JP2020530666A - High power laser grid structure - Google Patents

Abstract

Various embodiments for laser devices are disclosed herein. In an exemplary embodiment, the laser apparatus is (1) a laser emission epitaxial structure having a front surface and a back surface, the laser emission epitaxial structure is back emission, and a plurality of laser regions are provided in a single mesa structure. A laser emission epitaxial structure in which the laser region has an aperture and a laser beam is radiated in a controllable manner through the aperture, and (2) a microlens array located on the back surface of the laser emission epitaxial structure of the microlens array. A microlens array in which each microlens is aligned with the laser region of the laser emission epitaxial structure, and (3) a non-coherent beam combiner positioned to non-coherently combine multiple laser beams emitted from the aperture. And.

Description

Low-cost, high-efficiency, high-power semiconductor lasers are used in the technical field for directed energy applications, such as illumination lasers, beacon lasers, or for exciting other lasers. is necessary. Surface emitting laser devices can be specifically configured to scale power. Such devices are typically top-emitting or back-emitting, where the entire cavity is created within a series of mirrors and active regions. Other designs would move one side of the finished mirror outward by a relatively long distance of a few millimeters. Designing an external cavity for such a laser device has proven difficult to make in an array configuration, which is due to the non-planar curvature of the chip after bonding. Will adversely affect the mirrors in the internal cavity, optimizing only a small number of arrays at a time, thereby reducing consistent results.

U.S. Patent Application Publication No. 2011/01765667 U.S. Patent Application Publication No. 2017/0033535 U.S. Pat. No. 5,978,408

Yoshikawa et al., "High Power VCSEL Devices for Free Space Communication", Proc. of Electronics Components and Technology Conference, 2005, pp. 1353-58 Vol. 2

As a solution to these problems in the art, we disclose semiconductor laser structures that offer multiple advantages in overcoming curvature. An example of such a structure may be a back-emission epitaxial structure having a plurality of laser regions in a single mesa structure, each laser region having an aperture, through which the laser beam can be controlled. Is radiated to. Each aperture may be part of a laser cavity. Unlike the conventional approach of the art described above where curvature is an issue, the completion of a mirror stage, which is a series of layers that have contrast in the index of refraction of the material, uses a mirror or reflective layer on the wafer. Each cavity is not adversely affected because it is completed. This consistent distance can be used in conjunction with beam-forming optics to optimize output within larger device apertures (but maintain the overall output power of the extended cavity device array). More apertures are used to do this). When using the conventional design, when the chip is bonded to the substrate, the stress causes the chip to deform slightly from a flat surface to a slightly curved surface, positioning a mirror array that is flat with respect to the surface of the chip. Make it impossible to match. The flatness of the cavity is an important alignment feature because it controls the feedback back to the aperture.

When using the exemplary embodiments described herein, the curvature problem experienced by conventional solutions in the art is by using the back surface of the laser substrate as the mounting surface for the microlens array. Can be overcome; this surface is always flat and perpendicular to all laser optic axes for the laser region. This architecture provides a smaller aperture size than conventional designs, but this smaller aperture size can be offset by some laser regions and corresponding apertures that may be included in the semiconductor laser structure. In this case, a non-coherent beam combiner can be positioned to non-coherently couple the laser beams emitted by these apertures with the aim of obtaining a low coherence length for the entire beam, which is illuminated. Useful for equipment and beacon lasers.

Accordingly, according to the exemplary embodiments described herein, the power is increased, but the pulse width is reduced, the size is reduced, the weight is reduced, and the cost is reduced. Design architecture is obtained. Therefore, the technology described herein is high power, with high beam quality, suitable for use as a luminaire or beacon laser that can be used for directed energy weapons for drone defense. It is expected that performance will be improved by obtaining a beam with a short coherence length.

These and other features and advantages of the present invention will be described herein to those of skill in the art.

It is a figure which shows the embodiment of the implant of the exemplary top luminescence. It is a figure which shows the embodiment of the implant of the exemplary top luminescence. It is a figure which shows the embodiment of the implant of the exemplary top luminescence. It is a figure which shows the embodiment of the implant of the exemplary top luminescence. It is a figure which shows the embodiment of the implant of the exemplary top luminescence. It is a figure which shows the embodiment of the implant of the exemplary bottom emission (bottom emtiting). It is a figure which shows the embodiment of the oxidation of the top emission of an example. It is a figure which shows the embodiment of the oxidation of the top emission of an example. It is a figure which shows the embodiment of the oxidation of the top emission of an example. It is a figure which shows the embodiment of the oxidation of the top emission of an example. It is a figure which shows the embodiment of the oxidation of the top emission of an example. It is a figure which shows the embodiment of the oxidation of the bottom light emission of an example. It is a figure which shows the embodiment of the oxidation of the bottom light emission of an example. It is a figure which shows the embodiment of the oxidation of the bottom light emission of an example. It is a figure which shows the embodiment of the oxidation of the bottom light emission of an example. It is a figure which shows the embodiment of the oxidation of the bottom light emission of an example. It is a figure which shows the embodiment of the oxidation of the bottom light emission of an example. It is a figure which shows the embodiment of the oxidation of the bottom light emission of an example. It is a figure which shows the embodiment of the oxidation of the bottom light emission of an example. It is a figure which shows the embodiment of the oxidation of the bottom light emission of an example. It is a figure which shows the embodiment of the oxidation of the bottom light emission of an example. It is a figure which shows the embodiment of the oxidation of the bottom light emission of an example. It is a figure which shows the embodiment of the oxidation of the bottom light emission of an example. It is a figure which shows the embodiment of an exemplary microstrip. It is a figure which shows the embodiment of the exemplary phase coherent. It is a figure which shows the example embodiment which adopts a diffractive optical element. It is a figure which shows the example embodiment which adopts the pattern diffraction grating (pattern diffraction grating). It is a figure which shows the embodiment of an exemplary microlens. It is a figure which shows the tenth embodiment of an exemplary. It is a figure which shows the eleventh embodiment of an example. It is a figure which shows the twelfth embodiment of an exemplary. It is a figure which shows the example of the additional pattern for a lasing grid which is related to various embodiments. FIG. 5 shows a comparison of current flow between an exemplary embodiment designed as described herein and an embodiment taught by US Patent Application Publication No. 2011/01765667. It is sectional drawing which shows the laser apparatus by an exemplary embodiment. FIG. 6 is a cross-sectional view showing an exemplary extended cavity showing a lens located on the back side of a laser wafer, where the lens has a dielectric coating that acts as a mirror. It is a figure which shows the simulation result for an exemplary embodiment. FIG. 5 illustrates an exemplary flexible beam coupling technique that can be used with an exemplary embodiment of a laser device. FIG. 28 is a perspective view showing the flexible beam coupling technique of FIG. It is sectional drawing which shows the exemplary laser apparatus which has a laser structure in combination with a graphene lens structure. FIG. 5 illustrates an exemplary process that can be used to form a graphene lens structure. FIG. 5 illustrates an example in which the graphene lens structure can be designed to vary with respect to width and spacing. FIG. 5 discloses an exemplary graphene lens design that can replace the lens formed in an extended cavity design for a laser structure. It is a figure which shows the example graphene lens design which can replace a diffractive optical element (DOE) in a laser structure.

FIG. 25 shows a cross-sectional view of an exemplary laser device 2500 including a laser structure 2502 in combination with a microlens array 2504 and a non-coherent beam combiner 2510. The laser structure 2502 may be a laser emission epitaxial structure having a front surface (top) 2504 and a back surface 2506, and the laser emission epitaxial structure is back emission. The laser structure includes a plurality of laser regions in a single mesa structure, each laser region has an aperture, and a laser beam is radiated in a controllable manner through this aperture. As shown by FIG. 25, the microlens array 2502 is placed on the back surface 2506 of the laser structure 2502. Each microlens of the microlens array 2504 is aligned with respect to the laser region of the laser emission epitaxial structure 2502. The non-coherent beam combiner 2510 is positioned to non-coherently combine multiple laser beams emitted from the aperture.

An example of a device that can be used as a laser structure 2502 is disclosed and described in US Patent Application Publication No. 2017/0033535 below, the disclosure of which is incorporated herein by reference in its entirety and a copy thereof. Included as Appendix A. Appendix A describes a laser structure formed from a plurality of conductive grids, and in an exemplary embodiment, the laser structure formed from the plurality of conductive grids is a single semiconductor laser in the mesa structure. Units and their connections to high speed electrical waveguides for high frequency operation can be embodied. Additional examples of devices that can be used as the laser structure 2502 are disclosed and described in the following US patent application, each disclosure of which is incorporated herein by reference in its entirety: (1) 2017 2 US Patent Application No. 62 / 456,476, (2) filed February 2, 2017, entitled "Methods to Advance Light Grid Resources for Low-Cost Laser Sources", filed on February 2, 2017. Also, U.S. Patent Application No. 62 / 456,489, entitled "Fabrication of Light Grid Structures with Before Scale Processing," (3) "High Power Force Road," filed on February 2, 2017. U.S. Patent Application No. 62 / 456,501, entitled "Applications over Distance," (4) A U.S. Patent Application, entitled "Methods for Advanceing High Brightness Directions," filed February 2, 2017. No. 62 / 456,518, and (5) "Ridging Radi Structure Array Configured to Scan, Communicated, and Process Material Usage Defense," filed on February 15, 2017, U.S. Pat. Application No. 62 / 459,061.

Further, the laser structure 2502 can also be configured as an array of multiple laser emission epitaxial structures, where each laser emission epitaxial structure has a single mesa structure, where the single mesa structure is a plurality of separated laser regions. including. In such an array, the laser structure 2502 can include a plurality of mesa structures, each mesa structure including a plurality of separated laser regions. Such a laser grid structure can exhibit several laser emitters on a small chip.

As an exemplary embodiment, a laser device 2500 may be used within a beacon illuminator laser. In this technology, the laser cavity may extend to the back of the wafer, as shown in FIG. 26, with the aim of eliminating external alignment of the optical components. This design approach can dramatically improve beam quality (M ² <1.5). Moreover, in a non-coherent beam forming architecture, the coherence length of a beam can be reduced to less than 1 mm by using multiple low coherence beams with high quality beam characteristics defined by the characteristics of the individual beams. ..

The method of combining the laser structure 2502 with the microlens array 2504 involves 2D photolithography techniques, which allows tens of thousands of chips to be deployed on a single 4 ”wafer (FIG. 26). Referring to the substrate 2600), further examples of. extended cavity device eliminates the complexity of the chip scale achieved M ² value <1.5. in practice, this wafer-level process, the output power and It would eliminate thousands of hours of alignment adjustments within a single wafer in a single process while improving reliability.

As shown in FIG. 26, the microlens array can include a plurality of curved lenses 2610, each curved lens 2610 having a smooth radius of curvature. The lens array can be etched to the back surface of the laser substrate on the opposite side of the back emission epitaxial growth side. First, patterning is performed using a thin photoresist, and the photoresist is heated so as to exceed the glass transition state, which is the timing at which the glass melts, and the photoresist melts to form a lens-type structure due to surface tension. At that time, the lens array is etched. In this way, this lens-shaped structure can serve as a mask for etching this structure onto the surface of the GaAs laser wafer. The radius of curvature of the lens (ROC: Radius of Curvature) can be controlled by adjusting the selectivity between BCl3 and Cl, including the removal of GaAs, as compared to the resist removal rate. This can be achieved by adding O2 to the plasma or by other methods. Graphene lenses can also be replaced with etched lenses in creating an array of lenses on the back of the chip, as will be discussed later, or if graphene lenses are used as beam forming arrays, graphene. The lens may be formed as a microlens array on an external clear or transparent substrate.

Each lens 2610 may be aligned on the back surface 2506 of the substrate 2600 with a laser cavity 2602 in the substrate 2600 that terminates at the aperture. For ease of explanation, only one such cavity 2602 is shown in FIG. 26, but it should be understood that each of the lenses 2610 can be aligned with a variety of laser cavities 2602. Each cavity 2602 exhibits an optical axis that coincides with the direction of beam emission through the aperture (eg, the vertical axis when relative to the configuration of FIG. 26).

The lens 2610 may be covered with a reflective coating, such as a reflective dielectric, so that the lens 2610 acts as a mirror for some of the light emitted from the laser cavity 2602. As shown by FIG. 26, the lens 2610 is curved to provide a feedback mechanism that concentrates the light towards the center of the cavity 2602 for the purpose of improving beam quality and beam output. Good. Thus, this reflected light is further directed into the cavity 2602, creating a greater concentration of light energy of the beam radiation along the central optical axis of the cavity 2602. By lengthening the cavity 2602, stabilization can be achieved and better quality beam output can be achieved.

The degradation in beam quality that results from laser feedback to the cavity 2602 can be mitigated by adapting the cavity 2602 to the radius of curvature of the accurately modeled microlens. If the feedback spot is optimized to fit this area to the current confinement area of the laser, avoid overfilling or underfilling the active area of the laser where the current produces photons. Allows the power out to be optimized. Epitaxy design also requires further growth execution to optimize reflectance in epitaxial power mirrors. The output power depends on the reflectance of the output mirror. As the mirror reflects more, the number of photons that go out decreases and the number of photons that reflect back into the cavity increases. Adjusting the reflectance of the output cavity helps optimize the power out. The reflectance can be adjusted by modifying the epitaxial layer or by adjusting the finished layer of the mirror where the microlens is deposited on the surface of the etched array.

Examples of wafer-scale photolithography techniques that can be used to make these lenses 2610 are described below with reference to FIGS. 30-34. When using such wafer-scale photolithography, hundreds of thousands of lenses can be simultaneously aligned and formed.

Compared to beams from coherent arrays, beams from non-coherent arrays, as shown by FIGS. 25 and 26, have shorter coherence lengths and create less speckle on the target. It is believed that the coherence length for the arrays of FIGS. 25 and 26 can be less than 1 mm. All low coherence arrays tested showed a linear relationship with powerout when the laser was added. 100 lasers, each with an output of 1 mW, will generate 100 mW of power, and 1 million lasers, each of 0.1 W, will generate 100,000 watts of optical power. .. Coherent structures have more scintillation in the far field. FIG. 27 shows the results of a simulation using a wave-optics beam propagator for the exemplary embodiment of FIG. The tophat beam of the hexagonal array is propagated through one embodiment of the turbulence in the case of having mutual coherence and in the absence of mutual coherence. White circles in each target irradiation frame indicate target spots. As mentioned above, a non-coherent array is simulated as producing less speckle on the target spot.

The configuration of FIGS. 25-26 further allows for a new kind of beam coupling. In an exemplary embodiment, the non-coherent beam combiner 2510 can take the form of additional lens elements such as a microlens external to the laser structure 2502 and the microlens array 2504. The beam points forward out of the Microlens Arrays 2504, the beam combiner 2510 behaves to bend at the edge of the beam, and all beams are focused due to the difference in the offset of the laser pitch to the lens pitch. To do. Therefore, the beam combiner 2510 guides the beam towards a single spot in front of the 2D array. The non-coherent beam combiner 2510 can employ 2D beam coupling such that it has overlapping focusing points. However, it should be understood that the beam combiner 2510 can also employ 3D beam coupling with multiple overlapping focusing points.

FIG. 28 shows an exemplary flexible beam coupling technique that can be used with an exemplary embodiment of the laser apparatus 2500. In FIG. 28, the bottom layer in the array stack may be a complete laser grid array, whereas the top layer in the stack is an opening in the laser grid array (eg, a central hole as shown by FIG. 28). ) Can be included. The microlens array 2504 in the upper stack can employ a torus-shaped lens. A series of these torus-shaped lenses on the series of laser grid arrays of FIG. 26 are arranged in a Z-axis having vertices equal to any cone of light generated by the torus-shaped lenses. These cones pass through the torus lens in front of the lens without interference from the lens. Each system of torus lens and optical grid can be assembled to have multiple cones that generate large powers on equal spots or at the vertices of all cones. FIG. 29 shows a perspective view of the beam coupling shown by FIG. 28.

Therefore, FIGS. 25-29 illustrates an exemplary embodiment for an optical grid structure capable of exhibiting high speed (on / off speeds greater than 1 GHz) and high power output from a VCSEL semiconductor laser array. ing. This optical grid structure facilitates higher yields due to the constructive array design discussed herein. The device uses a simplified manufacturing design process, thereby achieving improved speed and power performance with a fully semiconductor laser chip that uses a wafer-scale process, thereby performing complex assembly tasks. Exclude. This allows for miniaturization, cost savings, and increased beam characteristic flexibility by using this manufacturing process instead of aligning with costly and complex external microlens / mirror arrays. To. Therefore, the technology aims to improve the automated production of high beam quality, high power, short coherence length semiconductor laser arrays that can be used in applications such as directed energy weapons for drone defense. Become.

FIG. 30 shows a cross-sectional view of an exemplary laser device 2500, where the microlens array takes the form of a graphene lens structure 3000. The graphene lens structure 3000 may be a single graphene lens structure or an array of graphene lens structures.

FIG. 31 discloses an exemplary process that can be used to form the graphene lens structure 3000. In step 3100, graphene is deposited on the back surface 2506 of the laser structure 2502 (eg, a laser structure formed from a plurality of back emitting conductive grids, such as those described later in Appendix A). At step 3102, photolithography is used to mask the area of deposited graphene. These masked areas will not be plasma etched. FIG. 32-34 shows an example of a mask pattern that can be used as this step. The graphene lens structure 3000 is then formed in step 3104 by plasma etching the deposited graphene so that the masked area is not plasma etched. As an example, O2 plasma etching can be performed. This provides a photolithographic lens structure that can be used as the graphene lens structure 3000 within the device 2500. This innovative process is an inherent high contrast reflection between two materials that are semiconductors such as graphene and GaAS to index guide or guide the light formed by the laser structure 2500. Use the rate difference.

FIG. 32 shows an example in which the graphene lens structure 3200 can be designed to vary in width and spacing. In this example, the graphene lens structure 3200 comprises a plurality of concentric graphene rings 3202. The width of the graphene ring 3202 and the spacing between the graphene rings 3202 can be controlled and defined during the masking process to achieve the desired optical effect for the graphene lens structure 3200. In addition, the example in FIG. 32 shows an exemplary 4x4 matrix mask for a unique array of 16 lenses, where the two masks are light field and dark field. Can be adopted for field).

FIG. 33 shows an exemplary graphene lens design that can replace the formed lens in the extended cavity design for the laser structure 2500. The upper part of FIG. 33 shows different examples of width and spacing characteristics that can be used for this graphene lens structure, and the lower part of FIG. 33 shows an exemplary VCSEL laser structure corresponding to FIG. 21 of Appendix A. Shown. This graphene lens structure can replace the formed lens described in Appendix A in connection with FIG. 21 for the purpose of improving the design. In addition, a reflective coating can be deposited on the surface of the graphene lens structure.

FIG. 34 shows an exemplary graphene lens design that can replace the diffractive optics (DOE) in the laser structure 2500. The upper portion of FIG. 34 shows different examples of width and spacing characteristics that may be used for the graphene lens structure, and the lower portion of FIG. 34 shows an exemplary laser structure corresponding to FIG. 18 of Appendix A. (Incorporated as referenced above, U.S. Patent Application No. 62 / 456,476, U.S. Patent Application No. 62 / 456,489, U.S. Patent Application No. 62 / 456,501, U.S. Patent Application No. 62 / See also 456,518, and U.S. Patent Application No. 62 / 459,061). The graphene lens structure can replace the DOE described in various embodiments of Appendix A for the purpose of improving the design. As shown by FIG. 34, a graphene lens structure can be used with the laser structure for the purpose of directing the laser light in a manner that makes the laser light appear to originate from a single source.

Although the present invention has been described above in relation to the exemplary embodiments, various modifications to the exemplary embodiments that are recognized by those skilled in the art and still within the scope of the invention have been made. Can be Such modifications to the present invention can be recognized by scrutinizing the teachings herein. Therefore, the entire scope of the present invention is defined only by the appended claims and their legal equivalents.

Appendix A-US Patent Application Publication No. 2017/0033535 Laser arrays are compared to single lasers, fiber lasers, diode pumped solid state (DPSS) lasers, and light emitting diodes (LEDs). Therefore, it is becoming important in the fields of communication, light detection and ranking (LiDaR), and material processing because of its high operational optical power and high frequency operation.

Laser arrays, commonly used in printing and communication, are used in configurations that have a single, separate connection to each laser device in the array for parallel communication. , Each laser can have a separate signal because it has a separate contact with the other devices in the array.

When the array elements are integrally coupled and driven by a single signal, the structure will have too much capacitance or inductance. This high capacitance / high inductance characteristic will slow down the frequency response of the laser array as the laser array adds more elements, thereby slowing down such a laser array. .. This is described in "High Power VCSEL Devices for Free Space Optical Communications" by Yoshikawa et al., Proc. of Electronics Components and Technology Conference, 2005, pp. 1353-58 Vol. 2. And US Pat. No. 5,978,408, which is specified in the references.

High-speed laser arrays based on multimesa structures are described in the inventor's previous literature, US Patent Application Publication No. 2011/01765667. U.S. Patent Application Publication No. 2011/01765667 describes multimesa arrays of semiconductor lasers and their connections to high speed electrical waveguides for high frequency operation. However, the multimesa structure described in US Patent Application Publication No. 2011/01765667 has many drawbacks.

One problem with the mesa structure described in US Patent Application Publication No. 2011/01765667 is that the mesa structure is generally fragile. This is a problem if there are any mechanical procedures for bonding or touching the laser after the formation of the mesa. The mesa structure can be as small as 5 to 10 microns in diameter and can be composed of very brittle materials such as GaAs or AlGas or other similar crystalline materials. These mesas must be glued after processing and pressure is applied under heat so that the top and submount of the laser mesas are electrically glued together by solder. A common breaking mechanism at the junction when gluing an array of back-emitting device is to crack the mesa, which makes the laser useless and can dispose of the entire device. If there are 30 lasers on the chip and the two lasers break after bonding, these two devices will not emit light. Further testing must be done, which makes the process for eliminating failures expensive.

Another problem is that the multi-mesa structure makes the lasing power relatively small depending on the chip real estate due to the spacing requirement for multiple mesas present on the laser chip. ..

Another problem with multiple mesa arrays created by the mesa separation method is that the laser separates at a distance due to frequency response dependent design parameters that prefer a shorter distance for the signal to travel across the contact pad. This limits the overall size of the array. This was followed by the array being used with power-enhancing elements such as multiple Vertical Cavity Surface Emitting Laser (VCSEL) arrays used for infrared (IR) irradiation. .. However, since these IR sources do not support high frequency operation, the pulse width is limited to illumination only, not lidar, which requires high pulse width.

To meet the demands of the art in the case of laser arrays that are stronger, more powerful and faster, we disclose some embodiments of the invention herein. For example, an embodiment of the present invention described below aims to integrally connect array lasers while reducing capacitance by forming a signal pad that employs an electrical waveguide on a substrate. Incorporate a high frequency electrical waveguide. Embodiments of the present invention further include using a multi-conductive current confinement technique within a single structure to create multiple areas that are conductive as opposed to non-conductive parts of the structure. .. The conductive portion forms a lasing area or lasing grid that forms the laser without etching over the entire structure of the lasing point. Unlike the design described in US Pat. No. 5,978,408 referenced above, embodiments of the invention disclosed herein make the laser array fast electrical to enable high frequency operation. Designed and machined to integrate with the waveguide. Embodiments of the present invention support new and unique opportunities in the design of high-power, high-speed light sources by exhibiting both high-frequency operation and rigid structures, thereby being known in the art. Improves performance and reliability compared to other designs.

In the exemplary embodiments described herein, a unique structure machined from an epitaxial material of a vertical cavity surface emitting laser (VCSEL), such as the structure referred to in US Patent Application Publication No. 2011/01765667. A single rigid body that contributes to high-speed operation by reducing capacitance, improving structural integrity, and reducing fill factors compared to typical mesa structures formed within VCSEL arrays. A grid of laser points is formed from the structure. A VCSEL embodiment is merely an example, such a design as a Resonant Cavity Light Emitting Diode (RCLED), LED, or Vertical Extension Resonator (or Vertical External Resonator) Surface Emitting Laser (VECSEL). : It should be understood that it can work with other laser types such as Vertical Extended (or External) Cavity Surface Emitting Laser).

The single continuous structure described herein uses an ionic implant to form an electrically insulated area of the aperture while maintaining the structural integrity of the material as it is typically etched and removed. Or form a non-conductive oxidation area through the microstructure or pores. The formation of this new structure also allows the high speed signal to be distributed between different separated laser conduction points or grids. All of the P-shaped contact areas of the laser grid can be connected in parallel to the signal portion of the ground-signal-ground (GSG) integrated electrical waveguide. A signal or current that is switched on and off in the waveguide is distributed among all the conductive paths that form the laser. It should be understood that other types of electrical waveguides, such as microstrip waveguides, may be used.

This single continuous structure also has other advantages, such as a larger base for heat distribution within a larger plating structure. The lasing grids are closer to each other than the array structure. As the laser moves further away, the frequency response or speed slows down due to the distance the signal must travel to every single point in the array, which limits the final bandwidth of the device. ..

Therefore, examples of the benefits obtained by embodiments of the present invention are:
1. 1. Rigid structure has higher reliability in chip bonding process 2. Rigid structure allows for higher fill factor 3. 4. Rigid structure has more reliable metal contacts. 4. Rigid structure is simpler in processing. The rigid structure has a shorter distance between the contacts, thereby allowing a higher frequency high power beam. The rigid structure is a better surface topology for mounting a single lens or a single lens array. The rigid mesa structure creates a separate area for leads and contacts, thereby providing isolation from capacitance that lowers the potential. The rigid structure includes the three-dimensionality of the contacts, which allows for greater integrity with the submount.

Further, in an exemplary embodiment, the laser grid can be made possible by confining the current only in isolated areas within the structure where there is conductivity compared to the area where the non-conductive ions are implanted. It is formed by two or more lasing areas. These conductive and non-conductive areas form a single metal contact for active positive contacts on a single solid structure and a single N-shaped contact on the surrounding ground structure. A single N-shaped contact is short-circuited to the N-shaped contact area at the bottom of the trench that separates the two areas, forming a grid of light to have. As an example, FIG. 7C shows how an opening in the frame assists in increasing speed.

These P-type and N-type contacts are then glued to the high speed electrical contacts. The two substrates and the laser chip are aligned by a bonder, and then heat and pressure are applied to bond the solder deposited on one chip or the other chip. Higher speeds are possible by separating the p-type pad from the n-type wafer ground by the amount of plating and solder height, which mainly removes the p-type pad from the laser substrate and conducts the p-type pad electrically. This is due to the installation on the waveguide substrate. Thus physical separation dramatically reduces capacitance, thereby increasing the frequency response limited by the capacitance of the circuit. This allows the lasing grid to achieve high frequency operation.

A single lens formed on the back surface of the substrate, or a single lens attached to or glued to the back surface of the grid structure, can guide each lasing point to or from the focusing point. This is an ideal form for collimating the beam output as if it were from a single source.

These and other features and advantages of the present invention will be described herein to those of skill in the art.

US Patent Application Publication No. 2017/0033535 Embodiment 1-Top luminescent implant FIG. 1 shows an example of a first embodiment of the present invention. In this example, a single solid structure is separated from the surrounding ground using etching, and the single solid structure has an ionic implant in it. Ion implants create areas of non-conductive semiconductor material, and these non-conductive areas carry current through the lasing area 2. In this way, the ion implants formed a laser grid of multiple lasing areas 2, where current was confined in the separated regions within the structure, where non-conductive ions were implanted. There is conductivity compared to the area. Conductive and non-conductive areas are on a single solid structure for active positive (P-type) contacts and for a single negative (N-type) contact on the surrounding ground structure. A single negative (N-shaped) contact forms a grid of light with a single metal contact in the N contact area at the bottom of the trench that separates the two areas or is negative on the surrounding ground structure. Shorted to a metal, this negative metal on the surrounding ground structure is shorted to an N-shaped contact area at the bottom of the trench that separates the two areas (eg, as in FIG. 7C (reference numerals 781 and 782). Please refer to)). These P-type and N-type contacts are further bonded to high speed electrical contacts, which allows the lasing grid to achieve high frequency operation.

Although FIG. 1 shows the lasing area 2 arranged in the grid pattern, it should be understood that lasing areas 2 of many shapes and many patterns can be formed. This allows for many forms of structure having the shape / pattern of the lasing area 2, eg, one of many patterns that allow for a honeycomb structure pattern (eg, a variety of laser shapes or laser patterns). , See FIG. 23 showing another pattern; used for etching and implanting to leave the conductive area 41 for the laser in a single mesa structure relative to the non-conductive area 42. There are many patterns to obtain), and other structural patterns that have higher rigidity while improving adhesion. In addition, a material with a high thermal conductivity material is used in the holes etched into a single mesa structure (see, eg, hole 7005 in FIG. 7) for the purpose of creating multiple lasers closer to the junction. Heat removal can be achieved by depositing. Examples of additional structural patterns may include square or circle-like configurations on a straight line.

FIG. 1 shows a top view of the epitaxial side of the laser chip. A single laser emitting epitaxial structure 1 has an ion-implanted area other than the lasing area 2 (shown as a disk in FIG. 1), and the ion implant masks the ion-implanted area. Has been done. Therefore, FIG. 1 shows the insert after injection and after etching. In contrast to the conventional design of US Patent Application Publication No. 2011/0176567, which has multiple mesas such that each mesa corresponds to a single lasing area, the design of FIG. 1 has multiple mesas. It shows a single continuous structure 1 which does not have, and may instead be characterized by being a single mesa, where the single mesa has a plurality of lasing regions 2. The figure in FIG. 1 is intended to show a single mesa structure rather than an electrical contact. This structure 1 may be bottom emission or top emission depending on the design and reflectance on the N-type mirror as compared with the P-type mirror.

Figure 1 is:
1 Single active mesa structure that will create multiple lasing points 2 Area where the implant is masked so that the implant does not affect the epitaxial area under the mask 3 Single active mesa structure and single Etched separation trench separating one ground structure 4 Shows a single ground structure.

FIG. 2 is a cross-sectional view of the laser chip shown in FIG. 1, in which the single active mesa structure 1 shown in FIG. 1 is attached with 11 and is masked in FIG. 2 as shown by FIG. Implant area 2 is labeled with 12. FIG. 2 shows the tip after implant and etching, not the top metal. The etching region 13 separates the single mesa structure 12 from the "frame" or N-type mesa 14 (in FIG. 2, the single ground structure 4 from FIG. 1 is shown as the frame / N-type mesa 14). .. Figure 2 is:
11 Implanted area of single active mesa structure that separates multiple etching points 12 Area of epitaxy masked from the implant that will produce lasing 13 Single active mesa structure 11 and single ground structure 14 Etched Separation Trench 14 Single ground structure 15 Quantum well between the P-shaped mirror at the top and the N-shaped mirror at the bottom (this is the active region where photons are emitted)
16 Shows an N-type mirror 17 laser substrate with an N-type contact layer, or a high concentration doping layer for the location of N-type metal electrical contacts.

FIG. 3 is a perspective view of the chip shown by FIGS. 1 and 2. The implanted area is invisible. Metal contacts are not shown. This figure is to show the etching topology of a single mesa that can be used for top luminescent or bottom luminescent implant devices (implanted devices). The implant process may be performed before or after the apical metal or etching.

FIG. 4 shows a top view of the epitaxial side of the example top emitting VCSEL grid structure. This figure is through a square hole in the top side electrical waveguide that is bonded to the laser chip by the soldering process. In this figure, the separated etching regions are hidden by an electric waveguide. The circular disc in this figure is a hole in the top metal contact on top of a single solid mesa structure or in the plated metal contact area. Figure 4 is:
41 Hole in the substrate with a waveguide underneath 42 Hole in the P-metal on the top side through which the laser beam can be radiated 43 Top of the waveguide board 44 On the laser chip Shows the top-side waveguide in.

FIG. 5 shows a cross-sectional view of the bonded electrical waveguide and laser chip shown in FIG. A signal contact for the electrical waveguide is opened, allowing the beam to propagate through the opening. Another option of this embodiment is to have a transparent or permeable substrate material for the waveguide instead of the holes, through which the laser is propagated. A transparent material such as diamond or sapphire or glass that is CVD (Chemical Vapor Deposition) can be an example of this material. This figure shows an embodiment using a substrate such as AlNi, which is opaque and therefore requires holes or openings. Note that the isolation region separates a single mesa structure from a single mesa ground or structure that is shorted to ground, or from a "frame" structure.

These P-type and N-type contacts are adhered to high-speed electrical contacts (see also reference numerals 751 to 754 in FIG. 7B). The ground-signal-ground (GSG) electrical waveguide substrate and laser chip are aligned (see Figure 14B) so that the negative mesa is glued to the negative part of the waveguide and emits a laser in the positive active area. Is aligned with the signal pad. This alignment is defined by a bonder and then heat and pressure are applied to bond the solder deposited on one chip or the other chip (see Figure 15). The high speed property of this contact is due to the p-type pad being separated from the n-type wafer ground by the amount of plating and solder height, which is primarily due to its removal from the laser substrate. This is due to the installation on the electric waveguide. Thus physical separation dramatically reduces the capacitance, thereby increasing the frequency response (frequency response is limited by the capacitance of the circuit), providing high frequency operation for the lasing grid. Bring.

In an exemplary embodiment, for high speed operation, a surface is connected to an electrical contact at the bottom of the epi design, which encloses a single structure (eg, see FIG. 7A (reference numeral 717)) and a separation trench (eg, reference numeral 717). , See reference numeral 702 in FIG. 7A). This structure is not based on mesa topology and is simply short-circuited to the electrical region of the N-type contact metal through metal plating (such as reference numeral 782 in FIG. 7C) (see FIG. 7A (reference numeral 703)). .. It uses a chip surface and an epi-material that serves as a surface for adhesion, rather than a stacked or raised structure as described in US Patent Application Publication No. 2011/01765667. In addition, the device is made more stable and firm at the glued part.

Referring again to FIG. 5, the GSG signal pad 51 has a solder 52 that electrically connects the P-type contact metal to the top of the active single mesa structure. This allows signals or currents to be injected into metal contact structures with holes for laser propagation in them, allowing current to flow through the non-implanted regions of the epitaxial structure, thereby defining these. The current is confined only in the area where it is. The P-shaped mirror region at the top has a slightly lower reflectance than the N-type mirror at the bottom, which allows light to be emitted from the top of the epitaxial structure. An electric current flows over the quantum well to generate light and heat in these junctions and enters the n-type mirror, where the electric current is in or near the n-type mirror. Advance to the N-type contact area at. The current then advances towards a shorted frame structure that is adhered to and in electrical contact with the ground portion of the GSG electrical waveguide. This structure, which uses a top emission design, can be used for low wavelength output designs such as below the wavelength of transmission blocking by GaAs or laser substrate materials. Back emission structures are usually designed only for wavelengths above ~ 905 nm. This top light emitting structure can be used at ~ 850 nm or less in the range up to the limit value of the epitaxial material to be installed.

A single solid structure is separated from the surrounding ground using etching, where the single solid structure has an ionic implant within it. The implant is invisible, but makes the semiconductor material non-conductive because of the crystal damage it causes. To make an implant device, you must first mask the area that should be protected from damage.

Small mesas are formed with the photoresist positioned by the photolithographic process, which protects the epitaxial material from damage and is washed off after implanting. The implant is performed in an ion implant machine, which accelerates the ions along the tube and places the wafer in front of the ion stream.

Implanted ions can create areas of non-conductive semiconductor material. These areas of the non-conductive material will be forced into current through the lasing area. These non-conductive areas are also created by etching a pattern similar to that in FIG. 1 and oxidizing this single structure as described later in connection with Embodiment 2. Figure 5 shows:
50 Non-conductive electric waveguide substrate 51 Signal metal of electric waveguide 52 Solder metal for adhering electric waveguide to laser chip 53 Signal pad of GSG electric waveguide shorted to P-type contact layer Electrically connected to a plated metal 54 P-type output mirror-diffractive waveguide.
55 Active region-Quantum well 56 N-type mirror where the low resistance contact layer is placed 57 Plated metal short-circuited or electrically contacted with the N-type contact layer and ground mesa 58 Electricity to the ground pad of a high-speed electric waveguide Plated metal connected to a P-metal on a single mesa structure for contacting a signal pad on a solder 59 high speed electrical waveguide, which is in contact and is in electrical contact with the grounded mesa structure. Shows the upper area.

FIG. 24 shows a comparison of different current flows between embodiments such as Embodiment 1 and the design taught by US Patent Application Publication No. 2011/01765667. In US Patent Application Publication No. 2011/01765667, each mesa is surrounded by an N-shaped metal contact area. Valuable space or area on the chip is used for this, because the process for defining these stepped metal n-type contacts around each mesa requires photolithography, which This is because it limits how close the distance between mesas can be. These restrictions result in lower power output per unit area compared to the new method. Therefore, although the purpose of this old device was an array for very high power and speed, it did not consider making significant improvements in power / area, and large improvements in power / area are very high. It is also an improvement in the ultimate goal of gaining very much power in speed. Also, the N-type contacts of this old method need to be large because of the structural constraints of the old method that were eliminated when using the new single structure.

When using the new design described herein, a single structure has multiple layers on top of it, with only one contact around this single structure. This new structure reduces the N-type metal area to the outside of the structure and significantly reduces the area of each optical element. It involves a large N-type contact layer that is calculated to carry a single structure current load. Increasing current flow from a single contact can be achieved through thicker metal or thicker N-type contact regions.

US Patent Application Publication No. 2017/0033535 Embodiment 2-Bottom Luminous Implant FIG. 6 shows a cross-sectional view of an example of a second embodiment, wherein the second embodiment is current confined. It is a bottom luminescent device with an implanted area for. The GSG electrical waveguide can be seen soldered to the frame-ground structure and to the active single laser mesa structure. Figure 6 shows:
601 Electric waveguide substrate 602 Ground contact and signal contact in the order of GSG electric waveguide 603 Solder-bonded part of GSG waveguide to laser chip 604 Signal pad of electric waveguide is P type of laser Plated metal 605 P-type contact metal that electrically connects to contacts 606 Implanted region in a non-conductive state 607 P-type mirror 608 Active region (quantum well)
609 N-type mirror 610 Conductive layer in the N-type mirror where the implant cannot reach 611 Laser beam propagating through the laser substrate 612 Plating metal short-circuited to the N-type contact area 613 Frame area short-circuited to the N-type contact area 614 Solder that electrically connects an N-type contact on a laser to the ground on an electrical waveguide 615 Shows an etching region that separates a large single mesa from the ground frame.

Process for Embodiments 1 and 2 of U.S. Patent Application Publication No. 2017/0033535 Illustrative process steps for creating a single structure for Embodiments 1 and 2 using implant current confinement. Embodiments of may be described as follows.

Step 1. Photolithography is used to mask areas where P-metals are not deposited.

Step 2. A P-type metal (usually ~ 2000A TiptAu) is deposited.

Step 3. Photolithography-lift-off and wafer cleaning. Ashing of all organic matter from O2 discum or wafer.

Step 4. A dielectric deposit (usually ~ <1000A SiNx) is used as the etching mask.

Step 5. Photolithographic masking using photoresists or metals deposited in multiple areas to protect epimaterials from damage from implants that make non-protected areas non-conductive through ionic impact. This step may be performed later in the process, but it can be more difficult to perform due to the larger changes in topology.

Step 6. Implants (technical artisans who calculate implant doses determine the amount and dose of implants needed to separate the material structure to a depth that would separate the p-type region and quantum well from each other. Will be).

Step 7. Due to the implant, it is difficult to clean this photolithography and it can help facilitate metal deposits such as plating on the photolithography to wash off the resist.

Step 8. Photolithography is used to mask the unetched dielectric area. This is a unique part of the mask design that creates a large structure that is separated below the implant within this structure that defines where no current can flow.

Step 9. Plasma etching can be used to perform etching through the dielectric (usually a Fl-based etching agent), or wet etching such as BOE (buffered oxide etch) (buffered oxide etching) can be used.

Step 10. Etch the pattern into the epitaxial material of the laser or light emitting diode. Stop on the substrate or doped electrical contact layer. This separates a single large structure from the N-type short circuit region around the chip.

Step 11. Wash off the mask. Ashing of all organic matter from O2 discum or wafer.

Step 12. Photolithography is used to mask areas where N-metals are not deposited.

Step 13. An N-type metal (usually a GeAu / Ni / Au eutectic composition having an atomic weight of 80% Au / 20% Ge) is deposited. An AuGe layer having an overall thickness of ~ 3000 A or more, having Ni of ~ 200 A or more as another diffusion barrier metal and Au of ~ 5000 A or more. It is also due to the fact that the n-type metal is deposited in the n-type contact etching region and is also deposited up to and above the N-type contact structure, thereby shorting this structure to the N-type contact. It is unique.

Step 14. Wash off the mask (usually called lift-off). Ashing of all organic matter from O2 discum or wafer.

Step 15. A dielectric deposit (usually ~ 2000A SiNx) is used as the non-conductive separation barrier.

Step 16. Photolithography is used to mask the unetched dielectric area.

Step 17. Plasma etching can be used to perform etching through the dielectric (usually a Fl-based etching agent), or wet etching such as BOE (buffered oxide etch) (buffered oxide etching) can be used.

Step 18. Wash off the mask. Ashing of all organic matter from O2 discum or wafer.

Step 19. Photolithography is used to mask areas where solder metal is not deposited.

Step 20. The area is plated with Cu if a ~ 4-5 μm metal (usually Au) or diffusion barrier may have been deposited first.

Step 21. Photolithography is used to mask areas where solder does not deposit.

Step 22. A solder metal (usually an AuSn / Au eutectic composition having an atomic weight of 80% Au / 20% Sn) is deposited. The total thickness of the AuGe layer is ~ 40,000 A (4 microns) or more, and Au of ~ 500 A or more is used at the top to prevent any oxidation of Sn. This layer can be patterned and deposited on the submount, with the electrical waveguide glued to the laser grid.

U.S. Patent Application Publication No. 2017/0033535 Embodiment 3-Oxidation of Top Emissions In a third embodiment, oxidation is used instead of ion implantation to create a grid of top emission lasing regions within a single structure. .. For example, patterned etching can separate conductive paths within a single structure, thereby creating a grid of light sources. This structure exhibits a plurality of laser emission points from a single structure. The lasing structure is separated from the ground contacts forming the outer periphery of the chip by the etching region. This structure for the third embodiment is top emitting. The conductive area of the grid is where the light is emitted. The positive electrical contact may be a grid with an opening where the light is emitted.

The epitaxial material of the laser wafer may be a VCSEL design, most VCSELs are top emitting. Signal delivery using a p-guided pad is typically done on a laser wafer, but in an oxidized single structure embodiment with a back emission design, the waveguide is from an n-type material or layer of laser. It should be understood that they may be on separate substrates that are separated.

FIG. 7, which shows an example of the third embodiment, shows an exemplary pattern that is etched onto a wafer for the purpose of creating a single structure that allows lasing at multiple points. The single structure of an embodiment, such as the embodiment shown in FIG. 7, has significantly higher stiffness than a thin column made of a brittle crystalline material as taught by US Patent Application Publication No. 2011/01765667. It should also be understood that patterns in the lasing area other than the pattern shown in FIG. 7 may be adopted where desired by the practitioner, as described in connection with the embodiments discussed above. ..

In FIG. 7, the diagonal stripe area is preferably etched downward to create a patterned single mesa structure in the center of the separation trench. All shaded striped areas are preferably etched downwards to the N-shaped electrical conductive layer 705 at the bottom of FIG. 7A, or generally to electrical contacts where larger separation trenches are embedded as an epitaxial design. It will be etched, whereas the smaller patterned etching area must reach deeper than the active region separating the lasing points. The patterned structure in the center of the separation trench is a single structure with "molded" holes etched into this structure.

The holes in a large single mesa are large in this case. These pores allow the layers within the epitaxial region to oxidize in this oxidation process environment. The oxide layer has a high aluminum content and forms AlO ₂ that grows laterally through the layer until the end of the oxidation process. The white area is the surface of the chip, and the dotted line is the place where oxidation limits the current flow to the non-oxidized area only. The holes in this large single mesa are large in this case. These pores allow the layers within the epitaxial region to oxidize in this oxidation process environment. Oxidized layers can be formed using layers with high Al content in the epidesign structure embedded beneath the surface. The etching area exposes the layer that will be placed in the oxidation chamber, allowing this exposed layer to oxidize inward, where AlO ₂ passes through the layer until the end of the oxidation process. It grows laterally. As the length of oxidation increases in this thin layer, the dielectric material of AlO ₂ formed during the oxidation process separates or closes the current path. When area 7005 is etched, oxidation continues to grow until only area 7008 becomes conductive, directing current so that this area or portion of the epitaxial layer passes through this section. An electrically conductive area allows current flow to pass through the quantum well (see reference numeral 707 in FIG. 7A) when light is trapped in the cavity between the p-type mirror 709 and the N-type mirror 706. Create lasing.

In FIG. 7, the oxidation length can be seen as a dotted line, all approximately equal distances from any one exposed edge or hole in a large single structure with holes formed in it. .. FIG. 7 further shows a large single mesa ground structure. Three cross-sectional views are shown to show where FIGS. 7A, 7B, and 7C are located. Note that FIG. 7B clearly shows through this cross section that the central mesa is a single structure.

Figure 7 shows:
7001 Frame for electrical contact of electrical waveguide to ground (single short circuit mesa)
7002 Etched area that separates a large single mesa from the ground frame 7003 Single mesa structure with etched holes 7004 In the edge to maintain the edge of the single mesa structure in an oxidized and non-conductive state One indent 7005 Etched holes in a single mesa structure 7006 Oxidation pattern around any etched edge 7007 Overlapping oxidation areas that do not allow current flow 7008 Laser aperture that allows current to flow freely (Similar to 761 in FIG. 7B)
7009 Shows the gaps in the short-circuit mesa structure to reduce the capacitance from the ground to the signal pad on the electrical waveguide.

7A, 7A2, and 7B are side views of an exemplary embodiment of FIG. 7.

FIG. 7A2 shows an etched hole 727 that allows the formation of oxidation 731, which confine the current to region 761 of FIG. 7B for the formation of the laser beam 763.

Reference numeral 706 in FIG. 7A is a diffraction Bragg reflector (DBR) for a p-type mirror, which has one or more layers 708 in it with a very high aluminum content, which is a high temperature. When exposed to high humidity conditions, the 708 is oxidized, confining the current in area 761 shown in FIG. 7B, where the laser beam exits. The N-type mirror DBR709 has a conductive layer 705 for allowing current to flow out through an N-type metal ohm contact to the plating 782 (see FIG. 7C), and the plating 782 has a single ground mesa structure 718 (FIG. 7A). Further above it, it reaches the solder 717 and is electrically connected to the N-type plating on the GSG waveguide 716 and further to the inside of the N-type contact 175 of the waveguide.

Current confinement is an important point of semiconductor lasers. The concept is to force the current flow away from the edges of this structure, thus eliminating the problem of current flowing near rough surface conditions that may be present due to etching. In addition, the current flow is ideally concentrated for the purpose of achieving lasing by increasing the current density in the material. Current confinement is by oxidation by allowing the high concentration layer of Al to be exposed to high temperature and high humidity conditions in the oxidation process enabled by the drilled holes (eg, this embodiment 3), or other. This is done with implants that make all areas non-conductive (see, eg, embodiments 1 and 2).

Figure 7A is:
701 Electrical waveguide substrate 702 Etching region that separates a large single mesa from the ground frame 703 N-type metal contact that is in electrical contact with the N-type contact layer 704 N-type mirror 705 N-type contact layer in the N-type mirror (Low resistance due to ohm contacts)
706 N-type mirror above the N-type contact area 707 Active region (quantum well)
Oxidation layer that blocks current in the 708 region 709 P-type mirror 710 Waveguide layer 711 Plated on top of P-type contact metal 712 Aperture in P-type contact metal and plated metal for laser beam outlet 713 Electricity Waveguide board 714 Ground contact of GSG electrical waveguide 715 Signal contact of GSG electrical waveguide 716 Solder-adhesive portion of GSG waveguide to laser chip 717 Solder-adhesive portion of GSG waveguide to laser chip 718 The frame structure electrically connected to the N-shaped contact region of the laser chip is shown.

FIG. 7A2 is a continuation of FIG. 7A, and FIG. 7A2 is:
721 GSG Electrical Waveguide Ground Contact 722 Plating on GSG Electrical Waveguide Ground Contact 723 Solder-Adhesive Part of GSG Waveguide to Laser Chip 724 GSG Electrical Waveguide Signal Contact 725 GSG to Laser Chip Solder-Adhesive Part of Waveguide 726 Plating on Signal Contact of GSG Electrical Waveguide 727 Etched Hole Region in Single Mesa Structure Allows Oxidation to Form Current Confinement Aperture 728 P-Type Plating on the top of the contact metal 729 Opening in the waveguide for electrical contact from plating to the P-shaped contact on the single mesa structure of the laser 730 Waveguide 731 Blocks current near the etched hole region Shows an oxide layer.

FIG. 7B is a cross-sectional view of FIG. 7 further showing an electrical connection and an electrical waveguide not shown in FIG. FIG. 7B shows a cross-sectional view through the aperture created by the oxide layer. The oxide layer is exposed to an oxidation process through the pores within the single structure shown in FIG. 7A. This figure further shows that this active mesa structure is truly a single mesa structure. FIG. 7B is:
751 GSG Electrical Waveguide Ground Contact 752 GSG Electrical Waveguide Ground Contact Plating 753 Solder-GSG Waveguide Ground Adhesion to Laser Chip 754 GSG Electrical Waveguide Signal Contact 755 GSG Electrical Waveguide Coating on the signal contact of the waveguide 756 P-type contact metal on the laser chip 757 Plating on the laser dielectric and opening in the P-type contact metal 758 Plating on the P-type contact metal 759 Solder-to the laser chip, GSG Waveguide Signal Adhesion 760 Dielectric layer that protects active mesa structure from N-type contacts 761 Current confinement aperture formed by openings in the oxide layer 762 Oxide layer dielectric 763 Propagates through metal openings Indicates a laser beam.

FIG. 7C is a cross-sectional view of the area where the P-type contact or signal of the GSG waveguide is located below the laser chip, where the N-type contact frame or single is grounded to the N-type contact of the laser. The structural mesa is above the GSG electrical waveguide. The large gap between the laser ground and the P-type signal pad reduces the capacitance of the circuit and allows for high frequency operation. Figure 7C shows:
780 Dielectric layer 781 N-type ohm-contact metal 782 Plating that short-circuits N-type metal contacts into a single ground mesa structure 784 N-type contact layer on the epitaxial growth side 785 Plating that makes electrical contact with the signal pad on the electrical waveguide 786 Metal signal pad lead on GSG electrical waveguide 787 Plating on ground pad of GSG electrical waveguide 788 Electrical waveguide substrate 789 The gap between the conductive signal pad structure and the N-type contact layer is electrostatic. Indicates to reduce capacity.

Process for Embodiment 3 of U.S. Patent Application Publication No. 2017/0033535 An exemplary embodiment of a process step for creating a single structure for Embodiment 3 using oxidative current confinement. It can be explained as follows.

Step 1. Photolithography is used to mask areas where P-metals are not deposited.

Step 2. A P-type metal (usually ~ 2000A TiptAu) is deposited.

Step 3. Photolithography lift-off and wafer cleaning. Ashing of all organic matter from O2 discum or wafer.

Step 4. A dielectric deposit (usually ~ <1000A SiNx) is used as the etching mask.

Step 5. Photolithography is used to mask areas of the dielectric that are not etched.

Step 6. Plasma etching can be used to perform etching through the dielectric (usually a Fl-based etching agent), or wet etching such as BOE (buffered oxide etch) (buffered oxide etching) can be used.

Step 7. Etch the pattern into the epitaxial material of the laser or light emitting diode. Stop on the substrate or doped electrical contact layer. Etching is usually Cl-based with a certain amount (high percentage) of BCl3.

Step 8. Wash off the mask. Ashing of all organic matter from O2 discum or wafer.

Step 9. Photolithography is used to mask areas where N-metals are not deposited.

Step 10. An N-type metal (usually a GeAu / Ni / Au eutectic composition having an atomic weight of 80% Au / 20% Ge) is deposited. An AuGe layer with an overall thickness of ~ 3000A or more and an Au of ~ 5000A or more with Ni of ~ 200A or more as other diffusion barrier metals.

Step 11. Wash off the mask (usually called lift-off). Ashing of all organic matter from O2 discum or wafer.

Step 12. A dielectric deposit (usually ~ 2000A SiNx) is used as the non-conductive separation barrier.

Step 13. Photolithography is used to mask areas of the dielectric that are not etched.

Step 14. Plasma etching can be used to perform etching through the dielectric (usually a Fl-based etching agent), or wet etching such as BOE (buffered oxide etch) (buffered oxide etching) can be used.

Step 15. Wash off the mask. Ashing of all organic matter from O2 discum or wafer.

Step 16. Photolithography is used to mask areas where no plating metal is deposited.

Step 17. The area is plated with a metal of ~ 4-5 μm (usually Au) or with Cu if the diffusion barrier may have been previously deposited.

Step 18. Photolithography is used to mask areas where solder does not deposit.

Step 19. A solder metal (usually an AuSn / Au eutectic composition having an atomic weight of 80% Au / 20% Sn) is deposited. The total thickness of the AuSn layer is ~ 40,000 A (4 microns) or more, and Au of ~ 500 A or more is used at the top to prevent any oxidation of Sn. This layer can be patterned and deposited on the submount, where the electrical waveguide is glued to the laser grid.

Step 20. Separate the laser chip from the wafer using cleaving or dicing.

Step 21. Design and manufacture electrical waveguides that align with the laser chip using a design that allows high frequency operation.

Step 22. Align the laser tip with the submount electrical waveguide and flip chip bond

U.S. Patent Application Publication No. 2017/0033535 Embodiment 4-Oxidation of Bottom Emission In a fourth embodiment, a single oxidized structure with multiple lasing regions is designed as a bottom radiator rather than a top radiator. 8 to 14C present the details of embodiment 4 and show the processes that can be used to make this embodiment. The light from the lasing grid is radiated through the substrate, forming a back radiator.

Light can pass through GaAs at wavelengths above ~ 900 nm. When the wavelength of light processed by the epitaxial design is in the range of ~ 900 nm or more, the GaAs substrate transmits light, that is, is transparent to light. When this epitaxial design includes an N-type mirror having a lower reflectance than the P-type mirror, a laser such as a VCSEL can emit light from the N-type mirror through the substrate. The laser beam will propagate through this material, and the substrate will collimate the light, spread the light, diverge the light, focus the light, or for optical components to guide the light. Can be a platform. This makes it possible to form an integrated optical circuit with very high luminance power. In this case, this single structure and ground contact can be integrated into a high speed electrical waveguide substrate, thereby allowing high frequency response from the entire grid. A ground-signal-ground electrical waveguide is ideal for this high-speed electrical waveguide. Another type of electrical waveguide that can be used is a microstrip waveguide (see FIG. 15), where a thin dielectric layer on the substrate separates the signal pad from the ground pad.

FIG. 8 is a diagram of a general epitaxial design. Any high speed design can be used for the VCSEL device. Figure 8 is:
81 GaAs substrate 82 Possible positions for low resistance contact layer 83 N-type mirror layer after contact area 84 Low resistance N-type contact area 85 N-type mirror layer after quantum well 86 Quantum well area 87 Oxidation Layer 88 P-type mirror 89 Shows a low resistance P-type contact layer.

FIG. 9 is a diagram of the first process carried out, which is the deposition of P-type metal. This is usually the Ti / Pt / Au layer at the top of the highly doped P-type contact layer that forms the ohm contact. Figure 9 shows:
91 P-metal forming ohm contacts after annealing process 92 Shows a low resistance P-type contact layer.

FIG. 10 is a top view of etching the epitaxial layer in the downward direction up to the N-type contact layer. FIG. 10 shows the following:
1001 Area etched up to N-type contact layer 1002 Single mesaground structure 1003 Single mesaactive structure 1004 Etched holes to enable oxidation process aimed at forming apertures 1005 Conductive current confinement (conductive) The area between all the pores where the oxidation that forms the current confinement) is absent.

10A is a cross-sectional view A of FIG. 10 formed before the oxidation process, and FIG. 10A2 is a cross-sectional view A of FIG. 10 formed after the oxidation process. FIG. 10A2 is:
120 Demonstrates oxidation that completely blocks the conductive path near any etching area exposed during the oxidation process.

FIG. 10B is a cross-sectional view B of FIG. 10 showing a location where a current confinement aperture is formed in the area shown. This figure shows a section of a single mesa, the cross section of which is not perforated, and this figure allows for a more robust structure in which this mesa structure is suitable for the bonding process. It clearly shows that it has a one-mesa structure. FIG. 10B is:
125 The current confinement aperture is a conductive region of a single mesa structure. 126 An oxide layer formed as a dielectric layer near the place where the pores are etched 127 P-type metal contact layer is shown.

FIG. 11 shows a deposited dielectric layer patterned with open via "holes" for electrical contact to the epitaxial contact layer and for sealing the semiconductor for high reliability. ing. FIG. 11 is:
1101 Patterned dielectric layer with openings or "vias" 1102 Openings within the dielectric layer up to P-type contact metal 1103 Contact layer on a single mesaground structure.

FIG. 12 shows an N-shaped metal contact after deposition. Figure 12 shows:
1201 N-type contact metal is depicted as being deposited over an N-type contact to make an electrical connection to the N-type contact layer through a hole.

FIG. 13 shows the next step of plating the top of a single grounded frame region with a metal that shorts the N-shaped contact region, where the single grounded frame region is the ground of the GSG waveguide. It is adhered to the pad and is electrically conductive. This plating further adds the height of the active region to reduce capacitance and removes heat from the active region of the device, giving the device even better performance. The plating on the active single structure is separated from the N-type mirror and N-type contact area by a dielectric layer. FIG. 13 is:
1301 Dielectric layer that covers the active region and prevents plating that extends to the pores of the single mesa structure 1302 Plating that covers a single grounded mesa structure that is short-circuited to the N-type contact area through the N-type contact metal. 1303 Plating covering the active structure, extending to the holes in the active region, where cooling can occur through the high thermal conductivity of the plated metal 1304 GSG For being adhered to the ground of the electrical waveguide and electrically connected , Shows a plated metal extending over a single frame structure.

FIG. 14a shows the solder deposited on the laser chip. This functions as an electrically conductive adhesive layer between the laser chip and the high-speed electric waveguide. FIG. 14a is:
1401 Indicates a solder deposit.

FIG. 14b shows the alignment of the GSG electrical waveguide before bonding. FIG. 14b is:
1403 Submount for GSG high-speed electric waveguide 1404 Ground pad for GSG high-speed electric waveguide 1405 Signal pad for GSG high-speed electric waveguide 1406 Accumulated on the conductive area of GSG high-speed electric waveguide Shows the plated metal.

FIG. 14C shows a laser chip bonded to a GSG electrical waveguide. It is shown that the gap in a single grounded mesa enables high speed operation by reducing capacitance.

Embodiment 5 of U.S. Patent Application Publication No. 2017/0033535
In a fifth embodiment, microstrip or stripline electrical waveguides are used instead of GSG waveguides, as shown in FIG. This embodiment can also have the gaps mentioned in FIG. 14c above. This electrical waveguide can also be formed by a ground layer below the thin dielectric, with signal leads on top of the dielectric that also forms the stripline or microstrip waveguide. An opening in the dielectric can be used to contact the ground portion of the lasing grid. The width of the line and the thickness of the dielectric can be controlled to create an intrinsic impedance value for the circuit to match the characteristics. It should be understood that this technique is also used in other embodiments, such as Embodiment 2 or any of the embodiments discussed below. The figure in FIG. 15 shows a cross section spanning an active single mesa structure:
151 Waveguide board 152 Metal ground pad that spans the entire waveguide 153 Dielectric layer that separates the ground from the signal pad 154 Metal signal pad 155 Metal plating on the signal pad 156 Electrical signal pad to a single active mesa Metal plating on a 157 ground pad that is solder to connect to and is shown to have gaps or holes etched into it 158 Electrically connect a ground pad to a single grounded mesa Solder

Embodiment 6 of U.S. Patent Application Publication No. 2017/0033535
FIG. 16 shows a sixth embodiment. In FIG. 16, this structure is unique in that it leaves a path for directing a portion of the light at each lasing point to another laser next to it for the purpose of keeping the lasing in phase. In this example, the laser 161 has a portion of its downwardly reflected outer mode structure 162 up to the adjacent laser aperture 163, the laser aperture 163 producing light in phase with 162. The in-phase laser is 164, reflected from the angled reflective surface 165, and returns to the aperture of the adjacent laser 167, which is in-phase with 164 and 161 and repeats this shape. An angled area and / or reflection area 164 just outside the lens or output area can divert a small portion of the light that overflows the lens or output area to the adjacent lasing grid. Enables a coherent lasing grid. Part of the light from adjacent lasing points is injected into the lasing points that set up the lasing points that are homeomorphic to each other. This allows for coherent operation of all lasing points as this structure directs some of the light from each laser to the laser next to it. Reflectance, distance, and angle are calculated very accurately by those skilled in the art of optical modeling. Over the years, coherent behavior is an advantage that has avoided the behavior of laser arrays. FIG. 16 is:
161 Large aperture laser with wide divergence that emits only a portion of the light 162 A portion of the light from the laser 161 is reflected towards the aperture 163 163 A laser whose reflectance matches the phase of the light from 162 Aperture 164 Large aperture laser with wide divergence that emits only part of the light 165 Output Angled reflective surface on the back of the laser chip just outside the aperture 166 Reflected beam 167 in phase with the laser grid 164 Shown is a large aperture laser with a wide divergence that emits only a portion.

Embodiment 7 of U.S. Patent Application Publication No. 2017/0033535
FIG. 17 shows a seventh embodiment. In FIG. 17, the back side of the lasing grid chip has an etched pattern for reorienting the laser beam 172 towards a particularly beneficial area. This is achieved by the Diffractive Optical Element (DOE) 171, which has an etched surface, and when light travels through this portion, the angle of this surface is a beam, depending on the angle of the surface of the DOE. Or it is done like 175 to change the direction of the light. It is used to collimate or diverge light, or to guide or homogenize light. FIG. 17 does not show an electrical waveguide. The mode is controlled by the size of the aperture and the characteristics of the reflective surfaces 173 and 174. Figure 17 shows:
171 Beam 172 Diverted Laser Grid Beam 172 Laser Grid Beam Emitted from Aperture 173 Mirror Contact and Back 174 Back Emitting Laser Grid Mirror Contact And the back 175 shows a reoriented beam from the laser grid.

Embodiment 8 of U.S. Patent Application Publication No. 2017/0033535
FIG. 18 shows an eighth embodiment. In FIG. 18, a patterned diffraction grating 184 (which is the opposite angular pattern of the DOE in FIG. 17) is installed on the back side of the laser wafer designed for back emission VCSEL, above the emission point 181. Alternatively, it is etched to direct the lazing point to the outside 185 of this grating. From this lens, all lasers appear to come from a single point 186 behind the chip, forming a virtual point source, where the microlens 187 is a virtual behind the chip. It can be used to collimate a beam from a focused source. FIG. 18 is:
181 Mirror contacts and back for back emitting laser grid 182 Aperture making laser characteristics 183 Laser beam from laser grid 184 Surface of diffractive optics (DOE) angled for unique overall beam grid characteristics 185 Diverted beam from the laser grid 186 A focused virtual light source from all beams when viewed from lens 187 187 A microlens with focus on a virtual focused point 186.

Embodiment 9 of U.S. Patent Application Publication No. 2017/0033535
FIG. 19 shows a ninth embodiment. FIG. 19 shows a cross section of embodiment 3 that has been glued, etched, and oxidized, provided that one microlens is aligned with the other microlens and even this single mesa. Having a microlens machined on the back of the laser chip, positioned in such a way that the position of one microlens is slightly offset for the purpose of redirecting the laser beam emitted from the structure. Except. Embodiment 3, which is referenced for this configuration, is any embodiment of the rear emission embodiment described above and a microlens array mounted on a chip or positioned above the output grid. It should be understood that and can be used. This microlens array can have values related to the pitch of the photoconducting grid points, but the light emitted by the lasing points is integrated with the beam at the virtual point source in front of or behind the chip. Lenses 74 with slightly different pitches are used to guide them to a single area where they become or appear to be one. If the pitch of the microlens is less than the pitch of the laser, the microphone lens directs the laser away from the center towards or inward the point in front of the chip. If the pitch of the microlens array is greater than the pitch of the laser grid, the light will be directed outward as shown in FIG. Figure 19 shows:
71 Laser substrate 72 N-type mirror 73 N-type contact area 74 Microlens slightly offset from the laser to guide the laser light outward 75 Active region or quantum well 76 Oxide layer that creates current confinement in the active region 77 Single Etching trench creating separation from one-ground structure and active single mesa structure 78 P-type metal contact 79 Holes etched into single mesa structure to allow oxidation 80 Laser tip and fast electrical conduction Solder that electrically connects the wave tube 81 GSG electric waveguide signal pad 82 P-type mirror 83 GSG waveguide board 84 N-type contact layer that is in electrical contact with the ground pad of the GSG electric waveguide, and a single A ground pad for a plated 85 GSG electrical waveguide that short-circuits an N-type metal placed on a ground mesa is shown.

Embodiment 10 of U.S. Patent Application Publication No. 2017/0033535
FIG. 20 shows a tenth embodiment. FIG. 20 shows reducing the reflectivity of the N-type epitaxial output mirror 31 towards the non-lasing point and then increasing the reflectivity towards the reflective surface 231 on the back of the lazing grid extending the cavity. Shows that an extended cavity laser design can be achieved using a single grid structure. This structure reduces the feedback of the higher mode structure 233 in the cavity, thereby forming a more basic mode structure for the output beam 235 from the grid. Figure 20:
230 Arrow indicating the epitaxial region of an incomplete N-type power mirror 231 Reflection region made of a dielectric layer with a varying index of refraction 232 Laser beam cavity, here a laser wafer material that extends the cavity for mode exclusion Higher-order mode reflections that are not reflected back towards the 233 cavity with 234 Single-mode or lower-order mode in the cavity 235 Indicates single-mode or lower-order mode output from the extended cavity device.

Embodiment 11 of U.S. Patent Application Publication No. 2017/0033535
FIG. 21 shows an eleventh embodiment. In FIG. 21, the VCSEL structure can be adapted to the laser grid design as in the above embodiment, with the back of the lasing chip where the output reflector of the lasing grid (deposited on the lens shape 241) emits light. , The focusing feedback mechanism (focus arrow 243) can have a convex shape 241 or concave shape under the reflector to better form, and this focusing feedback mechanism eliminates higher order modes. , Can be designed to have a single mode lasing output 245 from each grid area. In this case, the overall lasing structure will have a low M2 value. Lenses or microlenses may be added to collimate the output. FIG. 21 is:
240 Arrow indicating the epitaxial region of an incomplete N-type power mirror 241 Reflection region 242 made of a dielectric layer with a variable index of refraction deposited on a microphone lens structure etched on a laser substrate or wafer. Single-mode beam reflected in the cavity 243 Light from the optics on the surface of the chip, from the edge guided back to the extended cavity 244 More than the single-mode beam in Figure 20. Higher selective, higher selective, single mode 245 high quality single mode beam output 246 shows an epitaxial mirror that reflects more strongly.

Embodiment 12 of U.S. Patent Application Publication No. 2017/0033535
FIG. 22 shows a twelfth embodiment. In FIG. 22, the VCSEL structure can be adapted to a laser grid design as in the above embodiment, except that the beam coming straight out of the lens passes through an external microlens array, which is the external microlens array of the laser. It is designed to have microlenses with a pitch different from the pitch, thereby, as in many of the above embodiments, of the beam to or from a single location. Except that it can be possible to turn around. Another form of this technique can also use a concave lens that is aligned with the laser grid and formed at the bottom of an external lens array with a pitch equal to the laser grid, whereas with a different pitch than the laser grid. The convex laser array with is on the top side. Another technique for guiding the beam is to use DOE as the top optic instead of the convex microlens above the external lens array. 252 is the light reflected back to the center of the aperture to create a stronger single-mode beam, while 253 has a reflective coating that completes the cavity of the laser power mirror. Reference numeral 254 is a cavity, which has an antireflection coating deposited inside the outer lens cavity, while also depositing an antireflection coating on the top microlens array. Another technique is to use a planar reflection characteristic as shown in Figure 20 to complete the cavity mirror, which is an offset microlens array on the top side to divert the beam. Or it has a DOE on the top side. FIG. 22 shows:
250 Arrow indicating the epitaxial region of an imperfect N-power mirror 251 Single-mode beam reflected within an extended cavity 252 Return to the center that creates a strong single-mode cavity from an optical element on the surface of the chip Light from the edge, guided by 253 Reflective region made of a dielectric layer with varying refractive index deposited on a microphone lens structure that is etched onto a laser substrate or wafer 254 The lens to be etched is external Cavity 255 External Lens Array Transmissive Material to Avoid Touching the Lens Array 256 Single Mode Beam Output by Extended Cavity Laser 257 From a lens array with a pitch different from the pitch of the laser leading the beam Microlens 258 Guided Single Mode Beam

Claims (30)

It ’s a device,
A laser emission epitaxial structure having a front surface and a back surface, the laser emission epitaxial structure is back emission, has a plurality of laser regions in a single mesa structure, each laser region has an aperture, and a laser beam passes through the aperture. A laser emission epitaxial structure that is radiated in a controllable manner,
A microlens array that is placed on the back surface of the laser emission epitaxial structure and in which each microlens of the microlens array is aligned with the laser region of the laser emission epitaxial structure.
It features a non-coherent beam combiner that is positioned to combine multiple laser beams emitted from the aperture in a non-coherent manner.
apparatus. The apparatus according to claim 1, wherein each of the plurality of laser regions includes a laser cavity extending to the back surface of the laser emission epitaxial structure. The apparatus according to claim 2, wherein each of the laser cavities has an optical axis for emitting a laser beam, and the optical axis is perpendicular to the back surface of the laser emission epitaxial structure. The device according to claim 2 or 3, wherein the microlens is covered with a reflective coating and the laser beam from the emitted laser beam is reflected rearward through the laser cavity. The device of claim 4, wherein the microlens has a smooth radius of curvature so that the reflected laser light is concentrated in the center of the laser cavity. The apparatus according to any one of claims 1 to 5, wherein the microlens array is a photolithographic microlens array. The apparatus according to any one of claims 1 to 6, wherein the microlens array includes a plurality of graphene lens structures. The apparatus according to any one of claims 1 to 7, wherein the non-coherent beam combiner comprises a two-dimensional (2D) non-coherent beam combiner having overlapping focusing points. The apparatus according to any one of claims 1 to 7, wherein the non-coherent beam combiner comprises a three-dimensional (3D) non-coherent beam combiner having a plurality of overlapping focusing points. The apparatus according to any one of claims 1 to 9, further comprising an electrical waveguide configured to provide an electric current to the laser region. The apparatus according to claim 10, wherein each laser region is electrically insulated from other laser regions of the single mesa structure within the single mesa structure. The apparatus according to any one of claims 1 to 11, wherein the laser emission epitaxial structure includes a vertical cavity surface emitting laser (VCSEL) epitaxial structure. The apparatus according to any one of claims 1 to 11, wherein the laser emission epitaxial structure includes a vertically extended resonator surface emitting laser (VECSEL) epitaxial structure. The apparatus according to any one of claims 1 to 13, further comprising a plurality of laser emission epitaxial structures and a plurality of microlens arrays configured as a laser grid array. The device according to any one of claims 1 to 14, wherein the device is configured to controlally emit a laser beam from the laser region as a directed energy weapon for drone defense. The way
A step of generating a plurality of laser beams by selectively applying a current to a laser emission epitaxial structure having a front surface and a back surface. The laser emission epitaxial structure is back emission, and a plurality of lasers are contained in a single mesa structure. With regions, each laser region has an aperture, and the laser beam is radiated through the aperture, with steps.
A step of guiding the generated laser beam to a microlens array placed on the back surface of the laser emission epitaxial structure, in which each microlens of the microlens array is aligned with the laser region of the laser emission epitaxial structure. ,
Including the step of non-coherently coupling the laser beam emitted from the aperture,
Method. 16. The method of claim 16, wherein each of the plurality of laser regions comprises a laser cavity that extends to the back of the laser emission epitaxial structure. 17. The method of claim 17, wherein each of the laser cavities has an optical axis for laser beam emission, the optical axis being perpendicular to the back surface of the laser emission epitaxial structure. 17. The method of claim 17 or 18, further comprising reflecting the laser light from the emitted laser beam such that it returns through the laser cavity through a reflective coating that covers the microlenses of the microlens array. 19. The method of claim 19, wherein the microlens has a smooth radius of curvature so that the reflected laser light is concentrated in the center of the laser cavity. The method according to any one of claims 16 to 20, wherein the microlens array is a photolithographic microlens array. The method according to any one of claims 16 to 21, wherein the microlens array comprises a plurality of graphene lens structures. The method of any one of claims 16-22, wherein the non-coherently coupling step comprises performing a two-dimensional (2D) non-coherent beam coupling using overlapping focusing points. The method of any one of claims 16-22, wherein the non-coherently coupled step comprises performing a three-dimensional (3D) non-coherent beam coupling using a plurality of overlapping focusing points. The method according to any one of claims 16 to 24, further comprising the step of applying an electric current to the laser emission epitaxial structure via an electrical waveguide. 25. The method of claim 25, wherein each laser region is electrically insulated from the other laser regions of the single mesa structure within the single mesa structure. The method according to any one of claims 16 to 26, wherein the laser emission epitaxial structure comprises a vertical resonant surface emitting laser (VCSEL) epitaxial structure. The method according to any one of claims 16 to 26, wherein the laser emission epitaxial structure comprises a vertically extended resonant surface emitting laser (VECSEL) epitaxial structure. The method according to any one of claims 16 to 28, further comprising a plurality of laser emission epitaxial structures and a plurality of microlens arrays configured as a laser grid array. The method of any one of claims 16-29, wherein the combined laser beam functions as a directed energy weapon for drone defense.

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