Method and apparatus for coupling a surface-emitting laser to an external device

Abstract

A surface emitting laser is coupled to an external modulator. The laser and the modulator aligned by photolithographically defined features. In a preferred embodiment, the electromagnetic output of the laser is reflected at a right angle from a mirror mounted on a substrate. The reflected output enters a modulator mounted on the same substrate as the mirror. A circuit coupled to the modulator controls the modulation undergone by the electromagnetic output. The modulated output is coupled to an optical fiber for transmission.

What is claimed is:  
     
         1 . A system for coupling one or more surface-emitting lasers to one or more corresponding external optical devices, the system comprising: 
 (a) the one or more surface-emitting lasers, each laser adapted to produce an electromagnetic output; and    (b) an optical bench substrate having photolithographically defined therein, for each said surface-emitting laser, a coupling mirror positioned to receive the output of a corresponding surface-emitting laser and a corresponding optical device positioned to receive the output of said surface-emitting laser from the coupling mirror.    
     
     
         2 . The system of  claim 1 , wherein the one or more surface-emitting lasers are vertical-cavity surface-emitting lasers (VCSELs).  
     
     
         3 . The system of  claim 1 , wherein the one or more surface-emitting lasers are fabricated in a laser substrate, the system further comprising said laser substrate, the laser substrate and the optical bench substrate comprising photolithographically defined alignment features for aligning said laser and optical bench substrates together so as to optically couple each of the surface-emitting lasers to corresponding optical devices mounted on said optical bench substrate via a corresponding coupling mirror.  
     
     
         4 . The system of  claim 1 , wherein said optical devices are electroabsorption optical modulators.  
     
     
         5 . The system of  claim 4 , wherein the optical bench substrate further comprises, for each said coupling mirror and corresponding optical modulator, a driver circuit coupled to the modulator.  
     
     
         6 . The system of  claim 5 , wherein the electromagnetic output is modulated at more than 1 Gb/s by the optical modulator.  
     
     
         7 . The system of  claim 4 , wherein the optical bench substrate further comprises, for each said coupling mirror and corresponding optical modulator, a semiconductor optical amplifier positioned in the path of the electromagnetic output from the corresponding optical modulator.  
     
     
         8 . The system of  claim 4 , wherein the optical modulators are edge-absorbing, edge-emitting optical modulators.  
     
     
         9 . The system of  claim 1 , wherein said optical devices are semiconductor optical amplifiers (SOAs).  
     
     
         10 . The system of  claim 1 , wherein said optical devices are optical fibers.  
     
     
         11 . The system of  claim 1 , wherein the optical bench substrate further comprises, for each said coupling mirror and corresponding optical device, an optical fiber coupled to the corresponding optical device.  
     
     
         12 . The system of  claim 11 , wherein the optical bench substrate has photolithographically defined therein, for each said coupling mirror and corresponding optical device, a V-shaped slot for positioning the optical fiber to receive the output of the corresponding optical device.  
     
     
         13 . The system of  claim 1 , wherein: 
 said optical devices are electroabsorption optical modulators;    the optical bench substrate further comprises, for each said coupling mirror and corresponding optical modulator, an optical fiber coupled to the corresponding optical modulator;    the optical bench substrate has photolithographically defined therein, for each said coupling mirror and corresponding optical modulator, a V-shaped slot for positioning the optical fiber to receive the output of the corresponding optical device; and    the system is for use in one of data communications or telecommunications.    
     
     
         14 . The system of  claim 1 , wherein each coupling mirror is a planar coupling mirror.  
     
     
         15 . The system of  claim 14 , wherein each planar coupling mirror is inclined at an angle of 45° relative to the path of the electromagnetic output from said corresponding laser.  
     
     
         16 . The system of  claim 14 , wherein the optical bench substrate comprises, for each said coupling mirror and corresponding optical device, a lens positioned between said coupling mirror and corresponding optical device for shaping and/or focusing the laser output between the coupling mirror and corresponding optical device.  
     
     
         17 . The system of  claim 1 , wherein each coupling mirror is a concave coupling mirror for reflecting and focusing the output light of a corresponding surface-emitting laser onto the corresponding optical device positioned to receive the output of said surface-emitting laser from the coupling mirror.  
     
     
         18 . The system of  claim 1 , wherein the optical bench substrate is a silicon optical bench.  
     
     
         19 . The system of  claim 1 , wherein the one or more surface-emitting lasers comprise a linearly-arranged one-dimensional array of lasers and the optical bench substrate comprises a corresponding linearly-arranged one-dimensional array of corresponding coupling mirrors and optical devices.  
     
     
         20 . The system of  claim 1 , wherein the one or more surface-emitting lasers comprise a two-dimensional array of lasers and the optical bench substrate comprises a corresponding two-dimensional array of corresponding coupling mirrors and optical devices.  
     
     
         21 . The system of  claim 1 , wherein the one or more surface-emitting lasers comprise a plurality of surface-emitting lasers, each laser adapted to produce an electromagnetic output having a unique frequency different than the frequencies of said other lasers.  
     
     
         22 . The system of  claim 1 , wherein the system is further for measuring radiation absorption by a measurement species, the system further comprising: 
 one or more sources of single mode laser radiation comprising the one or more surface-emitting lasers, respectively; and    a detector for detecting the single mode laser radiation after passage thereof through a quantity of said measurement species.    
     
     
         23 . The system of  claim 22 , wherein said laser radiation is infrared laser radiation.  
     
     
         24 . The system of  claim 23 , wherein said measurement species is a gas disposed in a measurement cell.  
     
     
         25 . The system of  claim 23 , wherein said measurement species is an unconfined gas.  
     
     
         26 . The system of  claim 23 , wherein said measurement species is one or more of human blood, a bacterial species, and a viral species.  
     
     
         27 . The system of  claim 1 , wherein said optical devices are optical fiber amplifiers.  
     
     
         28 . The system of  claim 1 , wherein each said optical device is a top mirror for its respective laser which completes a laser cavity for said laser.  
     
     
         29 . A system for coupling one or more surface-emitting lasers to one or more corresponding external optical devices, each laser adapted to produce an electromagnetic output, the system comprising an optical bench substrate having photolithographically defined therein, for each said surface-emitting laser, a coupling mirror positioned to receive the output of a corresponding surface-emitting laser and a corresponding optical device positioned to receive the output of said surface-emitting laser from the coupling mirror.  
     
     
         30 . The system of  claim 29 , wherein the one or more surface-emitting lasers are fabricated in a laser substrate, the laser substrate and the optical bench substrate comprising photolithographically defined alignment features for aligning said laser and optical bench substrates together so as to optically couple each of the surface-emitting lasers to corresponding optical devices mounted on said optical bench substrate via a corresponding coupling mirror.  
     
     
         31 . A method for coupling a surface-emitting laser to an external optical device, the method comprising the steps of: 
 (a) emitting an electromagnetic output from the laser; and    (b) reflecting the electromagnetic output from a photolithographically defined mirror in an optical bench substrate to the external optical device so as to couple the electromagnetic output into the external optical device.    
     
     
         32 . The method of  claim 31 , wherein the optical device is an optical modulator, the method comprising the further step of modulating the reflected electromagnetic output with the optical modulator.