Optical device

Abstract

An optical apparatus is disclosed. Systems and methods for an ultrafast modulated vertical cavity surface emitting laser (VCSEL) are provided. An exemplary optical device includes a light source and an electro-absorption modulated laser (EML)-based structure on top of the light source. An electro-absorption modulated laser (EML)-based structure includes a grating structure that includes a plurality of grating lines, and the grating structure further includes a Pockels material disposed within the grating structure.

Description

[0001] Priority declaration

[0002] This patent application claims priority to and the benefit of U.S. Provisional Patent Application Serial No. 63 / 532,778, filed on August 15, 2023, and U.S. Provisional Patent Application Serial No. 63 / 575,281, filed on April 5, 2024. Each of the above applications is incorporated herein by reference in its entirety. Technical Field

[0003] Various aspects of the present disclosure relate to solutions based on optical communications. More specifically, certain implementations of the present disclosure relate to methods and systems for implementing and utilizing ultrafast modulated vertical cavity surface emitting lasers (VCSELs). Background Art

[0004] The limitations and disadvantages of such systems will become apparent to those skilled in the art by comparing conventional diffraction gratings with certain aspects of the present disclosure as set forth in the remainder of this application with reference to the figures. Summary of the invention

[0005] Systems and methods are provided for ultrafast modulation of a vertical cavity surface emitting laser (VCSEL) substantially as shown and / or described in conjunction with at least one of the figures, as more fully set forth in the claims.

[0006] These and other advantages, aspects and novel features of the present disclosure and details of illustrated embodiments thereof will be more fully understood from the following description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1A to Figure 1B An exemplary ultrafast modulated vertical cavity surface emitting laser (VCSEL) incorporating a Pockels material within an interdigitated grating to enhance performance is shown in accordance with the present disclosure.

[0008] Figure 2 An exemplary vertical cavity surface emitting laser (VCSEL) is shown.

[0009] Figure 3 An exemplary photonic crystal surface emitting laser (PCSEL) is shown.

[0010] Figure 4 An exemplary high-order distributed feedback polymer (DFB) is shown.

[0011] Figure 5A An exemplary vertical cavity surface emitting laser (VCSEL) based electro-absorption modulated laser (EML) according to the present disclosure is shown.

[0012] Figure 5BAn exemplary 3-contact vertical cavity surface emitting laser (VCSEL) based electro-absorption modulated laser (EML) according to the present disclosure is shown.

[0013] Figure 5C An exemplary 4-contact vertical cavity surface emitting laser (VCSEL) based electro-absorption modulated laser (EML) according to the present disclosure is shown.

[0014] Figure 6 An exemplary high contrast grating (HCG) structure according to the present disclosure is shown.

[0015] Figure 7 The use of an exemplary high contrast grating (HCG) structure as a reflectivity modulator in accordance with the present disclosure is shown.

[0016] Figure 8 The use of an exemplary high contrast grating (HCG) structure in wavefront modulation according to the present disclosure is shown.

[0017] Fig. 9 The use of an exemplary vertical cavity surface emitting laser (VCSEL) based electro-absorption modulated laser (EML) incorporating a high contrast grating (HCG) with a Pockels material as an intensity modulator in accordance with the present disclosure is shown.

[0018] Fig.10 Different processes for fabricating a vertical cavity surface emitting laser (VCSEL) based electro-absorption modulated laser (EML) incorporating a high contrast grating (HCG) with a Pockels material according to the present disclosure are shown.

[0019] Fig.11 Dephasing in an exemplary vertical cavity surface emitting laser (VCSEL) based electro-absorption modulated laser (EML) incorporating a high contrast grating (HCG) with a Pockels material according to the present disclosure is shown.

[0020] Fig.12 The use of an exemplary vertical cavity surface emitting laser (VCSEL) based electro-absorption modulated laser (EML) in wavefront modulation in accordance with the present disclosure, the VCSEL based EML incorporating a high contrast grating (HCG) with a Pockels material, is shown.

[0021] Fig.13 An exemplary use of a vertical cavity surface emitting laser (VCSEL) based electro-absorption modulated laser (EML) in wavefront modulation in accordance with the present disclosure is shown, wherein the VCSEL based EML incorporates a high contrast grating (HCG) with a Pockels material on top of the contacts.

[0022] Fig.14 The processing of an exemplary vertical cavity surface emitting laser (VCSEL) based electro-absorption modulated laser (EML) having a high contrast grating (HCG) incorporating a Pockels material according to the present disclosure is shown.

[0023] Fig.15 The use of an exemplary vertical cavity surface emitting laser (VCSEL) based electro-absorption modulated laser (EML) in polarization modulation in accordance with the present disclosure, the VCSEL based EML incorporating a high contrast grating (HCG) with a Pockels material, is shown.

[0024] Fig.16 An exemplary variation of a high contrast grating (HCG) structure with a Pockels material according to the present disclosure is shown.

[0025] Fig.17 A first exemplary implementation of an interdigital electro-absorption modulated laser (EML) based structure according to the present disclosure is shown.

[0026] Fig.18 A second exemplary implementation of an interdigital electro-absorption modulated laser (EML) based structure according to the present disclosure is shown.

[0027] Fig.19 A third exemplary implementation of an interdigital electro-absorption modulated laser (EML) based structure according to the present disclosure is shown.

[0028] Fig. 20 A fourth exemplary implementation and a fifth exemplary implementation of an interdigital electro-absorption modulated laser (EML) based structure according to the present disclosure are shown.

[0029] Fig.21 A sixth exemplary implementation of an interdigital electro-absorption modulated laser (EML) based structure according to the present disclosure is shown.

[0030] Fig. 22 An exemplary vertical cavity surface emitting laser (VCSEL) based electro-absorption modulated laser (EML) incorporating a high contrast grating (HCG) having a Pockels material and a dielectric for a gate according to the present disclosure is shown.

[0031] Fig.23 Exemplary vertical cavity surface emitting laser (VCSEL) based optical devices are shown, one of which incorporates an electro-absorption modulated laser (EML) based design. DETAILED DESCRIPTION

[0032] Figure 1A to Figure 1B An exemplary ultrafast modulated vertical cavity surface emitting laser (VCSEL) incorporating a Pockels material within an interdigitated grating to improve performance is shown in accordance with the present disclosure. Figure 1A to Figure 1B , a vertical cavity surface emitting laser (VCSEL) 100 (or a portion thereof) is shown having an interdigitated grating to provide ultrafast modulation.

[0033] In this aspect, the VCSEL 100 may include a semiconductor laser diode based structure configured to provide a laser beam emission perpendicular to the top surface. For example, the VCSEL may include a distributed Bragg reflector (DBR) based structure configured to act as a mirror parallel to the top surface, wherein the active region includes one or more quantum wells for generating laser light therebetween. A DBR structure may be disposed on top of a substrate layer and a heat sink layer. A planar DBR mirror may include layers having alternating high refractive index (RI) and low RI based materials.

[0034] The thickness of each layer can be set to form a high reflectivity. For example, a thickness of one quarter of the laser wavelength in the material can form an optical reflectivity of more than 99%. The use of high reflectivity can be used to balance the short axial length of the gain region. In some implementations, the p-type region and the n-type region can be embedded between the DBR mirrors to form a diode junction. This may involve more complex semiconductor processing to ensure electrical contact with the active layer / region, but can eliminate electrical power losses in the DBR structure. Figure 1A An exemplary structure of a VCSEL 100 is shown.

[0035] According to the present disclosure, the performance of VCSELs can be improved, particularly in terms of modulation functionality and / or characteristics thereof. Specifically, this can be achieved by making adjustments and / or additions to the structure of the VCSELs, which can provide improved performance without adding too much cost and / or complexity.

[0036] In this aspect, during operation of the VCSEL, the drive current may be modulated, which in turn modulates the output laser. However, the modulation of the VCSEL may sometimes be limited by different factors, including the time it takes for photons to escape from the cavity section of the VCSEL. While reducing the gain may help, doing so still requires some time for the photons to escape. This limits the modulation speed of the VCSEL. The solution according to the present disclosure allows for modulation faster than the photon escape time. This can be achieved, for example, by redirecting the beam to allow the photon escape time to be overcome.

[0037] For example, in various embodiments based on the present disclosure, an interdigital grating may be used in a VCSEL, such as Figure 1AIn this aspect, the interdigital grating may include a material filled with a Pockels material (i.e., a material with a high Pockels coefficient (e.g., Perkinamine for organic TM , KTO, etc.). The Pockels material can be selected based on predetermined selection criteria, such as ensuring that the high contrast grating allows the laser beam to be biased in the manner described herein. According to the Huygens-Fresnel principle, the use of cross-finger gratings can allow the generation of a "sub-λ" (or "smaller distance relative to the optical fiber") beam array that can output the top of a modulator with destructive interference in the far field. This can result in high (constructive) or low (destructive) power coupling into the optical fiber / coupling in the far field, such as by changing the bias applied between the two cross-finger gratings. As a second part, the effect can be enhanced by embedding the resonance effect into the cavity.

[0038] In some exemplary embodiments, a high contrast grating (HCG) based approach may be used. In this aspect, an HCG may be used to replace the top distributed Bragg reflector (DBR) layer of a vertical cavity surface emitting laser (VCSEL). In this aspect, any suitable high contrast grating (HCG) based design may be used that allows for the desired modulation speed increase to be achieved. Specifically, when selecting and configuring a high contrast grating (HCG) structure for use in a VCSEL to enhance its modulation performance, a key consideration may be the ability to apply bias voltage to the laser beam, apply gate tension, etc. For example, as Figure 1A As shown in the embodiment shown in , a high contrast grating (HCG) can include an etched structure, such as an "in-plane" periodic or quasi-periodic structure with alternating low refractive index (RI) and high RI, to achieve "out-of-plane" high reflectivity. In addition, contacts can be provided on top of the HCG structure (e.g. Figure 1A ). These contacts can effectively act as mirrors. The contacts can include metal or any suitable material. In some examples, the HCG structure can incorporate some DBR material above the active layer / region.

[0039] In some exemplary embodiments, a metal array may be used, such as contacts on top of the surfaces of the HCGs that are individually connected. Figure 1B, which shows a top view of a metal array disposed on top of a VCSEL. The metal array can be used as an interdigitated gate, where the etched high contrast grating (HCG) of the VCSEL is filled (e.g., at DOI:10.1038 / srep40348), where the holes are filled with Pockels material. In this aspect, the Pockels material does not need to meet specific filling criteria (e.g., it can be used to completely fill the holes, but this may not be necessary). Instead, other factors (such as the overlap between two different paths and the choice of the material used) may be relevant. In this aspect, the Pockels coefficient of the material should allow the laser beam to be biased, such as to ensure that destructive interference and constructive interference as described herein are produced. The metal lines of the metal array (i.e., the contacts on top of the HCG) can be connected to each other and to V2, and can be insulated by a thin insulating layer. Similarly, the Pockels material (path) that fills the holes of the HCG structure can be connected to each other and to V1. Then, by applying a bias on V2, half of the paths can be out of phase with respect to the other half, causing destructive interference.

[0040] However, the present disclosure is not limited to such designs, and solutions based on the present disclosure can be extended to gratings of any suitable shape, any material suitable for use therein, using (or not using) resonance effects to enhance the Pockels effect, etc.

[0041] Furthermore, while various aspects and features of the present disclosure are shown and described in terms of VCSEL-based implementations, the present disclosure is not limited to VCSELs, and similar designs described herein may be used in other types of optical emitting devices, such as photonic crystal surface emitting lasers (PCSELs) and high-order distributed feedback polymers (DFBs). Figures 2 to 4 Exemplary VCSELs, PCSELs, and high-order DFBs are shown and described, which may be configured to incorporate structural and / or functional modifications based on the present disclosure.

[0042] Figure 2 An exemplary vertical cavity surface emitting laser (VCSEL) is shown. Figure 2 , a vertical cavity surface emitting laser (VCSEL) 200 (or a portion thereof) is shown.

[0043] VCSELs are often used as light (e.g., laser) sources, especially in implementations such as transceivers (e.g., optical transceivers used in data centers). dc ) and communication (I ac ) to drive the VCSEL.

[0044] like Figure 2As shown in , VCSEL 200 includes a multi-quantum well (MQW) layer used as a gain medium sandwiched between two mirrors (e.g., distributed Bragg reflector (DBR) layers). In addition, VCSEL 200 includes contacts, such as located on the top side of the top mirror layer and / or at the bottom side of VCSEL 200. The contacts may include, for example, a metal material or the like.

[0045] Figure 3 An exemplary photonic crystal surface emitting laser (PCSEL) is shown. Figure 3 , a photonic crystal surface emitting laser (PCSEL) 300 (or a portion thereof) is shown.

[0046] PCSELs are often used as light (e.g., laser) sources and traditionally use direct current (I dc ) and communication (I ac ) to drive one or both of them.

[0047] like Figure 3 As shown in , PCSEL 300 includes a multi-quantum well (MQW) layer, which serves as a gain medium, sandwiched between a mirror (e.g., a distributed Bragg reflector (DBR)) layer located on the bottom and a photonic crystal layer located on top of the MQW layer. In addition, PCSEL 300 includes contacts, such as located on the top side of the top mirror layer and / or at the bottom side of PCSEL 300. The contacts may include, for example, a metal material, etc.

[0048] Figure 4 An exemplary high-order distributed feedback polymer (DFB) is shown. Figure 4 , a high-order distributed feedback polymer (DFB) 400 (or a portion thereof) is shown.

[0049] High-order DFBs are usually used as light (e.g., laser) sources and traditionally use direct current (I dc ) and communication (I ac ) to drive one or both of them.

[0050] like Figure 4 As shown in , the high-order DFB 400 includes a multi-quantum well (MQW) layer, which is used as a gain medium, sandwiched between a mirror (e.g., a distributed Bragg reflector (DBR)) layer located on the bottom and a high-order grating layer located on top of the MQW layer. In addition, the high-order DFB 400 includes contacts, such as located on the top side of the top mirror layer and / or at the bottom side of the high-order DFB 400. The contacts may include, for example, a metal material, etc.

[0051] Figures 2 to 4Each of the three different types of optical devices (VCSEL, PCSEL, and high-order DFB) shown in FIG. 5 is illustrated using bottom emission, since the solution based on the present disclosure can also be applied to bottom emission.

[0052] Figure 5A An exemplary vertical cavity surface emitting laser (VCSEL) based electro-absorption modulated laser (EML) according to the present disclosure is shown. Figure 5A , an electro-absorption modulated laser (EML) 500 (or a portion thereof) based on a vertical cavity surface emitting laser (VCSEL) is shown.

[0053] The VCSEL-EML 500 includes a multi-quantum well (MQW) layer used as a gain medium sandwiched between two mirrors (e.g., a distributed Bragg reflector (DBR) layer), wherein an electro-absorption modulated laser (EML) based structure is located on the top side of the top mirror layer. In addition, the VCSEL-EML 500 may include contacts, such as located on the top side of the EML based structure, on the top side of the top mirror layer, and / or on the bottom side of the VCSEL-EML 500. The contacts may include, for example, a metal material, etc.

[0054] VCSELs are often used as light (e.g., laser) sources, especially in such implementations as transceivers (e.g., optical transceivers used in data centers). Traditionally, direct-driven or DAC / DC-based VCSELs are used. However, such directly modulated VCSELs are very close to the bandwidth (BW) bottleneck between electrical bandwidth and optical bandwidth.

[0055] Thus, a VCSEL-EML device is used in which an EML-based structure is added for handling at least some of the modulation performed in the VCSEL. In this aspect, during an exemplary operation of the VCSEL-EML, a modulation voltage may be applied to the EML-based structure and then a current is provided to drive the device as a whole. For example, a time-varying voltage may be used to drive the device, which allows digital-based driving (e.g., switching on or off based on a voltage), such as a digital signal that modulates the output optical signal. Alternatively, the device may be driven by direct current (DC) so that it is always on. For example, as Figure 5A As shown in the figure, in VCSEL-EML 500, V ac Used to drive EML-based structures, while I dc For the drive unit (as a whole).

[0056] According to the present disclosure, the performance of a VCSEL-EML (e.g., VCSEL-EML 500) can be improved and / or optimized, in particular by modifying the EML-based structure used therein. For example, the VCSEL-EML can be modified, such as by incorporating a vertical EML that uses and / or exploits the Pockels effect, to achieve a new modulation scheme. In this aspect, in such an implementation, the VCSEL can be used as a continuous waveform (CW) light source, where the proposed EML-based structure is monolithically implemented on top of the top mirror (e.g., DBR) layer of the VCSEL. In addition, the EML can be modified to improve the performance of the EML and the device as a whole, in particular by incorporating a Pockels material to exploit the Pockels effect.

[0057] In this regard, the Pockels effect is a direction-dependent linear change in the refractive index (RI) of an optical medium that occurs in response to an applied electric field. The refractive index of an optical medium is a dimensionless number that indicates the light bending ability of the medium. In other words, the refractive index is an indication of the speed of light in a material. Therefore, in various implementations, a Pockels material is added to an EML-based structure to enable modulation of light based on the refractive index (RI) of the material (e.g., by controlling a voltage applied across the Pockels material), which in turn affects the behavior of the light beam when applied to the EML-based structure.

[0058] Such an approach can be material agnostic, for example, by exploiting adaptability of biasing schemes on EML-based structures. In this regard, as described herein, the Pockels materials used in the EML can be adaptively selected and / or applied to ensure that specific performance criteria (e.g., determined by a desired or required RI) are met. Furthermore, in many instances, the added Pockels materials can be used in conjunction with a biasing scheme (applied to the EML-based structure), where the biasing scheme is adapted to the desired modulation function.

[0059] For example, Figure 5A As shown in , VCSEL-EML 500 is implemented as an integrated 3-contact VCSEL with a laser-DC drive separated from the modulation drive. This allows the use of EML electronic solutions that directly drive the modulation portion. Incorporating Pockels materials into EML-based structures allows for improved performance based on the adaptive use of the Pockels effect. Specifically, Pockels materials can be used to form and / or utilize sub-wavelength patterns to enhance the Pockels effect.

[0060] In various example implementations, the EML may incorporate gratings configured to support modulation functionality that incorporate Pockels materials to exploit the Pockels effect. For example, in some implementations, incorporation of Pockels materials may be accomplished in conjunction with the use of high contrast gratings (HCGs). In this regard, use of high contrast gratings (HCGs) may be desirable because it may provide various advantages, such as limited optical losses (e.g., << 3dB), the ability to use high Pockels materials, the ability to use readily available HCG simulation capabilities, etc. In some instances, etched structures of high refractive index materials (e.g., 50nm to 100nm wide and 200nm to 400nm deep) may be utilized.

[0061] Depending on the configuration, the proposed EML-based structure can be used to provide various modulation functions. For example, the EML can be used to modulate the output power (intensity modulation or amplitude modulation), modulate the deflection of the beam (e.g., output coupling into an optical fiber (wavefront modulation)), and / or modulate the polarization of the beam (polarization modulation).

[0062] In some instances, the proposed EML-based structure can be configured to meet specific performance criteria. For example, the EML can have a target V π <<5V. Meeting such performance criteria may require designing and / or configuring the EML-based structure accordingly. For example, ensuring that such a target V π Light field enhancement in, for example, a Pockels material may be desired.

[0063] In some instances, the proposed EML-based structure can be used for other applications, such as components for providing 100sGbps (e.g., passive optical network (PON) elements (located at the fiber tip, vertical modulators / couplers, etc.), MUX / DEMUX functions, etc.), for beam steering (e.g., as ultrafast spatial light modulators), etc.

[0064] In some implementations, the proposed EML-based structure can be used in conjunction with a photonic crystal surface emitting laser (PCSEL) light source (rather than a VCSEL). Using a PCSEL as a light source can be beneficial, such as the benefit of optimizing HCG design possibilities. In this regard, the PCSEL can be the best light source because it is an inherently single-mode device, can allow the full potential of the high-Q resonance of the HCG to be utilized, and / or can allow uniform illumination of the HCG (which allows avoiding detrimental HCG finite size effects).

[0065] Figure 5B An exemplary 3-contact vertical cavity surface emitting laser (VCSEL) based electro-absorption modulated laser (EML) according to the present disclosure is shown. Figure 5B, an electro-absorption modulated laser (EML) 520 (or a portion thereof) based on a vertical cavity surface emitting laser (VCSEL) is shown.

[0066] In this aspect, the VCSEL-EML 520 may be substantially similar to Figure 5A The VCSEL-EML 500 is a VCSEL-EML 520 and can operate in substantially the same manner. Specifically, the VCSEL-EML 520 includes an electro-absorption modulated laser (EML) based structure located on top of a general vertical emitting laser structure. The general vertical emitting laser structure can include any suitable structure that can be configured to enable vertical lasing. For example, the general vertical emitting laser structure can have a structure similar to Figure 5A The corresponding structure in the VCSEL-EML 500 is similar in structure and may also include a multiple quantum well (MQW) layer used as a gain medium sandwiched between two mirrors (eg, distributed Bragg reflector (DBR) layers).

[0067] In addition, VCSEL-EML 520 may include contacts, such as on the top side of the EML-based structure, on the top side of the universal vertical emitting laser structure, and / or on the bottom side of the universal vertical emitting laser structure. The contacts may include, for example, a metal material or the like.

[0068] VCSEL-EML 520 represents an alternative design utilizing 3 contacts. Figure 5B In the implementation shown in FIG. 1 , the three contacts may correspond to contacts located on the top side of the EML-based structure, contacts located on the top side of the universal vertical emitting laser structure, and contacts located on the bottom side of the universal vertical emitting laser structure, respectively. dc and / or V ac To drive these three contacts.

[0069] Figure 5C An exemplary 4-contact vertical cavity surface emitting laser (VCSEL) based electro-absorption modulated laser (EML) according to the present disclosure is shown. Figure 5C , an electro-absorption modulated laser (EML) 540 (or a portion thereof) based on a vertical cavity surface emitting laser (VCSEL) is shown.

[0070] In this aspect, the VCSEL-EML 540 may be substantially similar to Figure 5AThe VCSEL-EML 500 is a VCSEL-EML 540 and can operate in substantially the same manner. Specifically, the VCSEL-EML 540 includes an electro-absorption modulated laser (EML) based structure on top of a generic vertical emitting laser structure with an electrically insulating layer therebetween. The generic vertical emitting laser structure may include any suitable structure that can be configured to emit laser light vertically. For example, the generic vertical emitting laser structure may have a structure similar to Figure 5A The VCSEL-EML 500 has a similar structure to the corresponding structure thereof and may also include a multiple quantum well (MQW) layer used as a gain medium sandwiched between two reflectors (eg, distributed Bragg reflector (DBR) layers).

[0071] In addition, VCSEL-EML 540 may include contacts, such as on the top side of the EML-based structure, on the top side of the universal vertical emitting laser structure, and / or on the bottom side of the universal vertical emitting laser structure. The contacts may include, for example, a metal material or the like.

[0072] VCSEL-EML 540 represents an alternative design utilizing 4 contacts. Figure 5C In the implementation shown in , the four contacts may correspond to contacts located on the top side of the EML-based structure, contacts located on the top side of the universal vertical emitting laser structure, and contacts located on the bottom side of the universal vertical emitting laser structure, respectively, wherein the contacts located on the top of the EML-based structure are configured into two separate contact groups, such as Figure 5C As shown in the . Use I dc and / or V ac To drive these 4 contacts.

[0073] Figure 6 An exemplary high contrast grating (HCG) structure according to the present disclosure is shown. Figure 6 , a vertical cavity surface emitting laser (VCSEL) 600 incorporating a high contrast grating (HCG) 610 is shown.

[0074] The VCSEL 600 includes two mirrors with an active layer (eg, MQW) sandwiched between them, wherein the top mirror incorporates the HCG 610. The bottom mirror and the top mirror having the grating structure in combination with the active layer form a laser resonator.

[0075] As described above, in some examples, a high contrast grating (e.g., HCG 610) may be used in a vertical cavity surface emitting laser (VCSEL) based electro-absorption modulated laser (EML) based on implementations of the present disclosure, wherein the HCG is specifically used in the proposed EML based structure for facilitating and / or supporting the modulation function performed thereby. In this aspect, the grating incorporates grating features with gaps therebetween, and may be characterized by dimensions such as the height of the grating features (dimension h), the width of the grating features (dimension a), the thickness of the contacts on top of the grating features (dimension h), and the thickness of the contacts on top of the grating features (dimension h). M ), the period of the grating features (i.e., the distance between identical points in consecutive grating features (dimension d), and the total depth of the gap (dimensions h and h when the contacts are placed on top of the grating features). M Combinations such as Figure 6 It is characterized by the parameters shown in .

[0076] High contrast gratings such as HCG 610 may incorporate grating features with sub-wavelength dimensions and may have a strong refractive index contrast (e.g., the refractive index of the grating in air is >1.7). The high contrast may be provided by the gaps, which may be filled (e.g., with air having a very low RI), thereby causing a high contrast between the gaps and the grating structure features. In this aspect, the grating features are tall (and thus the gaps are deep). In other words, in order to observe the mirror effect, the gaps may generally be deeper than they are wide.

[0077] A high contrast grating such as HCG 610 can exhibit two modes: reflection (mode 0) and transmission (mode 2), where an incident wave (coming from inside the device, applied to the HCG from below after propagating through the underlying substrate) is reflected in mode 0 and passes through (as an output wave) in mode 2, as shown in FIG. Figure 6 620). In this aspect, the reflection / transmission modes can be coupled to each other and to the plane wave. The transmission mode (mode 2) can be determined by destructive interference between grating features. For example, in a 50 / 50 coupling (e.g., the geometry of the HCG), destructive interference can be determined by Δβ / λ=π.

[0078] In various instances, high contrast gratings can have two basic features: 1) only a few modes can be excited and coupled outward from the outside as "plane waves", and 2) the modes can be compressed in space, resulting in higher lateral momentum. Regarding feature 1, the HCG cuts high spatial frequency components. In this way, 2 or 3 modes of the HCG are sufficient to predict the general behavior, and the other mode is usually short-lived. In this regard, such other modes can be located below the light cone and can be entered into the 2nd order when estimating the reflection / transmission properties at the interface of the HCG with air. Regarding feature 2, the propagation constant is reduced and destructive interference between modes can be obtained (for example, for structures at <~ wavelengths).

[0079] High contrast gratings can exhibit different performance characteristics at different wavelength ranges. For example, for subwavelength sizes, there may be only one mode in the structure, and Fabry-Perot (FP) nodes / antinodes can be seen as the thickness of the HCG increases. For superwavelength sizes, there can be many modes that periodically restore the input signal in a manner / mode similar to the Talbot effect. In between these two ranges, there can be a small number of modes. Moreover, at specific locations, the two modes can resonate in the HCG at the same time. For example, for a 2nπ phase difference, energy can be trapped inside the HCG and there can be a large field enhancement (e.g., 1e3) and it can behave as an anti-crossing. Due to the (2n+1)π phase difference, part of the energy can be reflected back from the HCG.

[0080] In addition to being used to provide optical resonance in devices such as VCSELs, high contrast gratings can also be used in other applications such as beam manipulation (e.g., lenses, polarization, diffractive elements), waveguides (e.g., MMI, spot size converters, etc.), high broadband reflectivity, broadband AR coatings, nonlinear optics, bio- or chemical sensing, etc.

[0081] In implementations based on the present disclosure, Pockels material may be incorporated into the HCG structure, for example by using the Pockels material to fill at least some of the gaps between grating features and / or to form grating features (e.g., contacts are located on top). In this aspect, the use of the Pockels material may allow for improved operation of the HCG structure, particularly with respect to its modulation functionality. This is described in more detail below.

[0082] Figure 7 The use of an exemplary high contrast grating (HCG) structure as a reflectivity modulator according to the present disclosure is shown. Figure 7 , a vertical cavity surface emitting laser (VCSEL) 700 incorporating a high contrast grating (HCG) is shown.

[0083] VCSEL 700 may correspond to an electro-absorption modulated laser (EML) based on a vertical cavity surface emitting laser (VCSEL) implemented according to the present disclosure, wherein HCG is used in the proposed EML-based structure for facilitating and / or supporting the modulation functions performed thereby. Figure 7 The application of HCG is shown in FIG, ie, using HCG as a reflectivity modulator in an EML-based structure.

[0084] Such reflectivity modulators can exhibit high field enhancement. For example, for a grating using silicon, at 2V "V π "There can be a 30-fold field enhancement under . In addition, in some instances, various aspects or features can be modified to further enhance performance. For example, in some instances, dimerized HCG (rather than conventional HCG) can be used for better control. In addition, different materials can be used in the grating structure, such as by using BaTiO3 or organic materials instead of silicon, which can result in higher tunability.

[0085] In an exemplary operation of such a reflectivity modulator, for a beam propagating through the HCG (grating), if the beam has the correct wavelength (and / or if the grating is designed correctly), the light field will have a huge enhancement. The electric field of the incident beam between the gratings is large compared to the electric field of the incident beam before passing through the gratings. Similarly, for a beam with the correct wavelength, the structure becomes reflective. The resonant frequency (where the beam is reflected rather than modulated) can be controlled by adjusting the voltage applied to the grating. This is shown in an exemplary use scenario 710 in a VCSEL 700 and captured in a graph 720 showing transmittance as a function of wavelength.

[0086] In implementations based on the present disclosure, reflectivity modulation can be further enhanced by incorporating Pockels materials into HCG structures (e.g., within gaps between features (etches)), by forming features using Pockels materials with contacts on top, etc.

[0087] Figure 8 An exemplary high contrast grating (HCG) structure is shown for use in wavefront modulation according to the present disclosure. Figure 8 , a high contrast grating (HCG) 800 is shown.

[0088] The HCG 800 may be used with a vertical cavity surface emitting laser (VCSEL) based electro-absorption modulated laser (EML) based on implementations of the present disclosure, wherein the HCG is used in the proposed EML based structure for facilitating and / or supporting the modulation functions performed thereby. Figure 8An application of HCG is shown in FIG, ie, using HCG 800 as a wavefront modulator in an EML-based structure.

[0089] In this regard, in an exemplary operation of such a wavefront modulator, the HCGs may be biased in groups (ie, groups of gratings in an HCG structure), such as Figure 8 Such a bias allows the beam to be deflected to discrete angles. The angles may be defined, for example, by the discrete geometry of the HCG structure. In some examples, the angle of deflection (or diffraction of an external incident beam) may be tunable, such as Figure 8 (810) and captured in graph 820, which shows the normalized angular intensity distribution based on using the proposed exemplary EML-based structure.

[0090] In implementations based on the present disclosure, wavefront modulation can be further enhanced by incorporating Pockels materials into HCG structures (e.g., within gaps between features (etches)), by forming features using Pockels materials with contacts on top, etc.

[0091] Fig. 9 The use of an exemplary vertical cavity surface emitting laser (VCSEL) based electro-absorption modulated laser (EML) as an intensity modulator in accordance with the present disclosure is shown, the VCSEL based EML incorporating a high contrast grating (HCG) with a Pockels material. Fig. 9 , a high contrast grating (HCG) 900 is shown.

[0092] As described above, in some instances, a high contrast grating may be used in a vertical cavity surface emitting laser (VCSEL) based electro-absorption modulated laser (EML) implemented according to the present disclosure, wherein the HCG 900 is configured for such use in the proposed EML based structure to facilitate and / or support the modulation functionality performed thereby.

[0093] like Fig. 9 As shown in , HCG 900 may incorporate two contacts that may be arranged in a staggered manner (as shown in plan view, i.e., looking toward the top of the structure), thereby forming an interdigitated gate grid. HCG 900 may also include a Pockels material. In this aspect, Fig. 9 In the embodiment shown in , the Pockels material is used to fill the gap between two contacts. However, the present disclosure is not limited to such a method, and as such, the arrangement of the contacts and / or the arrangement of the Pockels material may be performed in any suitable manner. For example, in Fig.13 An alternative design is shown in , where the contacts are located on top of the Pockels material.

[0094] Separate voltages (V1 and V2) can be applied to the two contacts to create a specific bias in the HCG. In this aspect, the interdigitated grid allows an electric field to be generated through the Pockels material between two different grating elements (corresponding to the locations of the contacts to which V1 and V2 are applied). The two contacts are not (necessarily) made of different materials; rather, applying different voltages to the contacts will generate different electric fields.

[0095] like Fig. 9 As shown in , the interdigitated bias grating generates a transverse electric field, that is, the direction of the electric field through the Pockels material can be alternated due to the staggered arrangement (as shown in the figure). The interdigitated bias grating can also periodically modify the refractive index (RI) of the HCG structure as a whole. In this aspect, the RI in the grating can be modified by changing the electric field applied to the Pockels material. Since the RI determines the speed of light, modifying the RI changes the phase of the light passing through the grating.

[0096] The use of Pockels materials can further enhance the performance. For example, Pockels materials (and their corresponding Pockels effect) can be combined with resonance enhancement (from grating features) to maintain low V π In this aspect, the Pockels effect itself may be too small to achieve the desired π phase transition, and thus the resonance may also be used to achieve the desired optical field enhancement. Thus, achieving the desired Pockels effect may be achieved by providing a resonant field enhancement rather than by increasing the voltage. In other words, the resonance from the grating structure may be used to increase the intensity of the optical field, and thus enhance the Pockels effect (without increasing the voltage applied to the grating).

[0097] As mentioned above, the use of HCG in the proposed EML-based structure can allow the achievement of low target V π (e.g. << 5V). In this aspect, in the absence of cavity or resonance effects, the following formula can be used to determine the tilt angle (θ):

[0098]

[0099] where h is the height of the material and d is the grating period. Without field enhancement, the effect would probably be too small.

[0100] For example, for n = 2, ΔV = 5V, r 33 =700 pm / V, h=1 um, and d=100 nm, sin(θ)=1.4e-2. To enhance by ~10 to 100, other measures may be needed, such as vertical DBR cavities, plasmon resonance from gratings, and high contrast gratings (HCG). In this regard, HCG can provide local ×10 3Field enhancement. Compared to an optical microcavity, the electric field (E) used in an HCG is similar, but the applied bias is much lower (because the distance between the electrodes is very small). However, in some instances, an HCG can be combined with a DBR cavity to obtain even higher nonlinear effects.

[0101] like Figure 6 As shown in , an EML-based structure incorporating HCG 900 (eg, used in a VCSEL-EML device) can be used as an intensity (amplitude) modulator. However, the EML-based structure can also be used to provide other functions, such as wavefront modulation, reflectivity modulation, etc.

[0102] In some implementations, an EML-based structure with an HCG incorporating a Pockels material (e.g., used in a VCSEL-EML device) can be used to provide polarization rotation. In this aspect, the grating features are inherently linear polarizers and will therefore selectively transmit light beams having polarization in a particular direction (e.g., the x-direction). The structure can be configured to provide polarization rotation, which can be used, for example, to block beams. Using polarization rotation in this manner can be combined with or as an alternative to the use of refractive index-related features.

[0103] Fig.10 Different processes for fabricating a vertical cavity surface emitting laser (VCSEL) based electro-absorption modulated laser (EML) incorporating a high contrast grating (HCG) with a Pockels material according to the present disclosure are shown. Fig.10 , two different fabrication processes 1000 and 1010 are shown for fabricating a VCSEL-EML with a high contrast grating (HCG) structure using Pockels materials.

[0104] In this aspect, different methods (processes) may be used when manufacturing an optical device (e.g., a VCSEL) having an EML-based structure that incorporates a HCG having a Pockels material, and the present disclosure is not limited to a particular method or approach. The manufacturing method may vary depending on the deposition technique used when applying the Pockels material. The manufacturing method may also be affected by the HCG design (e.g., with respect to the arrangement of contacts used therein). For example, when interdigitated contacts are used, several physical implementations may be used (as described in more detail below), and the manufacturing method may need to be adapted for use with such an arrangement. In this way, the manufacturing method may vary in the manner in which the Pockels material is applied to the specific grating (HCG) structure used.

[0105] For example, Fig.10As shown in , the process can be "top-down" or "bottom-up" depending on the deposition technique of the Pockels material. In this aspect, in process 1000, a layer of Pockels material is first laid down on an insulating layer. The layer of Pockels material is then etched to create spaces for contacts, and then the contacts are added. In process 1010, contacts are first applied to an insulating layer with spaces between the contacts based on a predetermined staggered arrangement including spaces between the contacts. A layer of Pockels material is then deposited or formed into the spaces between the contacts.

[0106] In some examples, the process used in manufacturing the VCSEL-EML can be configured to meet predetermined criteria (e.g., dimensions of the final structure, such as about ~250nm deep, openings in the range of 50nm to 100nm, etc.). Thus, manufacturing the HCG structure involves adding and / or depositing ~250nm to make the HCG on top (either only in specific areas (space in a bottom-up process) or over the entire surface), and then removing part of the applied layer (e.g., by etching stop).

[0107] Implementing a Pockels material (i.e., applying it to a grating structure) can be done in a variety of ways, and the present disclosure is not limited to any particular method, and in so doing, any suitable method can be utilized. For example, a Pockels material can be implemented using processing at the wafer bonding level (e.g., using BTO, Li.Nb, BaTiO3, etc.). A Pockels material can be implemented at or near the end of a process (e.g., using an organic, BTO-based suspension, etc.).

[0108] Fig.11 Dephasing in an exemplary vertical cavity surface emitting laser (VCSEL) based electro-absorption modulated laser (EML) incorporating a high contrast grating (HCG) with a Pockels material according to the present disclosure is shown. Fig.11 , shows a VCSEL-EML 1100 incorporating an HCG structure with a Pockels material in the gap between contacts. The VCSEL-EML 1100 may be substantially similar to that described with respect to Fig. 9 VCSEL-EML 900 described.

[0109] exist Fig.11 Dephasing in a VCSEL (such as VCSEL-EML 1100) is shown in FIG. In this aspect, dephasing may occur due to voltage differences between interdigitated gates, which may produce periodic changes in the refractive index (RI) in the structure. For example, the RI may be modified by controlling (setting and / or changing) the electric field applied to the Pockels material. Since the RI determines the speed of light, modifying the RI changes the phase of the light passing through the grating.

[0110] In a VCSEL incorporating two contacts (e.g., VCSEL-EML 1100), dephasing can be performed by adjusting the voltages applied to the two contacts. In this aspect, when the voltages in the two contacts are the same (i.e., in the case of V1=V2), the contacts will be in phase, and the interference will be vertically constructive, while when the voltages are not the same (i.e., V1≠V2), a periodic change in the refractive index may occur, causing vertical destructive interference and thus dephasing the contacts (gates).

[0111] Fig.12 An exemplary vertical cavity surface emitting laser (VCSEL) based electro-absorption modulated laser (EML) incorporating a high contrast grating (HCG) with a Pockels material is shown for use in wavefront modulation according to the present disclosure. Fig.12 , shows a VCSEL-EML 1200 incorporating a HCG structure with Pockels material in the gap between contacts.

[0112] The VCSEL-EML 1200 may be substantially similar to the Fig. 9 VCSEL-EML 900 as described. Fig.12 As shown in , the VCSEL-EML 1200 can be used as a wavefront modulator. In this aspect, the refractive index (RI) can be modified based on changing the electric field applied to the Pockels material at different contacts. As mentioned above, the RI determines the speed of light, and therefore modifying the RI changes the phase of the light passing through the grating. Therefore, as Fig.12 As shown in , when the Pockels materials are subjected to the same voltage, the contacts are in phase, and when the voltages are different the contacts are out of phase.

[0113] In various implementations, several sub-wavelength gratings can share the same bias voltage. This allows the output wave to stay in the light cone while creating dephasing between groups or gratings. However, using a Pockels-based EML (e.g., such as Fig.12 The VCSEL-EML 1200) as a wavefront modulator may be limited to certain types of Pockels materials. For example, only Pockels materials with a strong r42 can be used.

[0114] Fig.13 An exemplary vertical cavity surface emitting laser (VCSEL) based electro-absorption modulated laser (EML) incorporating a high contrast grating (HCG) with a Pockels material on top of the contacts is shown for use in wavefront modulation according to the present disclosure. Fig.13 , shows a VCSEL-EML 1300 incorporating a HCG structure having a Pockels material.

[0115] The VCSEL-EML 1300 may be substantially similar to Fig. 9 However, as Fig.13 As shown in , the VCSEL-EML 1300 may differ in that the contacts are arranged on top of the Pockels material. Fig.13 As shown in FIG. 1 , VCSEL-EML 1300 can be used as a wavefront modulator. In this aspect, when used as a wavefront modulator, VCSEL-EML 1300 can operate in a substantially similar manner to VCSEL-EML 1200, as described with respect to FIG. Fig.12 Specifically, in VCSEL-EML 1300, the refractive index (RI) can also be modified based on changing the electric field applied to the Pockels material, however, here the electric field is applied from the substrate through the Pockels material to the contacts on top of the Pockels material. As described above, modifying the RI changes the phase of the light passing through the grating, with the contacts being in phase when subjected to the same voltage and out of phase when subjected to different voltages, such as Fig.13 as shown in .

[0116] Fig.14 The processing of an exemplary vertical cavity surface emitting laser (VCSEL) based electro-absorption modulated laser (EML) having a high contrast grating (HCG) incorporating a Pockels material according to the present disclosure is shown. Fig.14 , shows a VCSEL-EML 1400 incorporating a HCG structure having a Pockels material located in the gap between contacts.

[0117] The VCSEL-EML 1400 may be substantially similar to Fig. 9 VCSEL-EML 900 is described. However, the high contrast grating (HCG) structure in VCSEL-EML 1400 may include different materials, such as aluminum gallium arsenide (AlGaAs). Such a design (method) may have various benefits, such as being small, ultrafast, having low losses, allowing wavelength tuning by grating rather than material (e.g., coarse wavelength division multiplexing (CWDM) or dense wavelength division multiplexing (DWDM) on the same array). Using an external laser source (e.g., a comb laser) may allow high temperature / low power data transmission.

[0118] exist Fig.14The processing of an incoming beam (light) projected onto the VCSEL-EML 1400 from the outside (rather than from the bottom through the substrate) is shown in FIG. In this aspect, due to dephasing, the absorption resonance of the HCG in the VCSEL-EML 1400 can be slightly adjusted, causing a change in reflectivity. In this way, when the voltages applied to the contacts are different, the contacts will be out of phase, causing the incoming light to be reflected back at a specific angle, such as Fig.14 as shown in .

[0119] Fig.15 An exemplary vertical cavity surface emitting laser (VCSEL) based electro-absorption modulated laser (EML) incorporating a high contrast grating (HCG) with a Pockels material is shown for use in polarization modulation according to the present disclosure. Fig.15 , a VCSEL-EML 1500 is shown.

[0120] The VCSEL-EML 1500 may be substantially similar to the Fig. 9 However, as Fig.15 As shown in , the VCSEL-EML 1500 may differ in that contacts (eg, metal contacts) are provided on top of the Pockels material. Fig.15 As shown in , VCSEL-EML 1500 can be used as a polarization modulator. However, the polarization modulation described herein is not limited to a specific implementation corresponding to VCSEL-EML 1500, and such polarization modulation can be applied to and / or provided by any of the proposed EML-based structures disclosed herein.

[0121] In this aspect, the HCG can have strong birefringence between the transverse electric (TE) mode and the transverse magnetic (TM) mode. In this way, the design and / or implementation of the device can be adapted to exploit such properties to provide polarization modulation through the proposed EML-based structure (incorporating Pockels material). This can be feasible for any of the implementations disclosed herein. Polarization modulation can be provided by utilizing, for example, a cross-digital contact arrangement in the proposed EML structure. In this way, the same principles and methods used in wavefront modulation can be used for polarization modulation, for example by connecting all teeth of the HCG to the same bias source. Polarization modulation can be considered as a subset of amplitude modulation schemes.

[0122] For example, polarization modulation can be achieved by applying modulation to allow or inhibit the mode inside the HCG. In this aspect, the HCG properties can be mirror-changed near the mode cutoff, as shown in graphs 1510 and 1520, which show a sudden change in TE reflectivity and a sudden change in TM reflectivity and an overlapping region. In this aspect, at overlapping transition frequencies (e.g., for TM6 / TE6), both polarizations can have a strong sensitivity to refractive index changes. The EML structure can be modified to optimize polarization modulation. For example, when the bias voltage is changed, the appropriate thickness of the HCG can allow identification of a point where TE reflectivity increases as TM reflectivity decreases (or vice versa).

[0123] Fig.16 An exemplary variation of a high contrast grating (HCG) structure with a Pockels material according to the present disclosure is shown. Fig.16 , showing various variations of HCG with Pockels materials. Specifically, in Fig.16 HCGs 1600, 1610, 1620, 1630, 1640, and 1650 are shown in FIG. In this regard, HCG 1600 represents a basic implementation, and HCGs 1610, 1620, 1630, 1640, and 1650 represent alternative variations of the basic implementation.

[0124] Variations of the basic implementation (HCG 1600) may include dimerized versions of the HCG. In this regard, lower resonant frequencies may be possible for such variations. Such variations may come in different styles. For example, this may be accomplished by changing geometric parameters (such as the width of the high or low refractive index material, as shown in HCG 1640 (Variant 1)), by changing the material every two teeth, (such as shown in HCG 1640 (Variant 2)), or by connecting every two teeth, (such as shown in HCG 1640 (Variant 3)).

[0125] The patterns of HCG can also vary spatially, for example based on pattern changes in the x or y direction. This can include slow shifts in resonance over space (e.g., less than 1% change in λ, as shown in HCG 1640 (Variant 4)) or sudden shifts in HCG parameters (e.g., one or more parameters have a 1% change between one repeat of the motif and the next, but the geometry is stable over more than 10λ, as shown in HCG 1640 (Variant 5)).

[0126] Fig.17 A first exemplary implementation of a structure based on an interdigital electro-absorption modulated laser (EML) according to the present disclosure is shown. Fig.17 , shows an EML-based structure 1700. Specifically, Fig.17 1 shows a top view 1710 of an EML-based structure 1700 and a side view 1720 corresponding to a specific cross-section (line) in the structure.

[0127] As shown in the side view 1720, the EML-based structure 1700 includes a common vertical emitting layer followed (in the z direction) by an insulating layer (i.e., with an insulating layer on top), and then a high contrast grating (HCG) including two contacts (V1 and V2) comprising a semiconductor (e.g., doped semiconductor) material with a metal on top, wherein a Pockels material is disposed between the contacts. The contacts are (optionally) covered by a cap layer (not shown in the top view 1710).

[0128] The universal vertical emission layer may include any suitable structure that can be configured to emit lasers vertically. In an exemplary implementation, the universal vertical emission layer may include a substrate that may be optionally sandwiched between two vertical emission epitaxial stack layers. In this aspect, the epitaxial stack may include a VCSEL or a PCSEL (or a 2nd order, 3rd order, ..., nth order distributed feedback laser (DFB)). The substrate may include suitable materials such as gallium arsenide (GaAs), gallium nitride (GaN), indium phosphide (InP), silicon (Si), silicon carbide (SiC), etc.

[0129] The insulating layer may include a semiconductor (doped or undoped current blocking layer) or a ceramic (aluminum oxide AlO x , silicon nitride (SiN), silicon oxide (SiO2), etc.). The Pockels material may include a large r33 material.

[0130] The metal used in the contacts may include gold (Au), silver (Ag), copper (Cu), or a transparent conductive material such as, for example, indium tin oxide (ITO).

[0131] The Pockels material used in this implementation may need to have a low refractive index (e.g., IR<2), such as a polymer. Fig.17 In the exemplary implementation shown in , the doped semiconductor (contact) may be partially or completely covered in the y direction. The balance between optical loss and RF electrical loss depends on the specific application. As described above, a vertical emission epitaxial stack layer may or may not be included between the substrate and the EML or below the substrate.

[0132] Fig.18 A second exemplary implementation of a structure based on an interdigital electro-absorption modulated laser (EML) according to the present disclosure is shown. Fig.18 , shows an EML-based structure 1800. Specifically, Fig.18 1 , a top view 1810 of an EML-based structure 1800 and a side view 1820 corresponding to a specific cross section (line) in the structure are shown.

[0133] As shown in the side view 1820, the EML-based structure 1800 includes a common vertical emitting layer followed (in the z-direction) by an insulating layer (i.e., with an insulating layer on top), and then a high contrast grating (HCG) including two contacts (V1 and V2) with a Pockels material disposed between the contacts. The contacts are (optionally) covered by a cap layer (not shown in the top view 1810).

[0134] The universal vertical emission layer may include any suitable structure that can be configured to enable vertical laser emission. In an exemplary implementation, the universal vertical emission layer may include a substrate that may be optionally sandwiched between two vertical emission epitaxial stack layers. The epitaxial stack may include a VCSEL or a PCSEL (or a 2nd order, 3rd order, ..., nth order distributed feedback laser (DFB)). The substrate may include suitable materials such as gallium arsenide (GaAs), gallium nitride (GaN), indium phosphide (InP), silicon (Si), silicon carbide (SiC), etc.

[0135] The insulating layer may include a semiconductor (doped or undoped current blocking layer) or a ceramic (aluminum oxide AlO x , silicon nitride (SiN), silicon oxide (SiO2), etc.).

[0136] The Pockels material may include a large r33 material. In implementation 1800, the contacts (V1 and V2) may include a transparent metal (eg, silver nanowires (AgNW), CN, a mixture, etc.) with a low refractive index n<1.6.

[0137] The P Pockels material used in this implementation may need to have a high refractive index > 2 (e.g., SBN60, BaTiO3, etc.) In addition, as with the previous implementation, a vertically emitting epitaxial stack layer disposed between the substrate and the EML or below the substrate may or may not be included.

[0138] Fig.19 A third exemplary implementation of a structure based on an interdigital electro-absorption modulated laser (EML) according to the present disclosure is shown. Fig.19 , shows an EML-based structure 1900. Specifically, Fig.19 1 shows a top view 1910 of an EML-based structure 1900 and a side view 1920 corresponding to a specific cross section (line) in the structure.

[0139] As shown in the side view 1920, the EML-based structure 1900 includes a common vertical emission layer followed (in the z direction) by a lateral contact layer (i.e., with a lateral contact layer on top), and then a high contrast grating (HCG) comprising two contacts (V1 and V2) comprising a semiconductor (e.g., doped semiconductor) material with a metal on top, wherein a Pockels material is disposed between the contact metal on top of the Pockels material, and an undoped semiconductor material is disposed between the contacts, particularly the Pockels material, as shown. The contacts are (optionally) covered by a cap layer (not shown in the top view 1910).

[0140] The universal vertical emission layer may include any suitable structure that can be configured to enable vertical laser emission. In an exemplary implementation, the universal vertical emission layer may include a substrate that may be optionally sandwiched between two vertical emission epitaxial stack layers. The epitaxial stack may include a VCSEL or a PCSEL (or a 2nd order, 3rd order, ..., nth order distributed feedback laser (DFB)). The substrate may include suitable materials such as gallium arsenide (GaAs), gallium nitride (GaN), indium phosphide (InP), silicon (Si), silicon carbide (SiC), etc.

[0141] The lateral contact layer may include a transparent and conductive material. The Pockels material may include a Pockels material such as R42, 63, etc. The metal of the contact may include gold (Au), silver (Ag), copper (Cu) or a transparent conductive material (e.g., such as indium tin oxide (ITO)).

[0142] The Pockels material used in this implementation may need to have a low refractive index (e.g., IR<2), such as KDP, polymers, etc. In some instances, in this implementation, a bias may be applied to the lateral contact layer so that 3 different biases are applied. However, in many instances, the bias applied to the lateral contact layer may be the same as the bias applied to one of the contacts (e.g., V3=V2=0). In addition, as with the previous implementation, a vertically emitting epitaxial stack layer located between the substrate and the EML or below the substrate may or may not be included.

[0143] Fig. 20 A fourth exemplary implementation and a fifth exemplary implementation of a structure based on an interdigital electro-absorption modulated laser (EML) according to the present disclosure are shown. Fig. 20 , showing EML-based structures 2000 and 2010 (each viewed from the side).

[0144] like Fig. 20As shown in , the EML-based structures 2000 and 2010 include a common vertical emission layer followed (in the z direction) by a lateral contact layer (i.e., with a lateral contact layer on top), and then a high contrast grating (HCG) comprising two contacts (V1 and V2) comprising a semiconductor (e.g., doped semiconductor) material with a metal on top, wherein the contact metal is located on top of the Pockels material, and undoped semiconductor material is disposed between the contacts, particularly the Pockels material, as shown. The contacts are (optionally) covered by a cap layer (not shown in the top view 2010).

[0145] The universal vertical emission layer may include any suitable structure that can be configured to enable vertical laser emission. In an exemplary implementation, the universal vertical emission layer may include a substrate that may include an emission epitaxial stack layer located on any surface of the substrate. The epitaxial stack may include a VCSEL or a PCSEL (or a 2nd order, 3rd order, ..., nth order distributed feedback laser (DFB)). The substrate may include suitable materials such as gallium arsenide (GaAs), gallium nitride (GaN), indium phosphide (InP), silicon (Si), silicon carbide (SiC), etc.

[0146] The lateral contact layer may include a transparent and conductive material. The Pockels material may include a Pockels material such as R42, 63, etc. The metal of the contact may include gold (Au), silver (Ag), copper (Cu) or a transparent conductive material (e.g., such as indium tin oxide (ITO)).

[0147] The EML-based structures 2000 and 2010 may be substantially similar to those described with respect to Fig.19 However, EML-based structures 2000 and 2010 differ from each other (and from EML-based structure 1900) in that there are some variations in the HCG in each of these structures. Specifically, the HCG of EML-based structure 2000 differs from the HCG of EML-based structure 2000 in that the contacts (V1 and V2) in EML-based structure 2000 have different sizes (e.g., V1 is larger than V2, e.g., V1 is larger than V2, e.g., V2 ... Fig. 20 ), whereas these contacts have the same size in the EML-based structure 1900.

[0148] As for the EML-based structure 2010, the HCG used therein is different in that the HCG incorporates a capping layer material (in addition to the undoped semiconductor material) between the contacts, such as Fig. 20. In addition, the EML-based structures 2000 and 2010 differ from the EML-based structure 1900 in that the bias voltages are different (e.g., V1=V2≠V3). However, these two implementations can exhibit similar physical effects as the interdigitated EML-based implementations because the effective refractive index varies differently in each dimer. In this regard, similar effects can be obtained by, for example, filling only about 1 / 2 of the HCG groove with Pockels material, as shown in FIG. Fig. 20 as shown in .

[0149] Fig.21 A sixth exemplary implementation of an interdigital electro-absorption modulated laser (EML) based structure according to the present disclosure is shown.

[0150] refer to Fig.21 , shows an EML-based structure 2100. Specifically, Fig.21 2 shows a top view 2110 of an EML-based structure 2100 and a side view 2120 corresponding to a specific cross section (line) in the structure.

[0151] As shown in the side view 2120, the EML-based structure 2100 includes a universal vertical emission layer, which is followed (in the z direction) by a lateral contact layer (i.e., with a lateral contact layer on top), and then a high contrast grating (HCG), which includes two contacts (V1 and V2), which include semiconductor (e.g., doped semiconductor) material, where the metal is located on top of the Pockels material. The contacts are (optionally) covered by a cap layer (not shown in the top view 2110). A cap material is also provided between the contacts (especially between their Pockels materials), as shown.

[0152] The universal vertical emission layer may include any suitable structure that can be configured to enable vertical laser emission. In an exemplary implementation, the universal vertical emission layer may include a substrate that may include an emission epitaxial stack layer located on any surface. The epitaxial stack may include a VCSEL or a PCSEL (or a 2nd order, 3rd order, ..., nth order distributed feedback laser (DFB)). The substrate may include suitable materials such as gallium arsenide (GaAs), gallium nitride (GaN), indium phosphide (InP), silicon (Si), silicon carbide (SiC), etc.

[0153] The lateral contact layer may include a transparent and conductive material. The Pockels material may include a Pockels material such as R42, 63, etc. The metal of the contact may include gold (Au), silver (Ag), copper (Cu) or a transparent conductive material (e.g., such as indium tin oxide (ITO)).

[0154] Similar to the EML-based structure 1900, the Pockels material used in this implementation may need to have a low refractive index (e.g., IR<2), such as KDP, polymers, etc., and, in some instances, a bias may be applied to the lateral contact layer such that 3 different biases are applied (however, in many instances, the bias applied to the lateral contact layer may be the same as the bias applied to one of the contacts (e.g., V3=V2=0)). In addition, as with the previous implementation, a vertically emitting epitaxial stacked layer located between the substrate and the EML or below the substrate may or may not be included. Although not shown, as with the EML-based structure 1900, alternative implementations may be used by modifying the HCG structure in the same manner as the HCG is modified in the EML-based structures 2000 and 2010 relative to the EML-based structure 1900, such as with respect to Fig. 20 described.

[0155] Fig. 22 An exemplary vertical cavity surface emitting laser (VCSEL) based electro-absorption modulated laser (EML) incorporating a high contrast grating (HCG) having a Pockels material and a dielectric for a gate according to the present disclosure is shown. Fig. 22 , VCSEL 2200 is shown.

[0156] The VCSEL 2200 may include a VCSEL epitaxial layer (without or with a small number of top pairs), wherein a grating (e.g., HCG) structure on top has a Pockels material filling the gaps within the grating structure, and wherein contacts are on top of the surface of the grating structure. Some of the contacts may incorporate a dielectric (for a gate). In this way, some of the contacts (e.g., contacts lacking a dielectric) may be formed and / or operated as a ground, while the remaining contacts (e.g., contacts incorporated with a dielectric) may serve as RF elements in the VCSEL 2200.

[0157] Fig.23 An exemplary vertical cavity surface emitting laser (VCSEL) based optical device is shown, in which an optical device incorporates an electro-absorption modulated laser (EML) based design. Fig.23 2300 and 2310 are shown in FIG. 2 , both of which are VCSEL-based devices. In this aspect, the top view of the optical devices 2300 and 2310 is as shown in FIG. Fig.23 as shown in .

[0158] like Fig.23 As shown in FIG. 2 , the optical device 2300 includes a VCSEL-based structure (e.g., as described with respect to FIG. 2 ) located on top of a substrate etch. Figure 2The optical device 2300 may be configured to respond to the RF in The signal is applied as input to the contact wiring on one end and outputs the corresponding RF out / dump The signal emits light (eg, laser light) as an output at the other end of the contact wiring.

[0159] Optical device 2310 represents an exemplary modification of optical device 2300 according to an exemplary implementation based on the present disclosure. In this aspect, optical device 2310 can be substantially similar to optical device 2300, but can incorporate modifications to allow for providing modulation functionality and / or characteristics thereof as described herein. For example, optical device 2310 can incorporate modifications to contact wiring, such as by using multiple separate contact wirings, such as Fig.23 , to form an interdigital grating-based design that allows the contacts to be biased, as described above, for example, by grounding some of the contact wiring (e.g., applying a ground signal thereto), as shown in FIG. Fig.23 as shown in .

[0160] As used herein, "and / or" refers to any one or more of the items connected by "and / or" in a list. As an example, "x and / or y" means any element in the three-element set {(x), (y), (x, y)}. In other words, "x and / or y" means "one or both of x and y". As another example, "x, y and / or z" refers to any element in the seven-element set {(x), (y), (z), (x, y), (x, z), (y, z), (x, y, z)}. In other words, "x, y and / or z" means "one or more of x, y and z". As used herein, the term "exemplary" means serving as a non-limiting example, instance, or illustration. As used herein, the terms "for example" and "such as" demarcate a list of one or more non-limiting examples, instances, or illustrations.

[0161] As used herein, the terms "circuit" and "circuitry" refer to physical electronic components (e.g., hardware) and any software and / or firmware ("code") that can configure the hardware, be executed by the hardware, or otherwise be associated with the hardware. As used herein, for example, a particular processor and memory (e.g., a volatile or non-volatile memory device, a general-purpose computer-readable medium, etc.) may include a first "circuit" when executing a first line or more lines of code, and may include a second "circuit" when executing a second line or more lines of code. In addition, a circuit may include analog and / or digital circuitry. For example, such circuitry may operate on analog and / or digital signals. It should be understood that a circuit may be in a single device or chip, on a single motherboard, in a single chassis, in multiple housings at a single geographic location, in multiple housings distributed over multiple geographic locations, and the like. Similarly, the term "module" may, for example, refer to physical electronic components (e.g., hardware) and any software and / or firmware ("code") that can configure the hardware, be executed by the hardware, or otherwise be associated with the hardware.

[0162] As utilized herein, a circuit system or module is “operable” to perform a function whenever it includes the necessary hardware and code (if either is necessary) to perform that function, regardless of whether performance of that function is disabled or not enabled (e.g., by user-configurable settings, factory trims, etc.).

[0163] Other embodiments of the present invention may provide a non-transitory computer-readable medium and / or storage medium, and / or a non-transitory machine-readable medium and / or storage medium on which machine code and / or a computer program are stored, the machine code and / or computer program having at least one code segment that can be executed by a machine and / or computer, thereby causing the machine and / or computer to perform the process described herein.

[0164] Various embodiments according to the invention may also be embedded in a computer program product, which includes all the features enabling the implementation of the methods described herein and which, when loaded in a computer system, is capable of carrying out these methods. A computer program in this context refers to any expression of a set of instructions in any language, code or symbol, which is intended to cause a system with information processing capabilities to perform specific functions directly or after one or both of the following: a) conversion into another language, code or symbol; b) reproduction in a different material form.

[0165] Although the present method and / or system has been described with reference to certain implementations, it will be appreciated by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the present method and / or system. In addition, many modifications may be made to adapt specific situations or materials to the teachings of the present disclosure without departing from the scope thereof. Therefore, the present method and / or system is intended not to be limited to the specific implementation disclosed, but rather the present method and / or system will include all implementations falling within the scope of the appended claims.

Claims

1. An optical device, comprising: light source; as well as a modulator, located on the light source, Wherein, the modulator comprises a high contrast grating structure, the high contrast grating structure comprises a plurality of grating lines, and Wherein, the grating lines include Pockels material.

2. The optical device according to claim 1, wherein: At least one grating line of the plurality of grating lines includes a contact.

3. The optical device according to claim 2, wherein: When a voltage is applied to the contacts, the modulator is operable to reflect an optical signal from the light source back to the light source.

4. The optical device according to claim 2, wherein: The modulator is operable to deflect an optical signal received from the light source by a tunable angle from perpendicular to a surface of the modulator based on a voltage applied to the contacts.

5. The optical device according to claim 1, wherein: The plurality of grating lines comprises a sub-wavelength dimension in at least one dimension.

6. The optical device according to claim 1, wherein: The light source includes a vertical cavity surface emitting laser, a photonic crystal surface emitting laser or a high-order distributed feedback laser.

7. The optical device according to claim 1, wherein: The refractive index associated with the modulator is configured by one or more of: the width of the grating lines, the spacing between the grating lines, and the periodicity of the grating lines.

8. The optical device according to claim 7, wherein: The modulator is configured to provide phase modulation to an incident beam or wave coupled into the modulator based on adjustment of the refractive index associated with the modulator.

9. The optical device according to claim 1, wherein: The modulator is configured to provide polarization modulation to an incident beam or wave coupled into the modulator.

10. An optical device comprising: light source; as well as a modulator, located on the light source, Wherein, the modulator comprises: a high contrast grating structure comprising a plurality of grating lines, the plurality of grating lines comprising a first material; and The Pockels material is located between the first materials or on the first material.

11. The optical device according to claim 10, wherein: The first material includes a semiconductor.

12. The optical device according to claim 10, wherein: The first material includes a dielectric material.

13. The optical device according to claim 10, wherein: At least one grating line of the plurality of grating lines includes a contact.

14. The optical device according to claim 13, wherein: When a voltage is applied to the contacts, the modulator is operable to reflect an optical signal from the light source back to the light source.

15. The optical device according to claim 13, wherein: The modulator is operable to deflect an optical signal received from the light source by a tunable angle from perpendicular to a surface of the modulator based on a voltage applied to the contacts.

16. The optical device according to claim 10, wherein: The plurality of grating lines comprises a sub-wavelength dimension in at least one dimension.

17. The optical device according to claim 10, wherein: The light source includes a vertical cavity surface emitting laser, a photonic crystal surface emitting laser or a high-order distributed feedback laser.

18. The optical device according to claim 10, wherein: The refractive index associated with the modulator is configured by one or more of: the width of the grating lines, the spacing between the grating lines, and the periodicity of the grating lines.

19. The optical device according to claim 18, wherein: The modulator is configured to provide phase modulation to an incident beam or wave coupled into the modulator based on adjustment of the refractive index associated with the modulator.

20. The optical device according to claim 10, wherein: The modulator is configured to provide polarization modulation to an incident beam or wave coupled into the modulator.

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