. A laser diode comprising a p-InAlGaN layer, wherein, the p-InAlGaN layer comprises an embedded Bragg grating; and the embedded Bragg grating comprises alternating lateral regions comprising a first p-InAlGaN and a second p-InAlGaN material, wherein the first p-InAlGaN material and (lie second p-InAlGaN material have a different Al content.

[0251]

[0214] Aspect 26. The laser diode of aspect 25, wherein the Al content of the first p-InAlGaN material is from 0% to 20%; and the Al content of the second p-InAlGaN material is from greater titan 0% to 20%.

[0252]

[0215] Aspect 27. The laser diode of aspect 25, comprising a metal contact layer overlying the p-InAlGaN layer.

[0253]

[0216] Aspect 28. A laser diode as substantially shown in FIG. 8.

[0254]

[0217] Aspect 29. A laser diode comprising: a tunnel junction; an n-lnAlGaN layer overlying the tunnel junction and comprising a first Al content; and an embedded Bragg grating; wherein, the embedded Bragg grating comprises separated lateral regions comprising a second n-InAlGaN material having a second Al content; and the second Al content is greater than the first Al content.

[0255]

[0001] Aspect 30. The laser diode of aspect 29, comprising a metal contact layer overlying the n-InAlGaN layer.

[0256]

[0219] Aspect 31. A laser diode as substantially shown in FIG. 9.

[0257]

[0220] Aspect 32. A laser diode comprising a first section, a second section, and an airgap, wherein, the first section and the second section comprise a continuous common waveguide layer; the first section comprises a first conductive oxide layer overlying the common waveguide layer and a first metal contact layer overlying the first conductive oxide layer; the second section comprises a second conductive oxide layer overlying the common waveguide layer and a second metal contact layer overlying the second conductive oxide layer; and tire airgap separates the first conductive oxide layer and the first metal contact layer from the second conductive oxide layer the second metal contact layer.

[0258]

[0221] Aspect 33. The laser diode of aspect 32, wherein the first section is a master oscillator and tire second section is a power amplifier.

[0259]

[0222] Aspect 34. The laser diode of aspect 32, wherein the power amplifier comprises a tapered waveguide.

[0260]

[0223] Aspect 35. The laser diode of aspect 32, wherein the first conductive oxide layer and the second conductive oxide layer comprise tire same material.

[0261]

[0224] Aspect 36. The laser diode of aspect 32, wherein the first metal contact layer and the second metal contact layer comprise the same material.

[0262]

[0225] Aspect 37. The laser diode of aspect 32, wherein the airgap has a lateral dimension of from 1 pm to 20 pm.

[0263]

[0226] Aspect 38. A laser diode as substantially shown in FIG. 13.Attorney Docket No.: 61ZD-000510PC-407084

[0264] January 27, 2026

[0227] Aspect 39. A laser diode, wherein, the laser diode has a sampled grating distributed Bragg reflector configuration configured to operate in a wavelength range from 200 nm to 550 nm such as from 350 nm to 550 nm; and the active region comprises InAlGaN.

[0265]

[0228] Aspect 40. The laser diode of aspect 39, wherein the laser diode comprises a first section, a second section, and a third section between the first section and the second section.

[0266]

[0229] Aspect 41. The laser diode of aspect 39, wherein the first section and the second section comprise a common continuous first confinement layer.

[0267]

[0230] Aspect 42. The laser diode of aspect 39, wherein the first section and the second section comprise a discontinuous active region layer, discontinuous overlying confinement layers, and discontinuous overlying p-type cladding layer.

[0268]

[0231] Aspect 43. The laser diode of aspect 39, wherein the third section comprises a regrowth layer.

[0269]

[0232] Aspect 44. The laser diode of aspect 39, wherein the regrowth layer comprises InAlGaN of each a p-type upper cladding layer, an upper confinement layer, and waveguide region without InGaN multi-quantum wells.

[0270]

[0233] Aspect 45. A laser diode as substantially shown in FIG. 16.

[0271]

[0234] Aspect 46. A laser diode, wherein, the laser diode has a sampled grating distributed Bragg reflector configuration configured to operate in a wavelength range from 200 nm to 550 nm such as from 350 nm to 550 nm; the laser diode comprises a first active section, a second active section and a passive section between the first active section and the second active section; and the first active section, the second active section and the passive section comprise a common continuous InAlGaN active layer.

[0272]

[0235] Aspect 47. The laser diode of aspect 46, wherein each of the first active section, the second active section and the passive section comprise tire same continuous epitaxial layers.

[0273]

[0236] Aspect 48. The laser diode of aspect 46, wherein, a voltage applied to the passive section provides a current flowing through the passive section that is below the lasing threshold of tire passive section; and is substantially transparent at a lasing wavelength of the first active section and the second active section.

[0274]

[0237] Aspect 49. A laser diode as substantially shown in FIG. 17.

[0275]

[0238] Aspect 50. A laser diode, wherein, the laser diode has a sampled grating distributed Bragg reflector configuration configured to operate in a wavelength range from 200 nm to 550 nm such as from 350 nm to 550 nm; the laser diode comprises a first active section and a second active section; each of the first active section and tire second active section comprises a common continuous AlInGaN active layer; and at least one of the first active section and the second active section comprises a Bragg grating layer.Attorney Docket No.: 61ZD-000510PC-407084

[0276] January 27, 2026

[0239] Aspect 51. The laser diode of aspect 50, wherein the Bragg grating layer comprises alternating lateral regions comprising high and low Al content p-InAlGaN, high and low Al content n-InAlGaN, and AlGaN and SiOi.

[0277]

[0240] Aspect 52. The laser diode of aspect 50, wherein the Bragg grating layer overlies a p-type cladding layer and underlies a metal contact layer.

[0278]

[0241] Aspect 53. The laser diode of aspect 50, wherein the laser diode comprises an active phase adjustment section disposed between the first active section and the second active section.

[0279]

[0242] Aspect 54. The laser diode of aspect 50, wherein the laser diode comprises a semiconductor optical amplifier section.

[0280]

[0243] Aspect 55. A laser diode as substantially shown in FIG. 18.

[0281]

[0244] Aspect 56. A laser diode comprising: a first section, a second section, and a common continuous InAlGaN active layer; wherein, the first section comprises a first electrical contact; and the second section comprises a second electrical contact; and a third section electrically isolating die first electrical contact and the second electrical contact; wherein the third section comprises an airgap, an electrical insulator, or a carrier induced index mirror.

[0282]

[0245] Aspect 57. The laser diode of aspect 56, wherein, third section comprises an airgap; and the third section has a lateral dimension less than a lasing wavelength of the laser diode.

[0283]

[0246] Aspect 58. The laser diode of aspect 56, wherein, the first section has a first lateral dimension; the second section has a second lateral dimension; and the first lateral dimension is greater than the second lateral dimension.

[0284]

[0247] Aspect 59. The laser diode of aspect 56, wherein, the third section comprises an electrical insulator; and the third section has a lateral dimension.

[0285]

[0248] Aspect 60. The laser diode of aspect 56, wherein, the third section comprises a carrier induced index mirror; and the carrier induced index mirror is configured to induce a change in the refractive index of tire third active region.

[0286]

[0249] Aspect 61. A laser diode as substantially shown in FIG. 21.

[0287]

[0250] Aspect 62. A laser diode as substantially shown in FIG. 22.

[0288]

[0251] Aspect 63. A laser diode as substantially shown in FIG. 26.

[0289]

[0252] Aspect 64. The laser diode of aspect 56, wherein the carrier-induced index mirror is configured to induce a change in the refractive index of tire underlying epitaxial layers.

[0290]

[0253] Aspect 65. An optoelectronic component comprising the laser diode of any one of aspects 1-13 and 21-64.

[0291]

[0254] Aspect 66. An optoelectronic system comprising the laser diode of airy one of aspects 1-13 and 21-64, the multijunction edge emitting laser of any one of aspects 14-16, or tire laser diode array of any one of aspects 17-20.Attorney Docket No.: 61ZD-000510PC-407084

[0292] January 27, 2026

[0255] Aspect 67. An integrated optoelectronic device comprising a combination of the laser diode of any one of aspects 1-13 and 21-64 or the laser diode array of any one of aspects 17-20, and one or more electronic components.

[0293]

[0256] Aspect 68. A system comprising the laser diode of any one of aspects 1-13 and 21-64, the multijunction edge emitting laser of any one of aspects 14-16, or the laser diode array of any one of aspects 17-20, the optoelectronic component of any one of aspect 65, or the integrated optoelectronic device of any one of aspect 67.

[0294]

[0257] Aspect 69. The system of aspect 68, wherein the system comprises a quantum computing system.

[0295]

[0258] Aspect 70. The system of aspect 69, wherein the quantum computing system comprises a quantum sensor, a quantum communication system, a quantum computer, or a quantum encryption system.

[0296]

[0259] Aspect 71. The system of aspect 70, wherein the quantum computer comprises a trapped-ion quantum computer, a photonic quantum computer, or a superconducting quantum computer.

[0297]

[0260] Aspect 72. The system of aspect 69, wherein the quantum sensor comprises an atom interferometer, a quantum gravimeter, a quantum magnetometer, or a quantum clock.

[0298]

[0261] Aspect 73. The system of aspect 68, wherein the system comprises an aerospace system.

[0299]

[0262] Aspect 74. The system of aspect 73, wherein the aerospace system comprises an atomic clock, or an ion clock.

[0300]

[0263] Aspect 75. The system of aspect 68, wherein the system comprises a defense system.

[0301]

[0264] Aspect 76. The system of aspect 75, wherein the defense system comprises a gravity sensor, a magnetic field sensor, an electric field sensor, a time sensor, or a LiDAR system.

[0302]

[0265] Aspect 77. The system of aspect 68, wherein the system comprises a navigation system.

[0303]

[0266] Aspect 78. The system of aspect 77, wherein the navigation system comprises an automotive navigation system, a satellite navigation system, a transportation navigation system, an atomic clock, or a quantum navigation and synchronization system.

[0304]

[0267] Aspect 79. The system of aspect 68, wherein the system comprises a medical system.

[0305]

[0268] Aspect 80. The system of aspect 79, wherein the medical system comprises a medical diagnostic system, a medical monitoring system, advanced robotic system, a biomedical device system, a surgical system, a brain-driven prosthetic automated system, or a microscopy system, an imaging system.

[0306]

[0269] Aspect 81. The system of aspect 69, wherein the system comprises an industrial system.

[0307]

[0270] Aspect 82. The system of aspect 81, wherein the industrial system comprises a manufacturing system, an additive manufacturing system, a semiconductor manufacturing system, a proximity sensor, a fog and rain sensor, a fire safety system, a water and food purification system, or an alignment system.Attorney Docket No.: 61ZD-000510PC-407084

[0308] January 27, 2026

[0271] Aspect 83. The system of aspect 68, wherein the system comprises a commercial or consumer system.

[0309]

[0272] Aspect 84. The system of aspect 83, wherein the commercial or consumer system comprises an optical sensor, optical storage, a virtual reality system, an augmented reality system, a free-space communication system, or a fiber optic communication system.

[0310]

[0273] Aspect 85. The system of aspect 68, wherein the system comprises an underwater system.

[0311]

[0274] Aspect 86. The system of aspect 85, wherein the underwater system comprises an underwater ranging system, an underwater LiDAR system, or an underwater communications system.

[0312]

[0275] Aspect 87. The system of aspect 68, wherein the system comprises an oil and gas system.

[0313]

[0276] Aspect 88. 1'he system of aspect 68, wherein the system comprises a surveillance system.

[0314]

[0277] Aspect 69. The system of aspect 68, wherein the system comprises a biomedical system.

[0315]

[0278] Aspect 70. The system of aspect 68, wherein the system comprises a medical system.

[0316]

[0279] Aspect 71. The system of aspect 70, wherein the medical system comprises a medical diagnostic system, a medical monitoring system, advanced robotic system, a biomedical device system, a surgical system, a brain-driven prosthetic automated system, a microscopy system, or an imaging system.

[0317]

[0280] Aspect 72. The system of aspect 68, wherein the system comprises a biotech system.

[0318]

[0281] The invention can be further defined by one or more of the following aspects.

[0319]

[0282] Aspect 1 A. A laser diode comprising: a first section having a first electrical contact; and a second section having a second electrical contact; wherein, the first section and the second section comprise the same InAlGaN epitaxial layers; the first electrical contact overlies a first portion of the InAlGaN epitaxial layers; and the second electrical contact overlies a second portion of the InAlGaN epitaxial layers.

[0320]

[0283] Aspect 2A. The laser diode of aspect 1A, wherein each of the first electrical contact and tire second electrical contact comprise a metal.

[0321]

[0284] Aspect 3A. The laser diode of aspect 1 A, wherein tire first electrical contact is electrically isolated from tire second electrical contact.

[0322]

[0285] Aspect 4A. The laser diode of any one of aspects 1 A and 2A, comprising: a third electrical contact underlying the first portion of the InAlGaN epitaxial layers; and a fourth electrical contact underlying the second portion of tire InAlGaN epitaxial layers.

[0323]

[0286] Aspect 5A. The laser diode of aspect 3A, wherein each of the third electrical contact and the fourth electrical contact comprise a metal.

[0324]

[0287] Aspect 6A. The laser diode of any one of aspects 4A and 5A, wherein tire third electrical contact is electrically isolated from the fourth electrical contact.Attorney Docket No.: 61ZD-000510PC-407084

[0325] January 27, 2026

[0288] Aspect 7A. The laser diode of any one of aspects 1 to 6, wherein, tire first section comprises an embedded Bragg grating; the second section comprises an embedded Bragg grating; or both the first section and tire second section comprise an embedded Bragg grating.

[0326]

[0289] Aspect 8 A. The laser diode of aspect 7 A, wherein the embedded Bragg grating is a continuous grating.

[0327]

[0290] Aspect 9A. The laser diode of aspect 7A, wherein the embedded Bragg grating is a sampled grating.

[0328]

[0291] Aspect 10A. The laser diode of aspect 7A, wherein an uppermost epitaxial cladding layer comprises the embedded Bragg grating.

[0329]

[0292] Aspect 11 A. The laser diode of aspect 10A, wherein tire uppermost epitaxial cladding layer is a n-InAlGaN layer.

[0330]

[0293] Aspect 12A. 1'he laser diode of aspect 10A, wherein die uppermost epitaxial cladding layer is a p-InAlGaN layer.

[0331]

[0294] Aspect 13 A. The single mode coupled cavity laser diode of aspect 7 A, wherein the embedded Bragg grating is disposed on a p-side of the laser diode.

[0332]

[0295] Aspect 14A. The laser diode of aspect 7A, wherein the embedded Bragg grating comprises alternating lateral regions of a low refractive index material and a high refractive index material.

[0333]

[0296] Aspect 15A. The laser diode of aspect 14A, wherein the alternating lateral regions are disposed orthogonal to the longitudinal direction of the laser cavity.

[0334]

[0297] Aspect 16A. The laser diode of aspect 14A, wherein the alternating lateral regions comprise alternating lateral regions of a transparent conductive oxide and Si( K

[0335]

[0298] Aspect 17A. The laser diode of aspect 16A, wherein the transparent conductive oxide comprises indium tin oxide.

[0336]

[0299] Aspect 18A. The laser diode of aspect 14A, wherein the alternating regions comprise alternating lateral regions of low Al-content p-InAlGaN and high Al-content p-InAlGaN.

[0337]

[0300] Aspect 19 A. The laser diode of aspect 14A, wherein the alternating regions comprise alternating lateral regions of n-InAlGaN and SiOi.

[0338]

[0301] Aspect 20A. The laser diode of aspect 14A, wherein the alternating regions comprise alternating lateral regions of low Al-content n-InAlGaN and high Al-content n-InAlGaN.

[0339]

[0302] Aspect 21. The laser diode of any one of aspects 1 to 20, wherein tire epitaxial layers comprise: an n-InAlGaN layer; an active layer overlying the n-InAlGaN layer; and a p-InAlGaN layer overlying the active layer.

[0340]

[0303] Aspect 22A. The laser diode of any one of aspects 1A to 20 A, wherein the epitaxial layers comprise: a first n-InAlGaN layer; an active layer overlying the n-InAlGaN layer; an p-InAlGaN layer overlying the active layer; a tunnel junction overlying the p-InAlGaN layer; and a second n-InAlGaN layer overlying the tunnel junction.Attorney Docket No.: 61ZD-000510PC-407084

[0341] January 27, 2026

[0304] Aspect 23A. The laser diode of aspect 22A, wherein the active layer comprises InGaN.

[0342]

[0305] Aspect 24A. The laser diode of aspect 22A, wherein the active layer comprises multiple quantum wells.

[0343]

[0306] Aspect 25A. The laser diode of aspect 22A, comprising a transparent conductive oxide layer overlying tire epitaxial layers and underlying the first electrical contact and tire second electrical contact.

[0344]

[0307] Aspect 26A. The laser diode of aspect 25A, wherein tire transparent conductive oxide comprises indium tin oxide.

[0345]

[0308] Aspect 27A. The laser diode of any one of aspects 1 A to 26A, comprising a substrate underlying the InAlGaN epitaxial layers.

[0346]

[0309] Aspect 28A. 1'he laser diode of aspect 27A, wherein die substrate comprises n- GaN.

[0347]

[0310] Aspect 29A. The laser diode of any one of aspects 1A to 28A comprising: a third electrical contact underlying the first portion of the InAlGaN epitaxial layers and a first portion of the substrate; and a fourth electrical contact underlying the second portion of the InAlGaN epitaxial layers and a second portion of the substrate.

[0348]

[0311] Aspect 30A. The laser diode of aspect 29A, wherein each of the third electrical contact and the fourth electrical contact comprise a metal.

[0349]

[0312] Aspect 31 A. The laser diode of any one of aspects 29 A to 30 A, wherein the third electrical contact is electrically isolated from the fourdr electrical contact.

[0350]

[0313] Aspect 32 A. The laser diode of any one of aspects 1A to 31 A, wherein the first section comprises a ridge waveguide master oscillator.

[0351]

[0314] Aspect 33A. The laser diode of any one of aspects 1A to 31A, wherein tire first section comprises a ridge waveguide master oscillator and an embedded Bragg grating.

[0352]

[0315] Aspect 34. The laser diode of any one of aspects 1 to 33, wherein the second section comprises an optoelectronic element such as a power amplifier, a waveguide, a diode laser, a phase section, or a mirror section.

[0353]

[0316] Aspect 34 A. The laser diode of any one of aspects 1 to 33, wherein the second section comprises a ridge waveguide master oscillator.

[0354]

[0317] Aspect 35 A. The laser diode of any one of aspects 1A to 33 A, wherein the second section comprises a ridge waveguide master oscillator and an embedded Bragg grating.

[0355]

[0318] Aspect 36A. The laser diode of any one of aspects 1A to 33 A, wherein the second section comprises a flared ridge waveguide power amplifier.

[0356]

[0319] Aspect 37A. The laser diode of aspect 36A, wherein tire flared ridge waveguide power amplifier is configured to amplify radiation emitted by the first section without altering the longitudinal and spatial mode characteristics of the radiation emitted by the first section.Attorney Docket No.: 61ZD-000510PC-407084

[0357] January 27, 2026

[0320] Aspect 38 A. The laser diode of any one of aspects 1A to 37, A wherein tire single mode coupled cavity laser diode comprises a phase adjustment section, a semiconductor amplifier section, or a phase adjustment section and a semiconductor amplifier section.

[0358]

[0321] Aspect 39A. The laser diode of any one of aspects 1A to 38A, comprising an airgap separating a portion of tire first section and a portion of the second section.

[0359]

[0322] Aspect 40A. The laser diode of aspect 39A, wherein tire airgap separates the first electrical contact and tire second electrical contact.

[0360]

[0323] Aspect 41 A. The laser diode of any one of aspects 39 A to 40A, wherein the airgap does not separate tire epitaxial layers of the first section and the epitaxial layers of the second section.

[0361]

[0324] Aspect 42A. The laser diode of any one of aspects 39 A to 41 A, comprising a transparent conductive oxide layer overlying the InAlGaN epitaxial layers; wherein the airgap separates the portion of the transparent conductive oxide layer underlying the first electrical contact from the portion of die transparent conductive oxide layer underlying the second electrical contact.

[0362]

[0325] Aspect 43A. The laser diode of any one of aspects 39A to 42A, wherein the airgap separates some of the epitaxial layers of the first section from some of the epitaxial layers of the second section.

[0363]

[0326] Aspect 44A. The laser diode of any one of aspects 39A to 42A, wherein the airgap separates the epitaxial layers of the first section from the epitaxial layers of the second section.

[0364]

[0327] Aspect 45A. The laser diode of any one of aspects 39A to 42A, wherein, the epitaxial layers comprise an active layer; and the airgap separates the active layer of the first section from the active layer of the second section are separated by an airgap.

[0365]

[0328] Aspect 46 A. The laser diode of any one of aspects 39 A to 42 A, wherein the epitaxial layers comprise an active layer and epitaxial layers overlying the active layer; and the airgap separates the active layer and tire epitaxial layers overlying tire active layer of the first section from tire active layer and the epitaxial layers overlying the active layer of the second section.

[0366]

[0329] Aspect 47A. The laser diode of any one of aspects 39A to 42A, wherein, tire epitaxial layers comprise an active layer; and the active layer of the first section and tire active layer of the second section are separated by InAlGaN.

[0367]

[0330] Aspect 48A. The laser diode of aspect 1 A, wherein, tire first section is a first master oscillator; tire second section is a power amplifier; and comprising air airgap disposed between the first electrical contact and tire second electrical contact.

[0368]

[0331] Aspect 49 A. The laser diode of aspect 48 A, wherein tire first section comprises an embedded Bragg grating.

[0369]

[0332] Aspect 50A. The laser diode of aspect 48A, comprising a carrier-induced index mirror disposed between the first electrical contact and tire second electrical and separated from the first electrical contact by a first airgap and from the second electrical contact by a second airgap.Attorney Docket No.: 61ZD-000510PC-407084

[0370] January 27, 2026

[0333] Aspect 51 A. The laser diode of aspect 48A, comprising a second active section and a semiconductor optical amplifier section, wherein an airgap is disposed between adjacent sections, wherein, each of the sections independently comprises an electrical contact; and the electrical contacts of adjacent sections are separated by an airgap.

[0371]

[0334] Aspect 52A. The laser diode of aspect 48A, wherein the airgap separates the first portion of the InAlGaN epitaxial layers and the second portion of the InAlGaN epitaxial layers.

[0372]

[0335] Aspect 53 A. The laser diode of aspect 48 A, wherein tire epitaxial layers comprise an active layer; and the airgap separates the active layer and the epitaxial layers overlying the active layer of the first portion from the active layer and the epitaxial layers overlying the active layer of the second portion.

[0373]

[0336] Aspect 54A. A laser diode comprising: InAlGaN epitaxial layers; a first master oscillator section comprising a first portion of the InAlGaN epitaxial layers, a first electrical contact overlying the first portion of the InAlGaN epitaxial layers, and a Bragg grating embedded within the uppermost cladding InAlGaN epitaxial layer; a phase adjustment section comprising a second portion of the InAlGaN epitaxial layers and a second electrical contact overlying the second portion of the InAlGaN epitaxial layers; and a second master oscillator section comprising a third portion of the InAlGaN epitaxial layers and a third electrical contact overlying the third portion of the InAlGaN epitaxial layers, wherein each of the electrical contacts is configured to be independently addressable and is separated from an adjacent electrical contact by an airgap.

[0374]

[0337] Aspect 55A. A laser diode comprising: InAlGaN epitaxial layers; a master oscillator section comprising a first portion of the InAlGaN epitaxial layers, a first electrical contact and overlying the first portion of the InAlGaN epitaxial layers; an embedded Bragg grating embedded within the uppermost cladding InAlGaN epitaxial layer; and a power amplifier section comprising a second portion of the InAlGaN epitaxial layers and a second electrical contact overlying tire second portion of tire InAlGaN epitaxial layers, wherein each of the electrical contacts is configured to be independently addressable and is separated from an adjacent electrical contact by an airgap.

[0375]

[0338] Aspect 56A. A laser diode comprising: InAlGaN epitaxial layers; a first master oscillator section comprising a first portion of tire InAlGaN epitaxial layers, a first electrical contact overlying tire InAlGaN epitaxial layers, and a Bragg grating embedded in tire uppermost cladding InAlGaN epitaxial layer; a phase adjustment section comprising a second portion of the InAlGaN epitaxial layers and a second electrical contact overlying the second portion of tire InAlGaN epitaxial layers; a second master oscillator section comprising a third portion of the InAlGaN epitaxial layers and a third electrical contact overlying the third portion of the InAlGaN epitaxial layers; and a semiconductor amplifier section comprising a fourth portion of the InAlGaN epitaxial layers and having a fourth electrical contact overlying the fourth portion of the InAlGaN epitaxial layers, wherein each of the electrical contacts is configured to be independently addressable and is separated from an adjacent electrical contact by an airgap.Attorney Docket No.: 61ZD-000510PC-407084

[0376] January 27, 2026

[0339] Aspect 57A. A laser diode comprising an embedded Bragg grating.

[0377]

[0340] Aspect 58A. The laser diode of aspect 57A, wherein the laser diode is configured to operate as a single mode laser.

[0378]

[0341] Aspect 59.A The laser diode of aspect 57A, wherein the laser diode is configured to operate as a multimode laser.

[0379]

[0342] Aspect 60A. The laser diode of any one of aspects 57A to 59A, wherein the laser diode is a ridge waveguide laser diode.

[0380]

[0343] Aspect 61 A. The laser diode of any one of aspects 57 A to 60A, wherein the embedded Bragg grating is a continuous grating.

[0381]

[0344] Aspect 62A. The laser diode of any one of aspects 57A to 60A, wherein the embedded Bragg grating is a sampled grating.

[0382]

[0345] Aspect 63A. 1'he laser diode of any one of aspects 57A to 62A, wherein the uppermost epitaxial cladding layer is an n-InAlGaN layer.

[0383]

[0346] Aspect 64A. The laser diode of any one of aspects 57A to 62A, wherein the uppermost epitaxial cladding layer is a p-InAlGaN layer.

[0384]

[0347] Aspect 65A. The laser diode of any one of aspects 57A to 62A, wherein the embedded Bragg grating is disposed on a p-side of the laser diode.

[0385]

[0348] Aspect 66A. The laser diode of any one of aspects 57A to 65A, wherein the embedded Bragg grating comprises alternating lateral regions of a low refractive index material and a high refractive index material.

[0386]

[0349] Aspect 67A. The laser diode of aspect 66, A wherein the alternating lateral regions are disposed orthogonal to the longitudinal direction of the laser cavity.

[0387]

[0350] Aspect 68A. The laser diode of any one of aspects 66A to 67A, wherein the alternating lateral regions comprise alternating lateral regions of a transparent conductive oxide and SiO2.

[0388]

[0351] Aspect 69A. The laser diode of aspect 68, wherein the transparent conductive oxide comprises indium tin oxide.

[0389]

[0352] Aspect 70A. The laser diode of any one of aspects 66A to 67A, wherein the alternating regions comprise alternating lateral regions of low Al-content p-InAlGaN and a high Al-content p-InAlGaN.

[0390]

[0353] Aspect 71 A. The laser diode of any one of aspects 66A to 67A, wherein tire alternating regions comprise alternating lateral regions of n-InAlGaN and SiO2.

[0391]

[0354] Aspect 72A. The laser diode of any one of aspects 66A to 67A, wherein the alternating regions comprise alternating lateral regions of low Al-content n-InAlGaN and a high Al-content n-InAlGaN.

[0392]

[0355] Aspect 73A. The laser diode of any one of aspects 57A to 72A, comprising epitaxial layers, wherein the Bragg grating is embedded within an uppermost epitaxial cladding layer.Attorney Docket No.: 61ZD-000510PC-407084

[0393] January 27, 2026

[0356] Aspect 74A. The laser diode of any one of aspects 57A to 73A, comprising epitaxial layers.

[0394]

[0357] Aspect 75 A. The laser diode of aspect 74A, wherein the epitaxial layers comprise InAlGaN.

[0395]

[0358] Aspect 76A. The laser diode of aspect 74A, wherein the epitaxial layers comprise: an n-InAlGaN layer; an active layer overlying the n-InAlGaN layer; and a p-InAlGaN layer overlying the active layer.

[0396]

[0359] Aspect 77A. The laser diode of aspect 74A, wherein the epitaxial layers comprise: a first n-InAlGaN layer; an active layer overlying the n-InAlGaN layer: an p-InAlGaN layer overlying the active layer; a tunnel junction overlying the p-InAlGaN layer; and a second n-InAlGaN layer overlying the tunnel junction.

[0397]

[0360] Aspect 78 A. 1'he laser diode of aspect 77 A, wherein die active layer comprises InGaN.

[0398]

[0361] Aspect 79A. The laser diode of any one of aspects 77A to 78A, wherein the active layer comprises multiple quantum wells.

[0399]

[0362] Aspect 80A. The laser diode of any one of aspects 74A to 79A, comprising a transparent conductive oxide layer overlying the epitaxial layers and underlying the first electrical contact and the second electrical contact.

[0400]

[0363] Aspect 81 A. The laser diode of aspect 80, wherein the transparent conductive oxide comprises indium tin oxide.

[0401]

[0364] Aspect 82 A. The laser diode of any one of aspects 74A to 81 A, comprising a first electrical contact overlying die epitaxial layers.

[0402]

[0365] Aspect 83 A. The laser diode of any one of aspects 74 to 82, comprising a second electrical contact underlying the epitaxial layers.

[0403]

[0366] Aspect 84 A. The laser diode of any one of aspects 74 to 83, comprising a substrate underlying the epitaxial layers.

[0404]

[0367] Aspect 85A. The laser diode of aspect 84, wherein the substrate comprises n-GaN.

[0405]

[0368] Aspect 86A. The laser diode of any one of aspects 84A to 86A, comprising an electrical contact underlying die substrate.

[0406]

[0369] Aspect 87A. A laser diode comprising: a master oscillator section; and a power amplifier section; wherein the master oscillator section and die power amplifier section are configured to be independently biased.

[0407]

[0370] Aspect 88A. The laser diode of aspect 87A, wherein die master oscillator section comprises a single mode ridge waveguide laser diode.

[0408]

[0371] Aspect 89A. The laser diode of aspect 87A, wherein die master oscillator section comprises a multimode ridge waveguide laser diode.Attorney Docket No.: 61ZD-000510PC-407084

[0409] January 27, 2026

[0372] Aspect 90A. The laser diode of any one of aspects 87A to 89A, wherein the master oscillator section laser diode comprises an embedded Bragg grating.

[0410]

[0373] Aspect 91 A. The laser diode of any one of aspects 87 A to 90A, wherein the power amplifier section comprises a tapered ridge waveguide.

[0411]

[0374] Aspect 92A. The laser diode of any one of aspects 87A to 90A, wherein die master oscillator section comprises a first electrical contact and a first portion of epitaxial layers; and the power amplifier section comprises a second electrical contact and second portion of the epitaxial layers.

[0412]

[0375] Aspect 93A. The laser diode of aspect 92A, wherein die first electrical contact and the second electrical contact are separated by an airgap.

[0413]

[0376] Aspect 94A. The laser diode of any one of aspects 92A to 93A, wherein the first portion of the epitaxial layers and the second portion of epitaxial layers are separated by an airgap.

[0414]

[0377] Aspect 95A. The laser diode of any one of aspects 92A to 94A, wherein the first portion of the epitaxial layers comprise a first portion of an active layer; and the second portion of the epitaxial layers comprise a second portion of the active layer,

[0415]

[0378] Aspect 96A. The laser diode of aspect 95A, wherein the first portion of the active layer and the second portion of the active layer are separated by an airgap.

[0416]

[0379] Aspect 97A. The laser diode of aspect 95 A, wherein first portion of the active layer and the first portion of the epitaxial layers overlying the first portion of the active layer and the second first portion of the active layer and the second first portion of the epitaxial layers overlying the second first portion of the active layer are separated by an airgap.

[0417]

[0380] Aspect 98A. The laser diode of aspect 95A, wherein the first portion of the active layer and the second portion of the active layer are separated by a semiconductor material.

[0418]

[0381] Aspect 99A. The laser diode of aspect 95A, wherein the first portion of the active layer and the second portion of tire active layer are separated by a regrown epitaxial layer.

[0419]

[0382] Aspect 100A. The laser diode of any one of aspects 87A to 99A, wherein the master oscillator section comprises a first electrical contact overlying a first portion of epitaxial layers; and tire power amplifier section comprises a second electrical contact overlying second portion of the epitaxial layers.

[0420]

[0383] Aspect 101A. The laser diode of aspect 100A, wherein the first portion of the epitaxial layers and tire second portion of the epitaxial layers are contiguous.

[0421]

[0384] Aspect 102A. The laser diode of any one of aspects 100A to 101A, comprising a third electrical contact underlying tire first portion of the epitaxial layers and tire second portion of the epitaxial layers.

[0422]

[0385] Aspect 103A. The laser diode of aspect 102A, wherein comprising a third electrical contact underlying the first portion of the epitaxial layers and a fourth electrical contact underlying the second portion of the epitaxial layers.Attorney Docket No.: 61ZD-000510PC-407084

[0423] January 27, 2026

[0386] Aspect 104 A. A multijunction edge emitting laser diode comprising: a first laser diode according to any one of aspects 1A to 103A; and a second laser diode according to aspect 1A, wherein the second laser diode overlies the first laser diode; and the first laser diode and the second laser diode are configured to be independently driven.

[0424]

[0387] Aspect 105A. The multijunction edge emitting laser diode of aspect 104A, wherein the epitaxial layers comprise an active layer; and the airgap separates the active layer and epitaxial layers overlying the active layer.

[0425]

[0388] Aspect 106A. An array of laser diodes of any one of aspects 1A to 103A.

[0426]

[0389] Aspect 107A. A semiconductor wafer comprising the laser diode of any one of aspects 1A to 103A, the multijunction edge emitting laser diode of any one of aspects 104A to 105A: or the array of laser diodes of aspect 106 A.

[0427]

[0390] Aspect 108A. An optoelectronic system comprising the laser diode of any one of aspects 1A to 103A, the multijunction edge emitting laser diode of any one of aspects 104A to 105A: or the array of laser diodes of aspect 106A.

[0428]

[0391] Aspect 109A. The optoelectronic system of aspect 108, wherein the optoelectronic system is used for quantum computing, quantum sensing, aerospace, defense, navigation and transportation, medicine and life sciences, industry and manufacturing, commercial and consumer apparatus, under underwater systems, oil and gas systems, or surveillance.

[0429]

[0392] Aspect 110 A. A laser diode comprising a first section and a second section overlying common epitaxial layers, wherein the first section comprises a master oscillator and the second section is configured to change the refractive index of one or more of the underlying epitaxial layers.

[0430]

[0393] Aspect 111 A. The laser diode of claim 110A, wherein the second section is configured to render the refractive index of one or more of the epitaxial layers such as the active layer, transparent to a lasing wavelength.

[0431]

[0394] Aspect 112A. The laser diode of any one of claims 110A and 111 A, comprising a third section, wherein tire third section is a second master oscillator, a power amplifier, a phase adjustment section, a mirror, a waveguide, or other optoelectronic component.

[0432]

[0395] Aspect 113A. The laser diode of any one of claims 110A and 112A, wherein the first section comprises an embedded Bragg grating.

[0433]

[0396] Aspect 114A. The laser diode of any one of claims 110A and 113A, wherein tire first section and the second section are configmed to be independently biased.

[0434] EXAMPLES

[0435]

[0397] Embodiments provided by the present disclosure are further illustrated by reference to the following examples, which describe details of laser diodes, properties of the laser diodes, and methods of fabricating the laser diodes provided by the present disclosure. It will be apparent to those skilledAttorney Docket No.: 61ZD-000510PC-407084

[0436] January 27, 2026 in the art that many modifications, both to materials, and methods, may be practiced without departing from the scope of the disclosure.

[0437] Example 1

[0438]

[0398] To obtain the test results for the laser diodes provided herein, with the exception of the DFB MOPA LD, the laser diodes were operated in quasi-continuous wave (QCW) pulsed mode with a pulse width of 100 ps with a 20 ms period (0.5% duty cycle).

[0439]

[0399] For the DFB MOPA LD results, the laser diode was operated in QCW mode with a l ps pulse width with a 14 ps period (~7% duty cycle).

[0440]

[0400] Results for fabricated laser diodes according to the present disclosure are present in FIGS.

[0441] 5, 11, 12A, 12B, 12C, and 30-32. A cross-sectional SEM view of an embedded Bragg grating is shown in FIG. 29.

[0442]

[0401] Finally, it should be noted that there are alternative ways of implementing the embodiments disclosed herein. Accordingly, the present embodiments are to be considered as illustrative and not restrictive. Furthermore, the claims are not to be limited to the details given herein and are entitled to their full scope and equivalents thereof.

Claims

1. Attorney Docket No.: 61ZD-000510PC-407084January 27, 2026 CLAIMSWhat is claimed is:

1. A laser diode comprising:a first section having a first electrical contact; anda second section having a second electrical contact; wherein,the first section and the second section comprise the same InAlGaN epitaxial layers; the first electrical contact overlies a first portion of the InAlGaN epitaxial layers; and the second electrical contact overlies a second portion of the InAlGaN epitaxial layers.

2. The laser diode of claim 1, wherein each of the first electrical contact and the second electrical contact comprise a metal.

3. The laser diode of claim 1, wherein the first electrical contact is electrically isolated from the second electrical contact.

4. The laser diode of any one of claims 1 and 2, comprising:a third electrical contact underlying the first portion of the InAlGaN epitaxial layers; and a fourth electrical contact underlying the second portion of the InAlGaN epitaxial layers.

5. The laser diode of claim 3, wherein each of the third electrical contact and the fourth electrical contact comprise a metal.

6. The laser diode of any one of claims 4 and 5, wherein the third electrical contact is electrically isolated from the fourth electrical contact.

7. The laser diode of any one of claims 1 to 6, wherein,the first section comprises an embedded Bragg grating;the second section comprises an embedded Bragg grating; orboth the first section and the second section comprise an embedded Bragg grating.

8. The laser diode of claim 7, wherein the embedded Bragg grating is a continuous grating.

9. The laser diode of claim 7, wherein the embedded Bragg grating is a sampled grating.Attorney Docket No.: 61ZD-000510PC-407084January 27, 2026 10. The laser diode of claim 7, wherein an uppermost epitaxial cladding layer comprises the embedded Bragg grating.

11. The laser diode of claim 10, wherein the uppermost epitaxial cladding layer is a n-InAlGaN layer.

12. The laser diode of claim 10, wherein the uppermost epitaxial cladding layer is a p-InAlGaN layer.

13. The single mode coupled cavity laser diode of claim 7, wherein the embedded Bragg grating is disposed on a p-side of the laser diode.

14. The laser diode of claim 7, wherein the embedded Bragg grating comprises alternating lateral regions of a low refractive index material and a high refractive index material.

15. The laser diode of claim 14, wherein the alternating lateral regions are disposed orthogonal to the longitudinal direction of the laser cavity.

16. The laser diode of claim 14, wherein the alternating lateral regions comprise alternating lateral regions of a transparent conductive oxide and SiCh.

17. The laser diode of claim 16, wherein the transparent conductive oxide comprises indium tin oxide.

18. The laser diode of claim 14, wherein the alternating regions comprise alternating lateral regions of low Al-content p-InAlGaN and high Al-content p-InAlGaN.

19. The laser diode of claim 14, wherein the alternating regions comprise alternating lateral regions of n-InAlGaN and SiCh.

20. The laser diode of claim 14, wherein the alternating regions comprise alternating lateral regions of low Al-content n-InAlGaN and high Al-content n-InAlGaN.

21. The laser diode of any one of claims 1 to 20, wherein the epitaxial layers comprise: an n-InAlGaN layer;an active layer overlying the n-InAlGaN layer; anda p-InAlGaN layer overlying the active layer.Attorney Docket No.: 61ZD-000510PC-407084January 27, 202622. The laser diode of any one of claims 1 to 20, wherein the epitaxial layers comprise: a first n-InAlGaN layer;an active layer overlying the n-InAlGaN layer;an p-InAlGaN layer overlying the active layer;a tunnel junction overlying the p-InAlGaN layer; anda second n-InAlGaN layer overlying the tunnel junction.

23. The laser diode of claim 22, wherein the active layer comprises InGaN.

24. The laser diode of claim 22, wherein the active layer comprises multiple quantum wells.

25. The laser diode of claim 22, comprising a transparent conductive oxide layer overlying the epitaxial layers and underlying the first electrical contact and the second electrical contact.

26. The laser diode of claim 25, wherein the transparent conductive oxide comprises indium tin oxide.

27. The laser diode of any one of claims 1 to 26, comprising a substrate underlying the InAlGaN epitaxial layers.

28. The laser diode of claim 27, wherein the substrate comprises n-GaN.

29. The laser diode of any one of claims 1 to 28 comprising:a third electrical contact underlying the first portion of the InAlGaN epitaxial layers and a first portion of the substrate; anda fourth electrical contact underlying the second portion of the InAlGaN epitaxial layers and a second portion of the substrate.

30. The laser diode of claim 29, wherein each of the third electrical contact and the fourth electrical contact comprise a metal.

31. The laser diode of any one of claims 29 to 30, wherein the third electrical contact is electrically isolated from the fourth electrical contact.Attorney Docket No.: 61ZD-000510PC-407084January 27, 2026 32. The laser diode of any one of claims 1 to 31, wherein the first section comprises a ridge waveguide master oscillator.

33. The laser diode of any one of claims 1 to 31, wherein the first section comprises a ridge waveguide master oscillator and an embedded Bragg grating.

34. The laser diode of any one of claims 1 to 33, wherein the second section comprises a ridge waveguide master oscillator.

35. The laser diode of any one of claims 1 to 33, wherein the second section comprises a ridge waveguide master oscillator and an embedded Bragg grating.

36. The laser diode of any one of claims 1 to 33, wherein the second section comprises a flared ridge waveguide power amplifier.

37. The laser diode of claim 36, wherein the flared ridge waveguide power amplifier is configured to amplify radiation emitted by the first section without altering the longitudinal and spatial mode characteristics of the radiation emitted by the first section.

38. The laser diode of any one of claims 1 to 37, wherein the single mode coupled cavity laser diode comprises a phase adjustment section, a semiconductor amplifier section, or a phase adjustment section and a semiconductor amplifier section.

39. The laser diode of any one of claims 1 to 38, comprising an airgap separating a portion of the first section and a portion of the second section.

40. The laser diode of claim 39, wherein the airgap separates the first electrical contact and the second electrical contact.

41. The laser diode of any one of claims 39 to 40, wherein the airgap does not separate the epitaxial layers of the first section and the epitaxial layers of the second section.

42. The laser diode of any one of claims 39 to 41, comprising a transparent conductive oxide layer overlying the InAlGaN epitaxial layers; wherein the airgap separates the portion of the transparent conductive oxide layer underlying the first electrical contact from the portion of the transparent conductive oxide layer underlying the second electrical contact.Attorney Docket No.: 61ZD-000510PC-407084January 27, 2026 43. The laser diode of any one of claims 39 to 42, wherein the airgap separates some of the epitaxial layers of the first section from some of the epitaxial layers of the second section.

44. The laser diode of any one of claims 39 to 42, wherein the airgap separates the epitaxial layers of the first section from the epitaxial layers of the second section.

45. The laser diode of any one of claims 39 to 42, wherein,the epitaxial layers comprise an active layer; andthe airgap separates the active layer of the first section from the active layer of the second section are separated by an airgap.

46. The laser diode of any one of claims 39 to 42, whereinthe epitaxial layers comprise an active layer and epitaxial layers overlying the active layer; andthe airgap separates the active layer and the epitaxial layers overlying the active layer of the first section from the active layer and the epitaxial layers overlying the active layer of the second section.

47. The laser diode of any one of claims 39 to 42, wherein,the epitaxial layers comprise an active layer; andthe active layer of the first section and the active layer of the second section are separated by InAlGaN.

48. The laser diode of claim 1, wherein,the first section is a first master oscillator;the second section is a power amplifier; andcomprising an airgap disposed between the first electrical contact and the second electrical contact.

49. The laser diode of claim 48, wherein the first section comprises an embedded Bragg grating.

50. The laser diode of claim 48, comprising a carrier-induced index mirror disposed between the first electrical contact and the second electrical and separated from the first electrical contact by a first airgap and from the second electrical contact by a second airgap.Attorney Docket No.: 61ZD-000510PC-407084January 27, 2026 51. The laser diode of claim 48, comprising a second active section and a semiconductor optical amplifier section, wherein an airgap is disposed between adjacent sections, wherein, each of the sections independently comprises an electrical contact; andthe electrical contacts of adjacent sections are separated by an airgap.

52. The laser diode of claim 48, wherein the airgap separates the first portion of the InAlGaN epitaxial layers and the second portion of the InAlGaN epitaxial layers.53 The laser diode of claim 48, whereinthe epitaxial layers comprise an active layer; andthe airgap separates the active layer and the epitaxial layers overlying the active layer of the first portion from the active layer and the epitaxial layers overlying the active layer of the second portion.

54. A laser diode comprising:InAlGaN epitaxial layers;a first master oscillator section comprising a first portion of the InAlGaN epitaxial layers, a first electrical contact overlying the first portion of the InAlGaN epitaxial layers, and a Bragg grating embedded within the uppermost cladding InAlGaN epitaxial layer;a phase adjustment section comprising a second portion of the InAlGaN epitaxial layers and a second electrical contact overlying the second portion of the InAlGaN epitaxial layers; anda second master oscillator section comprising a third portion of the InAlGaN epitaxial layers and a third electrical contact overlying the third portion of the InAlGaN epitaxial layers, wherein each of the electrical contacts is configured to be independently addressable and is separated from an adjacent electrical contact by an airgap.

55. A laser diode comprising:InAlGaN epitaxial layers;a master oscillator section comprising a first portion of the InAlGaN epitaxial layers, a first electrical contact and overlying the first portion of the InAlGaN epitaxial layers;an embedded Bragg grating embedded within the uppermost cladding InAlGaN epitaxial layer; anda power amplifier section comprising a second portion of the InAlGaN epitaxial layers and a second electrical contact overlying the second portion of the InAlGaN epitaxial layers, wherein each of the electrical contacts is configured to be independently addressable and is separated from an adjacent electrical contact by an airgap.Attorney Docket No.: 61ZD-000510PC-407084January 27, 2026 56. A laser diode comprising:InAlGaN epitaxial layers;a first master oscillator section comprising a first portion of the InAlGaN epitaxial layers, a first electrical contact overlying the InAlGaN epitaxial layers, and a Bragg grating embedded in the uppermost cladding InAlGaN epitaxial layer;a phase adjustment section comprising a second portion of the InAlGaN epitaxial layers and a second electrical contact overlying the second portion of the InAlGaN epitaxial layers;a second master oscillator section comprising a third portion of the InAlGaN epitaxial layers and a third electrical contact overlying the third portion of the InAlGaN epitaxial layers; anda semiconductor amplifier section comprising a fourth portion of the InAlGaN epitaxial layers and having a fourth electrical contact overlying the fourth portion of the InAlGaN epitaxial layers, wherein each of the electrical contacts is configured to be independently addressable and is separated from an adjacent electrical contact by an airgap.

57. A laser diode comprising an embedded Bragg grating.

58. The laser diode of claim 57, wherein the laser diode is configured to operate as a single mode laser.

59. The laser diode of claim 57, wherein the laser diode is configured to operate as a multimode laser.

60. The laser diode of any one of claims 57 to 59, wherein the laser diode is a ridge waveguide laser diode.

61. The laser diode of any one of claims 57 to 60, wherein the embedded Bragg grating is a continuous grating.

62. The laser diode of any one of claims 57 to 60, wherein die embedded Bragg grating is a sampled grating.

63. The laser diode of any one of claims 57 to 62, wherein the uppermost epitaxial cladding layer is an n-InAlGaN layer.

64. The laser diode of any one of claims 57 to 62, wherein the uppermost epitaxial cladding layer is a p-InAlGaN layer.Attorney Docket No.: 61ZD-000510PC-407084January 27, 2026 65. The laser diode of any one of claims 57 to 62, wherein the embedded Bragg grating is disposed on a p-side of the laser diode.

66. The laser diode of any one of claims 57 to 65, wherein the embedded Bragg grating comprises alternating lateral regions of a low refractive index material and a high refractive index material.

67. The laser diode of claim 66, wherein the alternating lateral regions are disposed orthogonal to the longitudinal direction of the laser cavity.

68. The laser diode of any one of claims 66 to 67, wherein the alternating lateral regions comprise alternating lateral regions of a transparent conductive oxide and St( K69. The laser diode of claim 68, wherein the transparent conductive oxide comprises indium tin oxide.

70. The laser diode of any one of claims 66 to 67, wherein the alternating regions comprise alternating lateral regions of low Al-content p-InAlGaN and a high Al-content p-InAlGaN.

71. The laser diode of any one of claims 66 to 67, wherein the alternating regions comprise alternating lateral regions of n-InAlGaN and SiO;.

72. The laser diode of any one of claims 66 to 67, wherein the alternating regions comprise alternating lateral regions of low Al-content n-InAlGaN and a high Al-content n-InAlGaN.

73. The laser diode of any one of claims 57 to 72, comprising epitaxial layers, wherein the Bragg grating is embedded within an uppermost epitaxial cladding layer.

74. The laser diode of any one of claims 57 to 73, comprising epitaxial layers.

75. The laser diode of claim 74, wherein the epitaxial layers comprise InAlGaN.

76. The laser diode of claim 74, wherein the epitaxial layers comprise:an n-InAlGaN layer;an active layer overlying the n-InAlGaN layer; anda p-InAlGaN layer overlying the active layer.Attorney Docket No.: 61ZD-000510PC-407084January 27, 2026 77. The laser diode of claim 74, wherein the epitaxial layers comprise:a first n-InAlGaN layer;an active layer overlying the n-InAlGaN layer;an p-InAlGaN layer overlying the active layer;a tunnel junction overlying the p-InAlGaN layer; anda second n-InAlGaN layer overlying the tunnel junction.

78. The laser diode of claim 77, wherein the active layer comprises InGaN.

79. The laser diode of any one of claims 77 to 78, wherein the active layer comprises multiple quantum wells.

80. The laser diode of any one of claims 74 to 79, comprising a transparent conductive oxide layer overlying the epitaxial layers and underlying the first electrical contact and the second electrical contact.

81. The laser diode of claim 80, wherein the transparent conductive oxide comprises indium tin oxide.

82. The laser diode of any one of claims 74 to 81, comprising a first electrical contact overlying the epitaxial layers.

83. The laser diode of any one of claims 74 to 82, comprising a second electrical contact underlying the epitaxial layers.

84. The laser diode of any one of claims 74 to 83, comprising a substrate underlying die epitaxial layers.

85. The laser diode of claim 84, wherein the substrate comprises n-GaN.

86. The laser diode of any one of claims 84 to 86, comprising an electrical contact underlying die substrate.

87. A laser diode comprising:a master oscillator section; anda power amplifier section;Attorney Docket No.: 61ZD-000510PC-407084January 27, 2026 wherein die master oscillator section and the power amplifier section are configured to be independently biased.

88. The laser diode of claim 87, wherein the master oscillator section comprises a single mode ridge waveguide laser diode.

89. The laser diode of claim 87, wherein the master oscillator section comprises a multimode ridge waveguide laser diode.

90. The laser diode of any one of claims 87 to 89, wherein the master oscillator section laser diode comprises an embedded Bragg grating.

91. The laser diode of any one of claims 87 to 90, wherein the power amplifier section comprises a tapered ridge waveguide.

92. The laser diode of any one of claims 87 to 90, whereinthe master oscillator section comprises a first electrical contact and a first portion of epitaxial layers; andthe power amplifier section comprises a second electrical contact and second portion of the epitaxial layers.

93. The laser diode of claim 92, wherein the first electrical contact and the second electrical contact are separated by an airgap.

94. The laser diode of any one of claims 92 to 93, wherein the first portion of the epitaxial layers and the second portion of epitaxial layers are separated by an airgap.

95. The laser diode of any one of claims 92 to 94, whereinthe first portion of the epitaxial layers comprise a first portion of an active layer; and the second portion of the epitaxial layers comprise a second portion of the active layer,96. The laser diode of claim 95, wherein the first portion of the active layer and the second portion of the active layer are separated by an airgap.

97. The laser diode of claim 95, wherein first portion of the active layer and the first portion of the epitaxial layers overlying the first portion of the active layer and the second first portionAttorney Docket No.: 61ZD-000510PC-407084January 27, 2026 of the active layer and the second first portion of the epitaxial layers overlying the second first portion of the active layer are separated by an airgap.

98. The laser diode of claim 95, wherein the first portion of the active layer and tire second portion of the active layer are separated by a semiconductor material.

99. The laser diode of claim 95, wherein the first portion of the active layer and the second portion of the active layer are separated by a regrown epitaxial layer.

100. The laser diode of any one of claims 87 to 99, whereinthe master oscillator section comprises a first electrical contact overlying a first portion of epitaxial layers; andthe power amplifier section comprises a second electrical contact overlying second portion of the epitaxial layers.

101. The laser diode of claim 100, wherein the first portion of the epitaxial layers and the second portion of the epitaxial layers are contiguous.

102. The laser diode of any one of claims 100 to 101, comprising a third electrical contact underlying the first portion of the epitaxial layers and the second portion of the epitaxial layers.

103. The laser diode of claim 102, wherein comprising a third electrical contact underlying the first portion of the epitaxial layers and a fourth electrical contact underlying the second portion of the epitaxial layers.

104. A multijunction edge emitting laser diode comprising:a first laser diode according to any one of claims 1 to 103; anda second laser diode according to claim 1, whereinthe second laser diode overlies the first laser diode; andthe first laser diode and the second laser diode are configured to be independently driven.

105. The multijunction edge emitting laser diode of claim 104, whereinthe epitaxial layers comprise an active layer; andthe airgap separates the active layer and epitaxial layers overlying the active layer.

106. An array of laser diodes of any one of claims 1 to 103.Attorney Docket No.: 61ZD-000510PC-407084January 27, 2026107. A semiconductor wafer comprising the laser diode of any one of claims 1 to 103, the multijunction edge emitting laser diode of any one of claims 104 to 105; or the array of laser diodes of claim 106.

108. An optoelectronic system comprising the laser diode of any one of claims 1 to 103, the multijunction edge emitting laser diode of any one of claims 104 to 105; or the array of laser diodes of claim 106.

109. The optoelectronic system of claim 108, wherein the optoelectronic system is used for quantum computing, quantum sensing, aerospace, defense, navigation and transportation, medicine and life sciences, industry and manufacturing, commercial and consumer apparatus, under underwater systems, oil and gas systems, or surveillance.

110. A laser diode comprising a first section and a second section overlying common epitaxial layers, wherein the first section comprises a master oscillator and the second section is configured to change the refractive index of one or more of the underlying epitaxial layers.

111. The laser diode of claim 110, wherein the second section is configured to render tire refractive index of one or more of the epitaxial layers such as the active layer, transparent to a lasing wavelength.

112. The laser diode of any one of claims 110 and 111, comprising a third section, wherein the third section is a second master oscillator, a power amplifier, a phase adjustment section, a mirror, a waveguide, or other optoelectronic component.

113. The laser diode of any one of claims 110 and 112, wherein the first section comprises an embedded Bragg grating.

114. The laser diode of any one of claims 110 and 113, wherein the first section and the second section are configured to be independently biased.

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