Heterojunction integrated ultra-wideband tunable semiconductor laser

Abstract

The invention provides a heterojunction integrated ultra-wideband tunable semiconductor laser, which comprises an III-V / Si heterojunction gain module, a DBR-micro-ring composite tuning module, a phase control module, a bus waveguide, an adjustable coupler module and an output module which are integrated on a CMOS compatible silicon photon chip, and all the modules act synergistically, so that high-efficiency excitation of wide-spectrum gain is ensured, and high-efficiency excitation of the wide-spectrum gain is realized. And accurate wavelength tuning and stable laser output are realized, and core light source support is provided for the fields of ultra-wideband optical communication, high-precision optical sensing and the like. According to the invention, ultra-wideband wavelength tuning (covering an S band, a C band and an L band) can be realized, the integration level is high, the power consumption is low, the stability is high, and the method is suitable for the fields of ultra-wideband wavelength division multiplexing transmission, frequency modulation continuous wave laser radar, distributed optical fiber sensing, medical wearable equipment and the like.

Description

Technical Field

[0001] This invention relates to the field of semiconductor lasers and integrated photonics technology, specifically a heterojunction integrated ultrawideband tunable semiconductor laser. Background Technology

[0002] High-performance tunable semiconductor lasers are the core light source for modern optical communication, optical sensing, and radio frequency photonics systems. Their tuning range, integration, and stability directly determine the system performance. With the development of technologies such as artificial intelligence and cloud computing, applications such as ultra-wideband wavelength division multiplexing (WDM) communication and long-distance FMCWLiDAR are placing higher demands on the tuning range of lasers, requiring coverage of multiple communication bands such as S, C, and L, or achieving ultra-wideband tuning at the level of hundreds of nanometers.

[0003] Traditional tunable lasers face several technical bottlenecks: First, lasers based on a single tuning mechanism (such as dual micro-ring vernier tuning or single distributed Bragg reflection (DBR) tuning) typically have a tuning range limited to a single band (e.g., only covering the C-band), making it difficult to meet the needs of ultra-wideband applications. Second, while silicon photonics technology has the advantages of high integration and CMOS compatibility, silicon is an indirect bandgap material and cannot achieve efficient light emission. It requires the introduction of III-V group gain materials through heterogeneous integration. However, existing heterogeneous integration schemes (such as flip-chip bonding and dual micro-ring tuning) suffer from high coupling loss and poor tuning stability, and are difficult to work in conjunction with silicon-based passive devices (such as DBR gratings). Third, existing lasers mostly use discrete tuning and gain modules, resulting in low integration, high system power consumption, and large size, making them unsuitable for miniaturized, low-power applications (such as wearable sensing).

[0004] Furthermore, existing heterojunction integrated lasers suffer from limited material compatibility, mostly confined to the III-V / Si binary system, making it difficult to combine the advantages of low-loss, high-stability materials such as silicon nitride (Si3N4) and thin-film lithium niobate (LN). Simultaneously, mode switching and linewidth degradation are prone to occur during tuning, affecting the stability and coherence of the laser signal. Therefore, developing a heterojunction integrated laser that combines ultra-wideband tuning, high integration, multi-material compatibility, and high stability is crucial to overcoming current technological bottlenecks. Summary of the Invention

[0005] The purpose of this invention is to provide a heterojunction integrated ultrawideband tunable semiconductor laser to solve the technical problems of traditional tunable lasers, such as narrow tuning range, low integration, high power consumption and poor stability.

[0006] The present invention is implemented as follows: a heterojunction integrated ultrawideband tunable semiconductor laser, comprising a III-V / Si heterojunction gain module, a DBR-microring composite tuning module, a phase control module, a bus waveguide, a tunable coupler module, and an output module integrated on a photonic chip; III-V / Si heterojunction gain module, used to provide optical gain and generate optical signals; The DBR-microring composite tuning module includes a grating unit DBR, a first microring resonator R1, a second microring resonator R2, and a third microring resonator R3. The optical input terminal of the grating unit DBR is connected to the optical output terminal of the gain module via a bus waveguide, and is used to select the wavelength of the optical signal and form a partial reflection output. The first microring resonator R1, the second microring resonator R2, and the third microring resonator R3 are connected in a cascaded or ring-connected manner via a bus waveguide. The input terminal of the first microring resonator R1 is optically connected to the output terminal of the grating unit DBR. The bus waveguide has its input end optically connected to the output end of the heterojunction gain module, and is sequentially connected to the grating unit DBR, the first microring resonator R1, the second microring resonator R2, and the third microring resonator R3. After circling half a cycle around the outer edge of the chip, it is coupled to the grating unit DBR. Together with the gain module, the grating unit DBR, the first microring resonator R1, the second microring resonator R2, and the third microring resonator R3, it forms a resonant cavity. Finally, it is optically connected to the adjustable coupler module. The phase control module is used to adjust the phase of the laser cavity mode to ensure cavity mode stability during tuning. The adjustable coupler module, with its input end connected to the bus waveguide optics and its output end connected to the laser output module, is used to dynamically adjust the coupling ratio across the entire wavelength tuning range, switching between "reflection priority" and "output priority" operating modes; and The laser output module is used to output the tuned laser signal, and its optical input end is optically connected to the output end of the ring resonant cavity.

[0007] Furthermore, the present invention can be implemented according to the following technical solution: The phase control module includes microheaters integrated into the corresponding waveguide regions of the grating unit DBR, the first microring resonator R1, the second microring resonator R2, the third microring resonator R3, and the bus waveguide, respectively, for independently controlling the effective refractive index of each unit.

[0008] The III-V / Si heterojunction gain module combines III-V group semiconductor gain materials with silicon waveguides through heterojunction technology to form a wide-band optical gain region. The heterojunction gain module employs a heterogeneous integration technology selected from at least one of wafer bonding, micro-transfer printing, direct molecular bonding, or intermediate layer bonding; the III-V semiconductor gain material is an epitaxial layer containing InAlGaAs, InGaAsP, or GaAs-based multiple quantum well (MQW); and the silicon waveguide is a strip or rib structure.

[0009] The grating unit DBR includes at least one quarter-wavelength phase shift segment to achieve single-mode selection, and is made of silicon, silicon nitride (Si3N4), or thin-film lithium niobate (LN) material; the first microring resonator R1, the second microring resonator R2, and the third microring resonator R3 have different perimeters and are made of ultra-low loss waveguides, with waveguide materials selected from silicon, Si3N4, or LN.

[0010] The adjustable coupler module is a thermo-optical directional coupler or an electro-optical directional coupler. In the "reflection priority" mode, the optical signal is reflected back to the gain module to maintain laser oscillation. In the "output priority" mode, the coupling ratio can be adjusted to guide part of the optical signal to the output module, and the coupling ratio of the coupler is optimized by feedback from the monitoring signal of the output module.

[0011] The output module includes a main output terminal and a backup output terminal; the main output terminal is a polished silicon waveguide end face or an inverse tapered waveguide, which is compatible with standard single-mode fiber or high numerical aperture fiber; a miniature monitoring photodiode is integrated at the front end of the backup output terminal to collect the output power signal in real time and feed the signal back to the phase control module and the adjustable coupler module to dynamically adjust the cavity mode phase and coupling ratio.

[0012] It also includes a semiconductor optical amplifier (SOA) submodule, which is integrated between the III-V / Si heterojunction gain module and the DBR-micro-ring composite tuning module, or integrated at the front end of the output module, to compensate for losses during optical transmission and improve output power stability.

[0013] The CMOS-compatible silicon photonic chip also integrates silicon-based passive devices, which are selected from at least one of arrayed waveguide gratings (AWG), optical couplers, waveguide filters, or polarization controllers, and are used to realize the multiplexing, demultiplexing, or polarization optimization of optical signals.

[0014] The tuning range of the DBR-micro-ring composite tuning module covers at least two of the following bands: S-band 1460~1530nm, C-band 1530~1565nm, and L-band 1565~1625nm. The side-mode rejection ratio (SMSR) is not less than 40dB, and the relative intensity noise (RIN) is not higher than -150dBc / Hz.

[0015] The heterojunction integrated ultrawideband tunable semiconductor laser is applied to ultrawideband wavelength division multiplexing communication systems, frequency modulated continuous wave lidar systems, distributed fiber optic sensing systems, or medical wearable sensing systems, and realizes multi-channel communication, long-distance ranging, or high-precision sensing through ultrawideband tuning characteristics.

[0016] This invention proposes a technical solution of "DBR-microring composite tuning + multi-material heterogeneous integration," which combines the narrowband high selectivity of distributed Bragg reflection (DBR) with the wide tuning capability of multi-microring resonators using the vernier effect, supplemented by a III-V / Si heterojunction gain module and a CMOS-compatible integrated design, to achieve ultra-wideband, high-stability, and highly integrated laser output. Specifically, the heterojunction integrated ultra-wideband tunable semiconductor laser of this invention includes a III-V / Si heterojunction gain module, a DBR-microring composite tuning module, a phase control module, a tunable coupler module, and an output module. All modules are integrated on the same CMOS-compatible silicon photonic chip. The modules work together to ensure efficient excitation of the wideband gain and achieve precise wavelength tuning and stable laser output, providing core light source support for ultra-wideband optical communication, high-precision optical sensing, and other fields. This invention enables ultra-wideband wavelength tuning (covering S-band, C-band and L-band), and features high integration, low power consumption and high stability. It is suitable for ultra-wideband wavelength division multiplexing transmission, frequency-modulated continuous wave lidar, distributed fiber optic sensing and medical wearable devices.

[0017] Compared with existing technologies, the present invention has significant advantages: 1. Outstanding ultra-wideband tuning capability: Through the coordinated tuning of the grating unit DBR and the multi-micro-ring resonator, combined with the broadband gain characteristics of III-V group materials, ultra-wideband tuning covering multiple bands of S, C, and L can be achieved, breaking through the limitations of the tuning range of traditional lasers. 2. Significant advantages in high integration and low cost: All modules are integrated into CMOS-compatible silicon photonic chips, compatible with existing semiconductor manufacturing processes, enabling wafer-level mass production, which reduces manufacturing costs and significantly reduces device size, making it suitable for miniaturized application scenarios. 3. Strong compatibility with multiple materials, supporting heterogeneous integration of various materials such as III-V group, Si, Si3N4, LN, etc., and can select low-loss (such as Si3N4) or high electro-optic effect (such as LN) materials according to application requirements, flexibly optimizing device performance. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the present invention.

[0019] Figure 2 This is a schematic diagram of the DBR-microring composite tuning module system of the present invention.

[0020] Figure 3 This is a diagram of the heterogeneous integrated stacked structure of the present invention.

[0021] Figure 4 This is a schematic diagram of the superimposed lasing spectrum of the present invention.

[0022] Figure 5 This is a graph showing the optical power-current (LI) curve of the present invention. Detailed Implementation

[0023] like Figure 1 As shown, the present invention discloses a heterojunction integrated ultrawideband tunable semiconductor laser, comprising a III-V / Si heterojunction gain module, a DBR-microring composite tuning module, a phase control module, a bus waveguide, a tunable coupler module, and an output module integrated on a CMOS-compatible silicon photonic chip.

[0024] The core function of this invention is to demonstrate the end-to-end integrated logic of "gain excitation - wavelength tuning - cavity mode stabilization - signal output". The left-side III-V / Si heterojunction gain module is a broadband optical signal source. It generates optical gain covering the S, C, and L bands by exciting a III-V group multiple quantum well (MQW) through carrier injection. The optical signal is transmitted with low loss to the intermediate tuning unit via an internal tapered transition region (located between the gain module and the tuning module). The intermediate DBR-microring composite tuning module is the core of ultra-wideband tuning. It first filters the fundamental wavelength and suppresses non-target modes through a DBR grating unit, and then expands the tuning range through the vernier effect of the multi-microring resonator unit, outputting a single target wavelength optical signal. The phase control module adjacent to the tuning module compensates for cavity mode phase shift in real time: it adjusts the effective refractive index of the waveguide through thermo-optic / electro-optic effects to offset mode drift caused by temperature fluctuations or tuning, ensuring laser mode stability. The adjustable coupler module switches between "oscillation maintenance" and "signal output": in "reflection priority" mode, the optical signal is reflected back to the gain module to maintain laser oscillation. In "output priority" mode, some optical signals are reflected to maintain oscillation, while the rest are directed to the output module. The right-side output module completes signal extraction and monitoring: the main output terminal is adapted to optical fiber output via an inverse tapered waveguide; the alternative output terminal integrates a monitoring photodiode to collect power signals in real time and feed them back to the phase control and coupler module for dynamic parameter optimization. All modules are integrated on a CMOS-compatible silicon photonic chip substrate, adapting to wafer-level mass production processes to ensure high integration and low cost.

[0025] The III-V / Si heterojunction gain module is used to provide optical gain and generate optical signals. It combines III-V group semiconductor gain materials with silicon waveguides through heterogeneous integration technology to form a wide-band optical gain region. The specific heterogeneous integration technology used is selected from at least one of wafer bonding, micro-transfer printing, direct molecular bonding, or intermediate layer bonding. As the gain source for laser output, the III-V / Si heterojunction gain module uses III-V group multiple quantum wells (such as InAlGaAsMQW and InGaAsPMQW) as the core gain medium. It achieves heterogeneous integration with the silicon waveguide through wafer bonding (including direct molecular bonding, BCB intermediate layer bonding, etc.) or micro-transfer printing technology, ensuring efficient integration of the gain medium and the transmission structure. The III-V semiconductor gain material is an epitaxial layer containing InAlGaAs, InGaAsP, or GaAs-based multiple quantum wells (MQWs), and the silicon waveguide is a strip or rib structure. By optimizing the waveguide size and morphology, the distribution ratio of the optical field in the III-V material and the silicon waveguide is adjusted to balance the gain extraction efficiency and transmission loss. At the same time, a tapered waveguide structure is used in the transition region between the III-V material and the silicon waveguide to further reduce the coupling loss during mode conversion, laying the foundation for the effective transmission of broadband gain.

[0026] The DBR-microring composite tuning module includes a grating unit DBR, a first microring resonator R1, a second microring resonator R2, and a third microring resonator R3. The tuning range of the DBR-microring composite tuning module covers at least two of the following bands: S-band (1460~1530nm), C-band (1530~1565nm), and L-band (1565~1625nm), with a side-mode rejection ratio (SMSR) of not less than 40dB and a relative intensity noise (RIN) of not more than -150dBc / Hz.

[0027] The optical input terminal of the grating unit DBR is connected to the optical output terminal of the gain module through a bus waveguide, which is used to select the wavelength of the optical signal and form a partial reflection output, providing basic wavelength selection. The micro-ring resonator unit expands the tuning range through the vernier effect. The two work together to achieve ultra-wideband wavelength tuning.

[0028] The grating unit DBR is a distributed Bragg reflector (DBR) grating unit containing at least one quarter-wavelength phase shift segment to achieve single-mode selection. It is made of silicon, silicon nitride (Si3N4), or thin-film lithium niobate (LN) materials. Its grating period and duty cycle are customized according to the target operating band (S / C / L band), which can effectively suppress multimode oscillation and ensure single-mode output. The reflection spectrum of this grating unit DBR covers the basic range of the target tuning band, which can perform preliminary wavelength screening of the gain optical signal and filter out invalid signals outside the target band.

[0029] The first microring resonator R1, the second microring resonator R2, and the third microring resonator R3 are connected by cascaded bus waveguides or ring interconnection. The input terminal of the first microring resonator R1 is optically connected to the output terminal of the grating unit DBR. The first microring resonator R1, the second microring resonator R2, and the third microring resonator R3 have different perimeters and are fabricated using ultra-low loss waveguides made of silicon, Si3N4, or LN. The difference in perimeter of each microring creates a vernier effect, and the microrings are connected by cascaded bus waveguides or ring interconnection. Utilizing the vernier effect of multiple microrings, the resonance peaks of each microring superimpose to form a wide-range tuning window, significantly expanding the tuning range of the grating unit DBR. Simultaneously, it deeply suppresses sidelobe modes in the reflection spectrum, further improving the side-mode suppression ratio of the laser and ensuring mode stability during tuning.

[0030] The bus waveguide has its input end optically connected to the output end of the heterojunction gain module, and is sequentially connected to the grating unit DBR, the first microring resonator R1, the second microring resonator R2, and the third microring resonator R3. After circling half a cycle around the outer edge of the chip, it is coupled to the grating unit DBR. Together with the gain module, the grating unit DBR, the first microring resonator R1, the second microring resonator R2, and the third microring resonator R3, it forms a resonant cavity, and finally connects to the optical path of the laser output module.

[0031] The phase control module is used to regulate the phase of the laser cavity mode, ensuring cavity mode stability during tuning. The phase control module is a metal heater deposited next to the silicon waveguide or microring resonator. Specifically, it includes microheaters integrated into the corresponding waveguide regions of the grating unit DBR, the first microring resonator R1, the second microring resonator R2, the third microring resonator R3, and the bus waveguide, respectively, for independently controlling the effective refractive index of each unit. The microheaters are positioned above the semicircular portions of the first microring resonator R1, the second microring resonator R2, and the third microring resonator R3, along the extended portion of the bus waveguide along the chip's closed path, and between the bus waveguide and the grating unit DBR.

[0032] The phase control module can regulate the effective refractive index of the waveguide through thermo-optic effects or be an electro-optic phase tuning unit based on carrier injection. The module's control range covers the compensation requirements for temperature fluctuations and cavity mode phase shifts during tuning. The phase control module is used to compensate for temperature fluctuations and cavity mode phase shifts generated during tuning. A thermo-optic control scheme is preferred, where a metal heater is deposited in the waveguide region next to the micro-ring resonator or grating unit DBR. Adjusting the heater power changes the local temperature of the waveguide, thereby regulating the effective refractive index and achieving precise cavity mode phase compensation. For applications requiring rapid tuning (such as high-speed optical communication and dynamic sensing), this module can be replaced with an electro-optic phase tuning unit based on carrier injection / depletion, directly regulating the waveguide refractive index through electrical signals, significantly improving phase tuning speed and meeting the performance requirements of different scenarios.

[0033] The input of the adjustable coupler module is optically connected to the bus waveguide, and the output is connected to the laser output module. It is used to dynamically adjust the coupling ratio across the entire wavelength tuning range and switch between "reflection priority" and "output priority" operating modes. The adjustable coupler module is either a thermo-optically controlled directional coupler or an electro-optically controlled directional coupler, and has the ability to switch between "reflection priority" and "output priority" operating modes.

[0034] In "reflection priority" mode, the optical signal can be reflected back to the III-V / Si heterojunction gain module to maintain stable laser oscillation. In "output priority" mode, the coupling ratio can be dynamically adjusted, guiding part of the optical signal to the output module while retaining part of the signal for cavity mode stabilization. The coupling ratio of the coupler is optimized through feedback from the monitoring signal of the output module. By receiving the monitoring feedback signal from the output module, this module can optimize the coupling ratio in real time, maximizing output power while ensuring laser oscillation stability, thus achieving a performance balance.

[0035] The laser output module outputs the tuned laser signal, with its optical input end optically connected to the output end of the ring resonator. The output module performs laser signal extraction and real-time monitoring, comprising a main output end and a backup output end. The main output end employs a polished silicon waveguide endface or an inverse tapered waveguide structure. The polished silicon waveguide endface is compatible with standard single-mode fiber, while the inverse tapered waveguide is compatible with high numerical aperture fiber. Both designs effectively reduce fiber coupling loss and meet the connection requirements of different application scenarios. The backup output end integrates a miniature monitoring photodiode at its front end for real-time acquisition of the output power signal. This signal is fed back to the phase control module and the adjustable coupler module to dynamically adjust the cavity mode phase and coupling ratio, ensuring long-term stability of the laser output power and preventing performance degradation due to environmental fluctuations.

[0036] The present invention also includes a semiconductor optical amplifier (SOA) submodule, which is integrated between the III-V / Si heterojunction gain module and the DBR-micro-ring composite tuning module, or integrated at the front end of the output module, to compensate for losses during optical transmission and improve output power stability.

[0037] The CMOS-compatible silicon photonic chip also integrates silicon-based passive devices, which are selected from at least one of arrayed waveguide gratings (AWG), optical couplers, waveguide filters, or polarization controllers, and are used to realize the multiplexing, demultiplexing, or polarization optimization of optical signals.

[0038] This invention can be used in ultra-wideband wavelength division multiplexing (WDM) communication systems, frequency modulated continuous wave (FMCW) lidar systems, distributed fiber optic sensing systems, or medical wearable sensing systems to achieve multi-channel communication, long-distance ranging, or high-precision sensing through ultra-wideband tuning characteristics.

[0039] The workflow of this invention is as follows: First, a pump current is injected into the III-V / Si heterojunction gain module, and the III-V group multi-quantum well is stimulated to generate a broadband optical gain covering multiple bands such as S, C, and L. Then, the gain optical signal enters the DBR-microring composite tuning module. The grating unit DBR first performs preliminary screening of the signal, retaining the optical signal within the target band and filtering out invalid modes outside the target band. Next, the multi-microring resonator expands the tuning range through the vernier effect, realizing ultra-wideband wavelength selection and suppressing sidelobe modes, further optimizing the signal quality. During this process, the phase control module adjusts the effective refractive index of the waveguide / microring in real time according to the feedback signal of the monitoring photodiode, compensates for cavity mode phase shift, and ensures laser mode stability. Finally, the adjustable coupler module switches to the "output priority" mode, adjusts the coupling ratio according to the requirements, and guides the optimized laser signal to the output module. The monitoring photodiode continuously collects power signals and feeds them back, dynamically adjusting the parameters of each module to maintain stable laser output.

[0040] like Figure 2As shown in the figure, the internal structure details of the DBR-micro-ring composite tuning module provided by the present invention are illustrated, which mainly explains the synergistic mechanism of "DBR grating narrowband selection + multi-micro-ring vernier effect wide tuning": the grating unit DBR on the left adopts a periodic structure and contains a quarter-wavelength phase shift segment. Through the periodic change of the grating refractive index, it generates strong reflection of specific wavelength light signals and suppresses non-target wavelengths, thereby achieving the basic wavelength selection of "narrowband high selectivity". The multi-microring resonator unit on the right contains three cascaded microrings (first microring resonator R1, second microring resonator R2, and third microring resonator R3). The perimeters of each microring differ. Utilizing the "vernier effect," when the resonant peaks of each microring are superimposed, only the target wavelength resonant peak overlaps to form an effective transmission channel, while the non-target wavelength resonant peaks cancel each other out. This expands the tuning range of the DBR grating unit from a single band to multiple bands (S+C+L). Simultaneously, the sidelobe suppression ratio is improved by synergistically suppressing sidelobe modes through multi-microrings. The input bus waveguide uniformly guides the optical signal filtered by the DBR grating into the multi-microring unit, while the output bus waveguide transmits the tuned single-wavelength signal to the phase control module. The simplified reflection spectrum supplemented below the attached figure visually demonstrates the expansion effect of the tuning range from "DBR narrowband" to "multi-microring broadband." The horizontal axis represents wavelength, and the vertical axis represents reflection intensity, labeled "DBR main reflection peak" and "microring vernier extended peak."

[0041] like Figure 3 The diagram shows a stacked structure of the laser of this invention, illustrating the interlayer interaction mechanism of "multi-material heterogeneous integration": The bottom silicon substrate layer uses high thermal conductivity single-crystal silicon material, serving as the mechanical support substrate for the entire laser and rapidly conducting the heat generated during the operation of each module, preventing local overheating and performance degradation; the buried oxide layer above the silicon substrate uses SiO2 material, serving as an insulating layer to isolate the silicon substrate from the upper silicon waveguide, preventing electrical signal interference and defining the mode constraint range of the silicon waveguide; the silicon waveguide layer above the buried oxide layer uses a strip or ribbed silicon structure, serving as the main transmission channel for optical signals, confining the optical signals within the waveguide for low-loss transmission through mode constraints, and simultaneously providing an integration substrate for the upper III-V material; the II layer above the silicon waveguide layer... The I-V multi-quantum-well layer is combined with the silicon waveguide through heterogeneous integration technology (such as direct bonding and BCB intermediate layer bonding) to serve as an optical gain region. When charge carriers are injected, electrons in the multi-quantum-well transition to generate photons, and some photons couple into the silicon waveguide to form an optical signal. The metal heater layer on the side of the III-V layer and above the silicon waveguide layer adopts a Ti / Pt / Au metal stack and serves as the core execution unit of the phase control module. It generates heat by applying current and uses the thermo-optic effect to change the effective refractive index of the silicon waveguide, thereby adjusting the phase of the optical signal to compensate for the cavity mode shift. The top passivation layer adopts SiO2 or Si3N4 material to protect the lower structure from the influence of the external environment (such as humidity and impurities) and to prevent electrical short circuits between the metal heater and other modules.

[0042] Figure 4 This is a schematic diagram of the laser of the present invention within the ultra-wideband tuning range, clearly demonstrating the continuous wavelength tuning capability achieved through the DBR-microring composite tuning module. The spectrum covers the S-band (1460-1530nm), C-band (1530-1565nm), and L-band (1565-1625nm). At each wavelength, the spectral peaks are distinct, the linewidth is narrow, and the side-mode suppression ratio is high (≥40dB). This verifies the effectiveness of the synergistic operation of the narrowband selectivity of the DBR unit and the multi-microring vernier effect, enabling both wide-range tuning and ensuring the purity and stability of single-mode laser output. Figure 5 The optical power-current (LI) characteristic curve of this invention shows that the laser has a low threshold current and good linear output characteristics at different tuning wavelengths, and the optical power can reach more than 20mW. This indicates that the III-V / Si heterojunction gain module provides efficient broadband gain, while the synergistic effect of the phase control module and the tunable coupler module ensures power stability across the entire wavelength range, meeting the requirements of practical applications for light source efficiency and reliability.

Claims

1. A heterojunction integrated ultrawideband tunable semiconductor laser, characterized in that, This includes a III-V / Si heterojunction gain module, a DBR-micro-ring composite tuning module, a phase control module, a bus waveguide, a tunable coupler module, and an output module integrated on a photonic chip; III-V / Si heterojunction gain module, used to provide optical gain and generate optical signals; The DBR-microring composite tuning module includes a grating unit DBR, a first microring resonator R1, a second microring resonator R2, and a third microring resonator R3. The optical input terminal of the grating unit DBR is connected to the optical output terminal of the gain module via a bus waveguide, and is used to select the wavelength of the optical signal and form a partial reflection output. The first microring resonator R1, the second microring resonator R2, and the third microring resonator R3 are connected in a cascaded or ring-connected manner via a bus waveguide. The input terminal of the first microring resonator R1 is optically connected to the output terminal of the grating unit DBR. The bus waveguide has its input end optically connected to the output end of the heterojunction gain module, and is sequentially connected to the grating unit DBR, the first microring resonator R1, the second microring resonator R2, and the third microring resonator R3. After circling half a cycle around the outer edge of the chip, it is coupled to the grating unit DBR. Together with the gain module, the grating unit DBR, the first microring resonator R1, the second microring resonator R2, and the third microring resonator R3, it forms a resonant cavity. Finally, it is optically connected to the adjustable coupler module. The phase control module is used to adjust the phase of the laser cavity mode to ensure cavity mode stability during tuning. The adjustable coupler module, with its input end connected to the bus waveguide optics and its output end connected to the laser output module, is used to dynamically adjust the coupling ratio across the entire wavelength tuning range, switching between "reflection priority" and "output priority" operating modes; and The laser output module is used to output the tuned laser signal, and its optical input end is optically connected to the output end of the ring resonant cavity.

2. The heterojunction integrated ultrawideband tunable semiconductor laser according to claim 1, characterized in that, The phase control module includes microheaters integrated into the corresponding waveguide regions of the grating unit DBR, the first microring resonator R1, the second microring resonator R2, the third microring resonator R3, and the bus waveguide, respectively, for independently controlling the effective refractive index of each unit.

3. A heterojunction integrated ultrawideband tunable semiconductor laser according to claim 1, characterized in that, The III-V / Si heterojunction gain module combines III-V group semiconductor gain materials with silicon waveguides through heterojunction technology to form a wide-band optical gain region. The heterojunction gain module employs a heterogeneous integration technology selected from at least one of wafer bonding, micro-transfer printing, direct molecular bonding, or intermediate layer bonding; the III-V semiconductor gain material is an epitaxial layer containing InAlGaAs, InGaAsP, or GaAs-based multiple quantum well (MQW); and the silicon waveguide is a strip or rib structure.

4. A heterojunction integrated ultrawideband tunable semiconductor laser according to claim 1, characterized in that, The grating unit DBR includes at least one quarter-wavelength phase shift segment to achieve single-mode selection, and is made of silicon, silicon nitride (Si3N4), or thin-film lithium niobate (LN) material; the first microring resonator R1, the second microring resonator R2, and the third microring resonator R3 have different perimeters and are made of ultra-low loss waveguides, with waveguide materials selected from silicon, Si3N4, or LN.

5. A heterojunction integrated ultrawideband tunable semiconductor laser according to claim 1, characterized in that, The adjustable coupler module is a thermo-optical directional coupler or an electro-optical directional coupler. In the "reflection priority" mode, the optical signal is reflected back to the gain module to maintain laser oscillation. In the "output priority" mode, the coupling ratio can be adjusted to guide part of the optical signal to the output module, and the coupling ratio of the coupler is optimized by feedback from the monitoring signal of the output module.

6. A heterojunction integrated ultrawideband tunable semiconductor laser according to claim 1, characterized in that, The output module includes a main output terminal and a backup output terminal; the main output terminal is a polished silicon waveguide end face or an inverse tapered waveguide, which is compatible with standard single-mode fiber or high numerical aperture fiber; a miniature monitoring photodiode is integrated at the front end of the backup output terminal to collect the output power signal in real time and feed the signal back to the phase control module and the adjustable coupler module to dynamically adjust the cavity mode phase and coupling ratio.

7. A heterojunction integrated ultrawideband tunable semiconductor laser according to claim 1, characterized in that, It also includes a semiconductor optical amplifier (SOA) submodule, which is integrated between the III-V / Si heterojunction gain module and the DBR-micro-ring composite tuning module, or integrated at the front end of the output module, to compensate for losses during optical transmission and improve output power stability.

8. A heterojunction integrated ultrawideband tunable semiconductor laser according to claim 1, characterized in that, The CMOS-compatible silicon photonic chip also integrates silicon-based passive devices, which are selected from at least one of arrayed waveguide gratings (AWG), optical couplers, waveguide filters, or polarization controllers, and are used to realize the multiplexing, demultiplexing, or polarization optimization of optical signals.

9. A heterojunction integrated ultrawideband tunable semiconductor laser according to claim 1, characterized in that, The tuning range of the DBR-micro-ring composite tuning module covers at least two of the following bands: S-band 1460~1530nm, C-band 1530~1565nm, and L-band 1565~1625nm. The side-mode rejection ratio (SMSR) is not less than 40dB, and the relative intensity noise (RIN) is not higher than -150dBc / Hz.

10. A heterojunction integrated ultrawideband tunable semiconductor laser according to claim 1, characterized in that, The heterojunction integrated ultrawideband tunable semiconductor laser is applied to ultrawideband wavelength division multiplexing communication systems, frequency modulated continuous wave lidar systems, distributed fiber optic sensing systems, or medical wearable sensing systems, and realizes multi-channel communication, long-distance ranging, or high-precision sensing through ultrawideband tuning characteristics.

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