Integrated photonics module for optical projection

Abstract

Optical apparatus includes a semiconductor substrate and an edge-emitting radiation source, mounted on a surface of the substrate so as to emit optical radiation along an axis that is parallel to the surface. A reflector is fixed to the substrate in a location on the axis and is configured to reflect the optical radiation in a direction that is angled away from the surface. One or more optical elements are mounted on the substrate so as to receive and transmit the optical radiation reflected by the reflector.

1 . Optical apparatus, comprising:
 a semiconductor substrate;   an edge-emitting radiation source, mounted on a surface of the substrate so as to emit optical radiation along an axis that is parallel to the surface;   a reflector, which is fixed to the substrate in a location on the axis and is configured to reflect the optical radiation in a direction that is angled away from the surface; and   one or more optical elements, which are mounted on the substrate so as to receive and transmit the optical radiation reflected by the reflector.   
     
     
         2 . The apparatus according to  claim 1 , wherein the radiation source comprises a laser diode. 
     
     
         3 . The apparatus according to  claim 2 , wherein the laser diode has a front surface, through which the optical radiation is emitted toward the reflector, and a rear surface, and wherein the apparatus comprises a radiation sensor mounted on the substrate adjacent to the rear surface of the laser diode for monitoring an output of the laser diode. 
     
     
         4 . The apparatus according to  claim 1 , and comprising a cap, which covers the radiation source, reflector and optical elements and comprises:
 a transparent window through which the radiation exits the apparatus; and   a radiation sensor mounted in the cap adjacent to the window for monitoring an output of the apparatus.   
     
     
         5 . The apparatus according to  claim 1 , wherein the reflector comprises a reflecting surface that is etched into the substrate. 
     
     
         6 . The apparatus according to  claim 1 , wherein the substrate comprises a single crystal, and wherein the reflector comprises a reflecting surface formed by cleaving the substrate along an axis of the crystal. 
     
     
         7 . The apparatus according to  claim 1 , wherein the reflector comprises an optical surface having a profile selected to impart a desired convergence or divergence to the radiation. 
     
     
         8 . The apparatus according to  claim 7 , wherein the optical surface comprises a concave reflecting surface for increasing an angular spread of the radiation. 
     
     
         9 . The apparatus according to  claim 8 , wherein the concave reflecting surface is tilted relative to the axis, and wherein the profile has a conical shape. 
     
     
         10 . The apparatus according to  claim 7 , wherein the reflector comprises a prism having an inner reflecting surface and having entry and exit faces, such that at least one of the entry and exit faces is curved. 
     
     
         11 . The apparatus according to  claim 1 , wherein the one or more optical elements comprise a lens. 
     
     
         12 . The apparatus according to  claim 1 , wherein the one or more optical elements comprise a patterned element. 
     
     
         13 . The apparatus according to  claim 12 , wherein the patterned element comprise a diffractive optical element. 
     
     
         14 . The apparatus according to  claim 1 , wherein the reflector comprises a scanning mirror, which is configured to scan the reflected optical radiation over a predetermined angular range. 
     
     
         15 . The apparatus according to  claim 14 , wherein the scanning mirror comprises a micro-electrical mechanical system (MEMS) driver, which is mounted on the substrate at a diagonal relative to the surface on which the radiation source is mounted. 
     
     
         16 . The apparatus according to  claim 14 , wherein the optical radiation from the radiation source impinges on the scanning mirror without other optics intervening between the radiation source and the scanning mirror. 
     
     
         17 . The apparatus according to  claim 1 , wherein the radiation source comprises a plurality of edge-emitting radiation sources which are arranged together on the substrate to emit the optical radiation along multiple, respective axes. 
     
     
         18 . Optical apparatus, comprising:
 a semiconductor substrate;   a first array of surface-emitting radiation sources, which are mounted on a surface of the substrate so as to emit optical radiation along respective axes that are perpendicular to the surface; and   a second array of optical elements, which are mounted over the first array and aligned with the respective axes so that each optical element receives and transmits the optical radiation emitted by a respective radiation source.   
     
     
         19 . An imaging system, comprising:
 an illumination assembly, which is configured to project a pattern of optical radiation onto an object, and which comprises:
 a semiconductor substrate; 
 at least one radiation source, mounted on a surface of the substrate so as to emit optical radiation along an axis; and 
 optical elements, which are mounted on the substrate in alignment with the axis so as to receive and transmit the optical radiation toward the object; 
   an imaging assembly, which is configured to capture an image of the pattern on the object; and   a processor, which is configured to process the image so as to generate a depth map of the object.   
     
     
         20 . A method for producing a photonics module, comprising:
 mounting an edge-emitting radiation source on a surface of a semiconductor substrate so that the source emits optical radiation along an axis that is parallel to the surface;   fixing a reflector to the substrate in a location on the axis so as to reflect the optical radiation is a direction that is angled away from the surface; and   mounting one or more optical elements on the substrate so as to receive and transmit the optical radiation reflected by the reflector.   
     
     
         21 . The method according to  claim 20 , wherein the radiation source comprises a laser diode. 
     
     
         22 . The method according to  claim 21 , wherein the laser diode has a front surface, through which the optical radiation is emitted toward the reflector, and a rear surface, and wherein the method comprises mounting a radiation sensor on the substrate adjacent to the rear surface of the laser diode for monitoring an output of the laser diode. 
     
     
         23 . The method according to  claim 20 , and comprising:
 fitting a cap over the radiation source, reflector and optical elements, the cap comprising a transparent window through which the radiation exits the module; and   mounting a radiation sensor in the cap adjacent to the window for monitoring an output of the method.   
     
     
         24 . The method according to  claim 20 , wherein fixing the reflector comprises etching a reflecting surface into the substrate. 
     
     
         25 . The method according to  claim 20 , wherein the substrate comprises a single crystal, and wherein fixing the reflector comprises forming a reflecting surface by cleaving the substrate along an axis of the crystal. 
     
     
         26 . The method according to  claim 20 , wherein the reflector comprises an optical surface having a profile selected to impart a desired convergence or divergence to the radiation. 
     
     
         27 . The method according to  claim 20 , wherein the one or more optical elements comprise a lens. 
     
     
         28 . The method according to  claim 20 , wherein the one or more optical elements comprise a patterned element. 
     
     
         29 . The method according to  claim 20 , wherein mounting the edge-emitting radiation source and fixing the reflector comprises producing multiple optoelectronic sub-modules, comprising respective radiation sources and reflectors, on a semiconductor wafer, and
 wherein mounting the one or more optical elements comprises overlaying a wafer-level array of the optical elements on the optoelectronic sub-modules.   
     
     
         30 . The method according to  claim 29 , and comprising, after overlaying the wafer-level array, dicing the wafer and the array together to produce multiple integrated photonics modules. 
     
     
         31 . The method according to  claim 20 , wherein fixing the reflector comprises mounting a scanning mirror on the substrate, and driving the mirror to scan the reflected optical radiation over a predetermined angular range. 
     
     
         32 . The method according to  claim 20 , wherein mounting the radiation source comprises mounting a plurality of edge-emitting radiation together on the substrate so as to emit the optical radiation along multiple, respective axes.