Patent Publication Number: US-2022236503-A1

Title: Integrated Photonics Device Having Integrated Edge Outcouplers

Description:
CROSS REFERENCE OF RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/969,034, filed Aug. 11, 2020, which is a national phase application under 35 U.S.C. § 371 of PCT Application PCT/US2019/017842, filed Feb. 13, 2019, which claims benefit of U.S. Provisional Patent Application No. 62/630,018, filed on Feb. 13, 2018, the contents of which are hereby incorporated by reference as if fully disclosed herein. 
    
    
     FIELD OF DISCLOSURE 
     This relates generally to an integrated photonics device configured for measuring one or more properties of a sample volume. More specifically, the integrated photonics device can include integrated edge outcouplers. 
     BACKGROUND 
     One application for optical sensing systems can be to measure one or more properties of a sample volume. The optical sensing system can include an integrated photonics device including a plurality of optical components such as light sources and detectors. The placement and alignment accuracy of the light sources and detectors relative to each other can affect the accuracy of the measurement. For example, the alignment of the optical components can affect the accuracy of the selective detection of return light measured by the detectors that have a certain path length. 
     SUMMARY 
     Described herein is an integrated photonics device for determining one or more properties of a measured sample volume. The integrated photonics device can include a light emitter configured to emit light through a waveguide formed by a plurality of layers. The light can propagate through the waveguide to one or more integrated edge outcouplers. The integrated edge outcoupler can redirect the light to emission optics, which can then collimate, focus, and/or direct the light to an emission region located on an external surface of the device. The light can interact with material included in a measured sample volume. The light can undergo one or more scattering events in the measured sample volume, where the scattering event(s) can cause the light to return to the device. The return light can enter into the device via one or more windows. Detection/collection optics can be used to collimate, focus, and/or direct the return light to the detector array. A detector may also be attached to the supporting material above the outcoupler and attached directly to the outcoupler. The detector array can generate a plurality of signals to be analyzed by a controller or processor for determining one or more properties of the measured sample volume. 
     The integrated photonics device can include a hermetically sealed enclosure, which can include optical components, electrical components, and/or thermal components. For example, the optical components can include the emission and detection optics and the detector array. The hermetic seal can reduce the amount of moisture and/or contamination that may affect the measurement, analysis, and/or the function of the individual components within the sealed enclosure. Additionally or alternatively, the hermetic seal can be used to protect the components within the enclosure from environmental contamination induced during the manufacturing, packaging, and/or shipping process. The electrical components can include one or more layers disposed on a supporting layer and configured to route electrical signals from the optical components to regions outside of the hermetic seal. The thermal components can include, but are not limited to, one or more passive thermal slugs and active thermoelectric devices configured to relocate heat generated by the optical components to the system interface of the device. 
     The integrated photonics device can also include an integrated edge outcoupler. The integrated edge outcoupler can be formed by creating one or more pockets in the layers of a die. Outcoupler material can be formed in the pocket and, optionally, subsequent layers can be deposited on top of the outcoupler material. The edge of the die can be polished until a targeted polish plane is achieved to form the outcoupler. Once the outcoupler is formed, the die can be flipped over and other components can be formed. Once the other components are formed, a frame can be bonded to the supporting layer, and a hermetic seal can be formed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  illustrates a block diagram of an exemplary optical sensing system according to examples of the disclosure. 
         FIG. 1B  illustrates an exemplary process flow for measuring sample properties according to examples of the disclosure. 
         FIGS. 2A-2B  illustrate cross-sectional and top views, respectively, of an exemplary portion of an integrated photonics device according to examples of the disclosure. 
         FIGS. 3A-3B  illustrate cross-sectional and top views, respectively, of a thermal slug occupying the space around the optics in an integrated photonics device according to examples of the disclosure. 
         FIG. 4  illustrates an exemplary process flow for forming the integrated photonics device according to examples of the disclosure. 
         FIGS. 5A-5B  illustrate cross-sectional views of an integrated photonics device during some of the steps of its formation according to examples of the disclosure. 
         FIGS. 5C-5D  illustrate cross-sectional and top views, respectively, of an exemplary die after outcoupler material is formed in the pockets according to examples of the disclosure. 
         FIG. 5E  illustrates a top view of an exemplary wafer having multiple dies according to examples of the disclosure. 
         FIG. 5F  illustrates a cross-sectional view of an exemplary die including additional layers deposited on top of the outcoupler material according to examples of the disclosure. 
         FIG. 5G  illustrates a cross-sectional view of an exemplary die having a polished edge according to examples of the disclosure. 
         FIGS. 5H-5J  illustrate cross-sectional, top, and planar views, respectively, of a die including bonding bumps formed on the layers according to examples of the disclosure. 
         FIG. 5K  illustrates a top view of a wafer including multiple dies having the bonding bumps formed on the layers of the multiple dies according to examples of the disclosure. 
         FIGS. 6A-6C  illustrate cross-sectional and top views of fiducials included in an integrated photonics device according to examples of the disclosure. 
         FIG. 7A  illustrates an exemplary integrated device for determining the properties of a sample according to examples of the disclosure. 
         FIG. 7B  illustrates an exemplary method for determining the properties of a sample using the integrated device according to examples of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description of examples, reference is made to the accompanying drawings in which it is shown by way of illustration specific examples that can be practiced. It is to be understood that other examples can be used and structural changes can be made without departing from the scope of the various examples. 
     Various techniques and process flow steps will be described in detail with reference to examples as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of one or more aspects and/or features described or referenced herein. It will be apparent, however, to one skilled in the art, that one or more aspects and/or features described or referenced herein may be practiced without some or all of these specific details. In other instances, well-known process steps and/or structures have not been described in detail in order to not obscure some of the aspects and/or features described or referenced herein. 
     Further, although process steps or method steps can be described in a sequential order, such processes and methods can be configured to work in any suitable order. In other words, any sequence or order of steps that can be described in the disclosure does not, in and of itself, indicate a requirement that the steps be performed in that order. Further, some steps may be performed simultaneously despite being described or implied as occurring non-simultaneously (e.g., because one step is described after the other step). Moreover, the illustration of a process by its description in a drawing does not imply that the illustrated process is exclusive of other variations and modification thereto, does not imply that the illustrated process or any of its steps are necessary to one or more of the examples, and does not imply that the illustrated process is preferred. 
     Described here is an integrated photonics device for determining one or more properties of a measured sample volume. The integrated photonics device can include a light emitter configured to emit light through a waveguide formed by a plurality of layers. The light can propagate through the waveguide to one or more integrated edge outcouplers. The integrated edge outcoupler can redirect the light to emission optics, which can then collimate, focus, and/or direct the light to an emission region located on an external surface of the device. The light can interact with material included in a measured sample volume. The light can undergo one or more scattering events in the measured sample volume, where the scattering event(s) can cause the light to return to the device. The return light can enter into the device via one or more windows. Detection optics can be used to collimate, focus, and/or direct the return light to the detector array. The detector array can generate a plurality of signals to be analyzed by a controller or processor for determining one or more properties of the measured sample volume. 
     The integrated photonics device can include a hermetically sealed enclosure, which can include optical components, electrical components, and/or thermal components. For example, the optical components can include the emission and detection optics and the detector array. The hermetic seal can reduce the amount of moisture and/or contamination that may affect the measurement, analysis and/or the function of the individual components within the sealed enclosure. Additionally or alternatively, the hermetic seal can be used to protect the components within the enclosure from environmental contamination induced during the manufacturing, packaging, and/or shipping process. The electrical components can include one or more layers disposed on a supporting layer and configured to route electrical signals from the optical components to regions outside of the hermetic seal. The thermal components can include one or more thermal slugs configured to relocate heat generated by the optical components to the system interface of the device. 
     The integrated photonics device can also include an integrated edge outcoupler. The integrated edge outcoupler can be formed by creating one or more pockets in the layers of a die. Outcoupler material can be formed in the pocket, and optionally, subsequent layers can be deposited on top of the outcoupler material. The edge of the die can be polished until a targeted polish plane is achieved to form the outcoupler. Once the outcoupler is formed, the die can be flipped over and other components can be formed. Once the other components are formed, a frame can be bonded to the supporting layer, and a hermetic seal can be formed. 
     An overview of the components included in an exemplary integrated photonics device and operation thereof are now described, with detailed descriptions provided below.  FIG. 1A  illustrates a block diagram of an exemplary optical sensing system according to examples of the disclosure.  FIG. 1B  illustrates an exemplary process flow for measuring sample properties according to examples of the disclosure. The system  100  can include an interface  180  (e.g., a system interface), an optical unit  190 , a light emitter  107 , a detector  130 , and a controller  140 . The system  100  can include an integrated photonics device, and the interface  180  can include an external surface of the device, which can accommodate light transmission through it, among other things. The interface  180  can include an emission region  182 , a reference  108  (optional), and a detection region  156 . In some examples, the emission region  182  can include one or more components (e.g., an aperture layer) configured to limit the optical path lengths and/or angles of light entering the system  100 . By limiting the optical path lengths and/or angles of light, the light incident on, or exiting from, a measured sample volume  120  can also be limited. Optical unit  190  can include an absorber or light blocker  192 , optics  191  (e.g., lenses), optics  194  (e.g., a negative microlens), and light collection optics  116  (e.g., a positive microlens). In using the system, the measured sample volume  120  can be located near, close to, or touching at least a portion (e.g., interface  180 ) of the system  100 . The light emitter  107  can be coupled to the controller  140 . The controller  140  can send a signal (e.g., current or voltage waveform) to control the light emitter  107 , which can emit light (step  153  of process  150 ). The light emitter  107  can include a plurality of waveguides, in some examples. The light emitter  107  can emit light towards the emission region  182  (step  155  of process  151 ). 
     The emission region  182  can be configured to allow light to exit the system  100  towards the measured sample volume  120 . Depending on the nature of the measured sample volume  120 , light can penetrate a certain depth into the measured sample volume  120  to reach one or more scattering sites and can return (e.g., reflect and/or scatter back) towards the system  100 . The return light can enter back into the system  100  at the detection region  156  (step  159  of process  151 ). The return light that enters back into the system can be collected by light collection optics  116 , which can direct, collimate, focus, and/or magnify the return light (step  161  of process  151 ). The return light can be directed towards the detector  130  (e.g., a detector array). The detector  130  can detect the return light and send an electrical signal indicative of the amount of detected light to the controller  140  (step  163  of process  151 ). 
     The light emitter  107  can optionally emit light towards the reference  108  (step  165  of process  151 ). The reference  108  can redirect light towards optics  194  (step  167  of process  151 ). The reference  108  can include, but is not limited to, a mirror, a filter, and/or a sample with known optical properties. Optics  194  can direct, collimate, focus, and/or magnify light towards the detector  130  (step  169  of process  151 ). The detector  130  can measure light reflected from the reference  108  and can generate an electrical signal indicative of this reflected light (step  171  of process  151 ). The controller can be configured to receive at least two electrical signals from the detector  130 . In some instances, one electrical signal can be indicative of return light from the measured sample volume  120 , and another electrical signal can be indicative of light reflected from the reference  108 . The different electrical signals can be a time-multiplexed signal, for example. The electrical signal at a given instance in time can be based on whether the light is sent to the measured sample volume or the reference. In other instances, the two or more electrical signals can be received by different detector pixels simultaneously and may include different light information. The controller  140  (or another processor) can determine the properties of the sample from the electrical signals (step  173  of process  151 ). 
     In some examples, when the system is measuring the properties of the sample and the reference, light emitted from the light emitter  107  can reflect off a surface of the sample back into the system  100 . Light reflected off the interior walls or components can be referred to as the interface reflected light  184 . In some examples, the interface reflected light  184  could be light emitted from the light emitter  107  that has not reflected off the measured sample volume  120  or the reference  108  and can be due to light scattering within the system  100 . Since the interface reflected light  184  can be unwanted, the absorber or light blocker  192  can prevent the interface reflected light  184  from being collected by optics  194  and light collection optics  116 . In this manner, the system can prevent the interface reflected light  184  from being measured by the detector  130 . 
     A detailed description of an exemplary integrated photonics device is now provided.  FIGS. 2A-2B  illustrate cross-sectional and top views, respectively, of an exemplary portion of an integrated photonics device according to examples of the disclosure. In using the device, the measured sample volume (e.g., measured sample volume  120  illustrated in  FIG. 1A ) can be located close to the system interface  280 . The device can include one or more windows  201  located at the system interface  280 . The window(s)  201  can include one or more transparent and thermally conductive materials such as sapphire, silicon, or a combination thereof. 
     The measured sample volume can include one or more locations, which can include one or more scattering sites associated with scattering event(s). The device  200  can be configured to reconstruct the optical paths in the measured sample volume. For example, the device  200  can be configured to reconstruct angles and locations of light received at the detection regions  256  to another place (e.g., a plane located closer to the detector array  230 ). Reconstruction of the optical paths can be performed using one or more layers of optics (e.g., optics  216 ). The device  200  can include any number of layers of optics; the one-layer of optics shown in the figure is just one example. 
     The device  200  can include multiple components, where the multiple components can be formed on or attached to a supporting layer  242 . The supporting layer  242  can include any type of material such as silicon. At least some of the multiple components can include optical components. Exemplary optical components can include a light emitter  207 , a detector array  230 , optics  216 , optics  291 , and an outcoupler  209 . Other optical components (not shown) can include optical traces, multiplexers, reflectors, and the like. The device can also include one or more electrical components, such as layer  210 , layer  219 , and bonding bumps  236 . 
     The device  200  can also include a frame  214 , which can be used to hermetically seal the optical components within the cavity between the supporting layer  242  and the system interface  280 . The frame  214  can assist in creating the hermetic seal by being bonded to the supporting layer  242 . In some examples, the frame  214  include a conductive (e.g., metal) frame. The hermetic seal can reduce the amount of water located in the cavity and/or reduce the amount of contamination in the optical paths of the light included in the measurements. In some instances, at least a portion of the frame  214  can be at a location inside the perimeter of the supporting layer  242 , as shown in the figure. Bond pads (not shown) can be placed on the edge  245  of the supporting layer  242 . Wire bonds  247  can be used to connect the bond pads to a board (e.g., interposer  241  or board  243 ) located outside of the sealed enclosure. One or more traces (e.g., included in layer  219 ) can be used to electrically couple the active components in the sealed enclosure to the bond pads and/or wire bonds  247 , located outside of the sealed enclosure. In some examples, one or more layers  248  (dielectric layers and/or conductive layers) located between the frame  214  and the supporting layer  242  can be used for routing signals from the active components to the bond pads and/or wire bonds  247 . 
     As discussed above, the system interface  280  can include one or more emission regions  282  and one or more detection regions  256 . The emission region(s)  282  can be configured to allow light emitted by the light emitter  207  (and redirected by the outcoupler  209  and optics  291 ) to exit the device  200  at the system interface  280 . The detection region(s)  256  can be configured to allow return light to enter the device  200  to be redirected by optics  216  and detected by the detector array  230 . In some examples, certain detector pixels included in the detector array  230  can be associated with different optical path lengths to determine (e.g., estimate) the optical properties (e.g., absorbance) of the measured sample volume. 
     The detector array  230  can be located below (i.e., opposite the system interface  280 ) the optics  216 . In some examples, the optics  216  can be formed from the same material as the window(s)  201 . Between the detector array  230  and the optics  216 , the device  200  can include air, vacuum, or any medium with a refractive index that contrasts the refractive indices of the optics  216 . As discussed below, in some examples, the medium can include a thermal slug. 
     The device  200  can include one or more light emitters  207 . A light emitter  207  can be configured to emit light. The light emitter  207  can include any type of light source (including one or more waveguides (not shown)) capable of generating light. In some instances, the light emitter  206  can include a single light source. In other instances, the light emitter  207  can include a plurality of discrete light sources. A light source can include, but is not limited to, a lamp, laser, light-emitting diode (LED), organic light-emitting diode (OLED), electroluminescent (EL) source, quantum dot (QD) light emitter, super-luminescent diode, super-continuum source, fiber-based source, or a combination of one or more of these sources. In some examples, the light emitter  207  can be capable of emitting a single wavelength of light. In some examples, the light emitter  207  can be capable of emitting a plurality of wavelengths of light. In some examples, the light emitter  207  can include any tunable source capable of generating a short-wave infrared (SWIR) signature. In some examples, a light emitter  207  can include a III-V material, such as Indium Phosphide (InP), Gallium Antimonide (GaSb), Gallium Arsenide Antimonide (GaAsSb), Aluminum Arsenide (AlAs), Aluminum Gallium Arsenide (AlGaAs), Aluminum Indium Arsenide (AnnAs), Indium Gallium Phosphide (InGaP), Indium Gallium Arsenide (InGaAs), Indium Arsenide Antimonide (InAsSb), Indium Phosphide Antimonide (InPSb), Indium Arsenide Phosphide Antimonide (InAsPSb), and Gallium Indium Arsenide Antimonide Phosphide (GaInAsSbP). 
     Optics  291  can be configured to redirect, collimate, and/or focus light emitted by the light emitter  207  and redirected by the outcoupler  209 . Additionally, the optics  216  can be configured to redirect, collimate, and/or focus return light to be received by the detector array  230 . The device can further include an outcoupler  209 , which can be configured to redirect the light emitted by the light emitter  207 . In some examples, the outcoupler  209  can be located on the same layer as at least one of the layers  210 . For example, a side of the outcoupler  209  can contact the supporting layer  242 , and a side of the layers  210  can also contact the supporting layer. Optionally, the device can include a reflector  211  disposed on the outcoupler  209 . 
     The device  200  can include one or more layers  210  and/or one or more layers  219 . The layers  210  can include one or more conductive layers configured to route one or more signals to the light emitter  207 . For example, the layers  210  can be configured to route one or more signals from a controller (e.g., controller  140  illustrated in  FIG. 1A ) to control the light emitter  207 , which can emit light in response to the one or more signals. The layers  210  can also include one or more insulating layers. For example, the layers  210  can include multiple conductive layers electrically isolated by insulating layer(s). In some instances, the layers  210  can include one or more of encapsulation layers, passivation layers, planarizing layers, or the like. The layers  210  can be electrically connected to one or more components via bonding bumps  236 . Additionally or alternatively, the one or more components can be electrically connected to other components via the interposer  241 . 
     Additionally, the layers  219  can include one or more conductive layers configured to route one or more signals to the detector array  230 . For example, the layers  219  can be configured to route one or more signals from the detector array  230  to a controller (e.g., controller  140  illustrated in  FIG. 1A ). The layers  219  can also include one or more insulating layers. For example, the layers  219  can include multiple conductive layers electrically isolated by insulating layer(s). In some instances, layers  219  can also include one or more of encapsulation layers, passivation layers, planarizing layers, or the like. In some instances, the layers  219  can include one or more thermoelectric materials for stabilizing the temperature of the detector array  230 . In some examples, one or more layers  219  can include the same material as one or more of the layers  210 . In some examples, the device  200  can include one or more wire bonds, in addition to layers  219 , that can electrically connect the detector array  230  to the layers  219 . 
     In some examples, the device can include one or more traces (not shown) that connect layers  210  and layers  219 . The one or more traces can be routed out of the hermetically sealed cavity. In some instances, the device can include through-silicon vias (TSVs) (not shown) to electrically connect the layers  210  and the layers  219 . In other instances, the traces can be routed to the edges of the supporting layer  242 , under the frame  214 , and bonded to one or more components outside of the hermetic seal (e.g., using wire bonds  247  to connect to board  243 ) 
     Additionally, the device can include one or more thermal components, such as thermal slug, a heat sink, thermoelectric device, or the like. The thermal slug  232  can be configured to relocate heat from one location in the device to another. For example, the thermal slug  232  can be used to relocate heat from the light emitter  207  to the system interface  280 . The thermal slug  232  can be attached to the supporting layer  242  using the solder connection  234 . In some examples, the solder connection can be an under bump metallization made from a thermally conductive material such as nickel gold. In some examples, solder connection(s)  234  can be located in locations corresponding to the light emitters  207 . That is, a solder connection  234  can be located above (i.e., closer to the system interface  280 ) the light emitter  207  such that heat from the light emitter  207  can be relocated to the thermal slug  232  located above. In some examples, the solder connection  234  can have the same footprint as the light emitter  207 . In some examples, the each light emitter  207  can have a unique solder connection  234  and a unique thermal slug  232 . Additional solder connections  234  can be located in other areas of the device, e.g., to help connect frame  214  to the supporting layer  242 . 
     The device  200  can optionally include an underfill  244  and/or overfill  246 . The underfill  246  can fill the space located between the outcoupler  209  and the interposer  241 . The overfill  246  can be located in the space outside of the hermetically sealed cavity and can be used to, e.g., seal any wire bonds to prevent the wire bonds from breaking. 
     Although the descriptions given above and below pertain to a device, examples of the disclosure can include a system having multiple devices, where different components may be located in the different devices. 
     In some examples, the thermal slug included in the device can occupy the space around the optics.  FIGS. 3A-3B  illustrate cross-sectional and top views, respectively, of a thermal slug occupying the space around the optics in an integrated photonics device according to examples of the disclosure. Thermal slug  332  can be located around optics  316  and/or around optics  391 . One or more openings can be located in the optical paths of the emitted light and/or return light. For example, the openings  357  can allow return light entering through the system interface  380  to reach the detector array  330 . The openings  383  can allow emitted light from the light emitter  307  to reach the system interface  380 . With the thermal slug  332  located around one or more optics, the thermal slug  332  can relocate the heat from one or more components (e.g., the light emitter(s)  307 ) to the window  301 . In some examples, a light absorbing material can be deposited on the thermal slug  332  to help block/absorb unwanted light rays. The light absorber material can be an infrared absorbing material, for example. 
     In the above-described examples, the devices can include one or more thermally conductive adhesive materials (e.g., an epoxy) that bonds the thermal slug to another component. For example, a thermally conductive epoxy can be used to bond the window  201  to thermal slug  232  in device  200  illustrated in  FIG. 2A . Similarly, a thermally conductive epoxy can be used to bond the thermal slug  332  to supporting layer  342  in device  300  illustrated in  FIG. 3A . In some examples, the solder connection  334  can include the thermally conductive epoxy. In some examples, the same type of material can be used to connect the thermal slug  332  to the supporting layer  342  as used to connect the thermal slug  332  to the window(s)  301 . 
     The process for forming the edge outcoupler will now be described.  FIG. 4  illustrates an exemplary process flow for forming the integrated photonics device according to examples of the disclosure.  FIGS. 5A-5B  illustrate cross-sectional views of an integrated photonics device during some of the steps of its formation according to examples of the disclosure. Process  400  can begin by providing a support layer with one or more insulating layers and/or one or more index matching layers deposited on the supporting layer (step  402  of process  400 ). For example, the supporting layer provided can be supporting layer  242  illustrated in  FIG. 2A . As another example, as illustrated in  FIG. 5A , the die  502 A can include a supporting layer  542 , insulating layer  513 , index matching layer  515 , and insulating layer  517  deposited on the supporting layer  542 . The supporting layer  542  and index matching layer  515  can include, but are not limited to including, silicon. The supporting layer  542  can, additionally or alternatively, include a material having certain properties for integrating components on one or both sides of the supporting layer. The components integrated on the side(s) of the supporting layer can include, but are not limited to, microlens arrays, optical traces, multiplexers, and the like. 
     In some examples, the light emitter (e.g., light emitter  207  illustrated in  FIG. 2A ) can be formed and/or placed in the supporting layer (e.g., supporting layer  242 ) prior to the layers (e.g., layers  210 ) being deposited. As one example, the supporting layer can be etched to form a cavity, the light source (included in the light emitter) can be placed into the cavity, the supporting layer can be etched again to form waveguides, and the layers can be deposited on top. 
     In some examples, the supporting layer  542  and the index matching layer  515  can form a waveguide for light to propagate. For example, the light from the light emitter (e.g., light emitter  207  illustrated in  FIG. 2A ) can propagate through the waveguide formed by supporting layer  542  and index matching layer  515 . The insulating layer  513  and the insulating layer  517  can include, but are not limited to, SiO 2 . One or more pockets (e.g., pocket  512  illustrated in  FIG. 5B ) can be formed in the supporting layer/insulating layer/index matching layer stackup (step  404  of process  400 ). The pocket(s) can be formed by using one or more etching techniques such as wet etching, dry etching, or the like. In some examples, forming the pocket  512  can include removing the insulating layer  513  such that the supporting layer  542  is exposed (i.e., not covered by insulating layer  513 ). In this manner, an etalon-free (e.g., a broadband etalon-free) outcoupler can be subsequently formed. 
     An outcoupler material (e.g., outcoupler material  515  illustrated in  FIG. 5C ) can be grown in the pocket(s) (e.g., pocket  512  illustrated in  FIG. 5B ) (step  406  of process  400 ). The outcoupler material  515  can be grown using any number of growth or deposition techniques such as a chemical vapor deposition (CVD), molecular beam epitaxy (MBE), atomic layer deposition (ALD), sputtering, and the like. The outcoupler material  515  can be any material that matches the refractive index of the supporting layer  542 . An exemplary material includes, but is not limited to, amorphous silicon. 
       FIGS. 5C-5D  illustrate cross-sectional and top views, respectively, of an exemplary die after outcoupler material is formed in the pockets according to examples of the disclosure. The outcoupler material  515  can be formed in the pockets of the die  502 A. Although the examples of the disclosure may discuss the process flow for forming the edge outcoupler and the device using a single die, examples of the disclosure are applicable to processes for forming multiple dies on a single wafer.  FIG. 5E  illustrates a top view of an exemplary wafer having multiple dies according to examples of the disclosure. The wafer  504  can include multiple dies, such as die  502 A and  502 B. The multiple dies can be formed from the same wafer  504  and can undergo the same processing steps at the same time. For example, the outcoupler material  515  can be deposited in multiple pockets, one or more of which may belong to different dies than others. As shown in the figure, the wafer  504  can include a plurality of dice lanes  505 . The dice lanes can be locations designated for dicing. In this manner, one or more steps of the process can be completed prior to dicing. The dicing step can occur at any step in the process. Additionally, examples of the disclosure are not limited to separating all of the dies via the dicing step. For example, half of the wafer may be separated (e.g., dicing along a horizontal dice lane) after step  404 . The top half of the wafer may undergo separate processes (e.g., polishing the outcoupler at a 45-degree angle) than the bottom half (e.g., polishing the outcoupler at a 50-degree angle). Dies included in the top half of the wafer may then be separated (e.g., via dicing along a vertical dice lane) after a subsequent step. 
     In some examples, outcouplers can be located along multiple edges of a given die. For example, although  FIG. 5E  illustrates die  502 A as including outcouplers located on the right edge of the die, examples of the disclosure can include outcouplers additionally located on other edges such as the top, left, and/or bottom edges. In some examples, a die may have different shapes and different number of edges, where outcouplers can be located on any number of the edges. For example, a die that has a pentagon shape can include any or all of the five edges having outcouplers, a die that has a hexagon shape can include any or all of the six edges having outcouplers, etc. 
     One or more additional layers may be deposited on top of the outcoupler material, as shown in  FIG. 5F  (step  408  of process  400 ). The additional layers can include one or more insulating layers, one or more conductive layers, one or more index matching layers, one or more encapsulation layers, one or more passivation layers, one or more planarizing layers, or the like. The layers will be collectively referred to as layers  510 . 
     The dies can be diced along the dice lanes (e.g., dice lanes  505  illustrated in  FIG. 5E ), and one or more edges of one or more dies can be polished.  FIG. 5G  illustrates a cross-sectional view of an exemplary die having a polished edge according to examples of the disclosure. The polishing step can lead to removal of some of the outcoupler material to form the outcoupler  509  included in die  502 A (step  410  of process  400 ). In some instances, the polishing step can also lead to removal of some of the layers  510 . 
     In some examples, the polishing step can include polishing the outcoupler material along a targeted polish plane such that the targeted polish depth and/or polish angle is achieved, as discussed below. In some instances, the characteristics of the targeted polish plane can be based on the location of the emission region (e.g., emission region  282  illustrated in  FIG. 2A ), the location of the detection regions (e.g., detection regions  256  illustrated in  FIG. 2A ), the path length of the light (discussed below), and/or the sample properties to be measured. One example targeted polish depth can be 10 μm, although examples of the disclosure are not limited to such. One example targeted polish angle can be 45 degrees or 54.7 degrees, although examples of the disclosure are not limited to such angles. 
     In some examples, more than one edge of a die can be polished. In some examples, a single edge of a die can include multiple outcouplers (as shown in  FIG. 5D ). The multiple outcouplers along the same edge can have the same targeted polish plane. In some instances, two or more of the outcouplers along the same edge can have different targeted polish planes. 
     A reflective material can optionally be deposited on the outcoupler  509  to form a reflector  511  (step  412  of process  400 ). A plurality of bonding bumps  536  can be formed on the layers  510  (step  414  of process  400 ).  FIGS. 5H-5J  illustrate cross-sectional, top, and planar views, respectively, of the die  502 A after the bonding bumps are formed on the layers according to examples of the disclosure. 
     In some examples, the die can include a plurality of outcouplers, as illustrated in the top and planar views of  FIGS. 5I-5J , respectively. For example, die  502 A can include outcouplers  509  and outcoupler  519 . The outcouplers included in a single die can have different properties (e.g., materials, size, shape, polish angle, etc.). In some instances, one type of outcoupler (e.g., outcoupler  509 ) can be configured for one type of measurement (e.g., the measurement involving light that interacts with the measured sample volume), and another type of outcoupler (e.g., outcoupler  519 ) can be configured for another type of measurement (e.g., the measurement involving a reference detector used to account for drift in the optical components such as the light emitter). 
     Although the above figures illustrate the bonding bumps formed after separating the dies via a dicing step, examples of the disclosure can include separating the dies after the bonding bumps are formed on the layers. As illustrated in the top view shown in  FIG. 5K , the wafer  504  can include a plurality of dies, such as die  502 A and die  502 B. The bonding bumps  536  can be formed on the plurality of dies prior to dicing along the dicing lanes  505 . In some examples, after the dies are separated via the dicing step, one or more encapsulation layers can be deposited over the bonding bumps to maintain the integrity of the bonding bumps during the step of polishing the outcoupler(s). 
     The die can be flipped over and bonded to an interposer (e.g., interposer  241  illustrated in  FIG. 2A ) (step  416  of process  400 ). One or more optics (e.g., optics  219  illustrated in  FIG. 2A ) and layers (e.g., layers  219  illustrated in  FIG. 2A ) may be formed on the top (e.g., closest to the system interface) side of the supporting layer (e.g., supporting layer  242  illustrated in  FIG. 2A ) (step  418  of process  400 ). In some examples, the optics can be one or more microlenses formed by etching the supporting layer. The thermal slug(s) (e.g., thermal slug  232  illustrated in  FIG. 2A ) may be bonded to the supporting layer (e.g., supporting layer  242  illustrated in  FIG. 2A ) using one or more solder connections (e.g., solder connection  234  illustrated in  FIG. 2A ) (step  420  of process  400 ). The detector array (e.g., detector array  230  illustrated in  FIG. 2A ) may be placed on top of the layers (e.g., layers  219  illustrated in  FIG. 2A ) (step  422  of process  400 ). The thermal slug may also be bonded to the windows (e.g., windows  201  illustrated in  FIG. 2A ) using a thermally conductive epoxy (not shown) (step  424  of process  400 ). The frame (e.g., frame  214  illustrated in  FIG. 2A ) may be bonded to the supporting layer (e.g., supporting layer  242  illustrated in  FIG. 2A ) and a hermetical seal can be created (step  426  of process  400 ). 
     Examples of the disclosure further include using one or more fiducials in the polishing step (e.g., step  410  illustrated in  FIG. 4 ) for control of the depth and angle of the polished edge(s) of the outcoupler(s).  FIGS. 6A-6B  illustrate cross-sectional and top views, respectively, of the fiducials included in the layers of an integrated photonics device according to examples of the disclosure. The die  602 A can include a plurality of fiducials  623 . The fiducials  623  can allow a given target polish plane  621  to be achieved during the polishing step. One or more fiducials may not be visible until a given amount material has been removed. For example, in polishing the layers  610 , the fiducial  623 A can become visible once a certain amount of layer  610 A is polished. If the target polish depth is deeper, the polishing step can continue to remove a given amount of material from layer  610 B until the fiducial  623 B becomes visible, and so on. 
     The fiducials  623  can be included in the layers, where the number and depth from the topmost layer can be based on the target polish depth. For example, if the target polish depth is located at 5 um, and layer  610 D is also at 5 um, then the exposure of the fiducial  623 E would be an indication that the target polish depth has been reached. 
     Additionally, the fiducials can have certain horizontal locations based on the target polish angle. For example, the ends of the fiducials  623  can form a plane that is angled at the given target polish angle. If the target polish angle changes, the horizontal offset of the fiducials can be changed accordingly. Generally, a smaller offset can be used for steeper target polish angles. In some examples, the fiducials  623  may have one edge that is vertically aligned, but may have another edge that is not (e.g., the fiducials  623  may not be the same length). 
     The fiducials  623  can be made of any material that is at least partially opaque and can be included in the layers  610 . An exemplary material is metal. The fiducials  623  can be arranged, shaped, and/or sized according to a given target polish plane  621 .  FIG. 6B  illustrates fiducials  623  that are rectangular, and  FIG. 6C  illustrates fiducials that are triangular. Additionally, examples of the disclosure can include two or more fiducials that have different sizes, shapes, materials, or other properties. For example, as shown in  FIG. 6B , the fiducials  623  can be different lengths. In some instances, the die can include multiple sets of fiducials. For example, one set of fiducials can be located at multiple corners of a square or rectangular die. The sets of fiducials can be the same, or in some instances, may be oriented differently. For example, one set of fiducials can include triangles whose vertex is oriented in one direction, and another set of fiducials can include triangles whose base is oriented in the same direction. 
     A method for operating the device to determine one or more properties of a sample is now discussed.  FIG. 7A  illustrates an exemplary device and  FIG. 7B  illustrates an exemplary method for determining the properties of a sample according to examples of the disclosure. The device  700  can have one or more components and/or functions similar to those discussed above in the context of device  200 , device  300 , and/or process  400 . A controller (not shown) can send one or more signals through an interposer  741 , bonding bumps  736 , and one or more layers  710  to a light emitter  707  (step  752  of process  750 ). The one or more signals from the controller can cause the light emitter  707  to emit light. Light from the light emitter  707  can propagate through the waveguide created by layers  710  to the outcoupler  709  (step  754  of process  750 ). The outcoupler  709  can redirect the light  751  towards the emission optics  791 . Before, during, and/or after, a thermal slug  732  can allow heat from one or more optical components (e.g., the light emitter  707 ) to be transferred via one or more heat transfer paths  755  to the system interface  790 . 
     The emission optics  791  can direct, collimate, and/or focus light  751  towards the emission region  782  and through window  701  (step  760  of process  750 ). Light  751  can undergo a scattering event at location  759  of the measured sample volume  720  (step  762  of process  750 ). At the scattering event, the light can return to the device  700  as light  753 . Light  753  can transmit through window  701 . The detection optics  716  can direct, collimate, and/or focus light  753  towards the detector array  730  (step  764  of process  750 ). The detector pixels in the detector array  730  can generate a plurality of signals indicative of the detected light, and layers  719  can route the signals to a controller or a processor for processing (step  766  of process  750 ). The signals can be routed out of the hermetically sealed enclosure to another board (e.g., board  243  illustrated in  FIG. 2A ). 
     In some examples, at least one of the outcouplers can be configured for redirecting light (i.e., a reference light beam) to a reference detector. The reference detector can be used to reduce the amount of drift from the light emitter that is included in the measurement signal(s). For example, the outcoupler  519  illustrated in  FIG. 5J  can be a reference outcoupler configured for redirecting light to a reference detector. The light emitted by the light emitter(s) can be split using an optical splitter, for example, where a certain percentage of the emitted light can be directed at the reference outcoupler. The reference outcoupler can direct the light to a reference detector, without directing the light to optics (e.g., optics  291  and/or optics  216  illustrated in  FIG. 2A ), an emission region (e.g., emission region  282  illustrated in  FIG. 2A ), or detection regions (e.g., detection regions  256  illustrated in  FIG. 2A ). In some examples, the detector array (e.g., detector array  230 ) can include a reference detector (not shown), which can have its active area oriented towards the reference outcoupler. In some instances, the active area of the reference detector can be oriented in a different direction than the active areas of the remainder detectors. In some examples, a reflector can be included in the device in the optical path of the reference light beam to direct the light from the reference outcoupler to the reference detector. 
     Representative applications of methods and apparatus according to the present disclosure are described in this section. These examples are being provided solely to add context and aid in the understanding of the described examples. It will thus be apparent to one skilled in the art that the described examples may be practiced without some or all of the specific details. Other applications are possible, such that the following examples should not be taken as limiting. 
     An integrated photonics device is disclosed. The integrated photonics device can include: a supporting layer including a first side and a second side; one or more windows located at a system interface of the integrated photonics device; optics configured to redirect, focus, and/or collimate incident light to or from the one or more windows; one or more edge outcouplers configured to redirect light towards at least some of the optics; one or more light emitters configured to emit light in response to first signals, where the emitted light is incident on the one or more edge outcouplers; a plurality of first layers deposited on the first side of the supporting layer, wherein the plurality of first layers is configured to route the first signals from a controller to the one or more light emitters; one or more detectors configured to detect return light and generate second signals indicative of the detected return light, wherein the detected return light includes at least a portion of the emitted light; a plurality of second layers deposited on the second side of the supporting layer, wherein the plurality of second layers is configured to route second signals from the one or more detectors to the controller or a processor; and the controller or a processor configured to determine one or more sample properties based on the second signals. Additionally or alternatively, in some examples, the integrated photonics device further comprises: a frame connected to the supporting layer, wherein the frame is configured to create a hermetic seal around at least the one or more detectors and at least some of the optics. Additionally or alternatively, in some examples, the integrated photonics device further comprises: one or more traces electrically connected to the one or more second layers, wherein the one or more traces are configured to route the second signals to a location outside of the hermetic seal. Additionally or alternatively, in some examples, the integrated photonics device of claim  1 , further comprises one or more thermal slugs configured to relocate heat from one location to another, the one or more thermal slugs thermally coupled to the supporting layer and the one or more windows. Additionally or alternatively, in some examples, the one or more thermal slugs are located around the one or more optics. Additionally or alternatively, in some examples, the integrated photonics device further comprises: one or more solder connections configured to connect the one or more thermal slugs to the supporting layer, wherein the one or more solder connections are located in locations corresponding to the one or more light emitters. Additionally or alternatively, in some examples, the one or more edge outcouplers includes an outcoupler material, the outcoupler material including amorphous silicon, the supporting layer includes silicon, and the plurality of first layers includes silicon and silicon dioxide. Additionally or alternatively, in some examples, the plurality of first layers includes one or more of insulating layer(s) and conductive layer(s), at least some of the plurality of first layers including a plurality of fiducials, wherein at least two of the plurality of fiducials are offset relative to one another, the offset based on a target polishing plane. Additionally or alternatively, in some examples, the integrated photonics device further comprises: a plurality of second fiducials, wherein the plurality of second fiducials is oriented along a different direction than the plurality of fiducials. Additionally or alternatively, in some examples, the optics are one-layer optics. 
     A method for determining one or more properties of a sample using an integrated photonics device is disclosed. The method can comprise: emitting light from one or more light emitters towards one or more waveguides; propagating the emitted light using the one or more waveguides to one or more edge outcouplers, the one or more waveguides formed from at least some of a plurality of first layers; redirecting the emitted light using the one or more edge outcouplers towards optics; redirecting, focusing, and/or collimating the redirected light using the optics towards one or more windows of the integrated photonics device; receiving return light from the one or more windows by one or more detectors; generating second signals indicative of the return light using the one or more detectors; and determining the one or more properties of the sample based on the second signals. Additionally or alternatively, in some examples, the method further comprises: creating a hermetic seal around at least the one or more detectors and the one or more windows. Additionally or alternatively, in some examples, the method further comprises: routing the second signals from the one or more detectors to a controller located outside of the hermetic seal. Additionally or alternatively, in some examples, the method further comprises: routing first signals from a controller using one or more of an interposer and bonding bumps; and transmitting first signals to the one or more light emitters, the first signals associated with the emitted light from the one or more light emitters. Additionally or alternatively, in some examples, the method further comprises: relocating heat from the one or more light emitters to the one or more windows using one or more thermal slugs. 
     A method for forming an integrated photonics device is disclosed. The method can comprise: providing a wafer, the wafer including a supporting layer and a plurality of first layers on a first side of the supporting layer; and forming one or more integrated edge outcouplers including: forming one or more pockets by etching the plurality of first layers, growing outcoupler material in the one or more pockets, and polishing at least one edge of wafer along a target polish plane, wherein the polish exposes at a least a portion of the outcoupler material. Additionally or alternatively, in some examples, forming the one or more integrated edge outcouplers further comprises: depositing additional material on top of the outcoupler material prior to the polishing. Additionally or alternatively, in some examples, forming the one or more integrated edge outcouplers further comprises: depositing a plurality of fiducials in the plurality of layers such that the plurality of fiducials is offset with respect to one another to form the target polish plane. Additionally or alternatively, in some examples, the method further comprises: forming a plurality of second layers on a second side of the supporting layer; forming a detector array on the plurality of second layers; connecting a frame to the supporting layer; and creating a hermetic seal using the frame. Additionally or alternatively, in some examples, the method further comprises: forming one or more light emitters on the first side of the supporting layer; forming one or more solder connections in locations corresponding to the one or more light emitters; forming one or more thermal slugs; and thermally coupling the one or more thermal slugs to the supporting layer using the one or more solder connections. 
     Although the disclosed examples have been fully described with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art. Such changes and modifications are to be understood as being included within the scope of the disclosed examples as defined by the appended claims.