Defocuser for compact free space communication

Abstract

Methods, devices, and systems are described for free space optical communication. An example device can comprise a defocuser configured to receive an optical signal from a laser and control a beam divergence of the optical signal. The device can comprise a controller configured to cause the defocuser to adjust the beam divergence based on an operational mode of the laser.

What is claimed: 
     
         1 . A device for free space optical communication comprising:
 a defocuser configured to receive an optical signal from a laser and control a beam divergence of the optical signal; and   a controller configured to cause the defocuser to adjust the beam divergence to a first beam divergence for a first operational mode and a second beam divergence greater than the first beam divergence for a second operational mode, and wherein a first aperture is used for the first operational mode and the second operational mode.   
     
     
         2 . The device of  claim 1 , further comprising a second aperture used for a third operational mode. 
     
     
         3 . The device of  claim 1 , wherein the defocuser comprises an adjustable lens, and wherein the controller is configured to cause the defocuser to adjust the beam divergence based on one or more of adjusting a shape of the adjustable lens or adjusting a position of the adjustable lens. 
     
     
         4 . The device of  claim 1 , wherein the first aperture is configured to transmit and receive optical signals to one or more communication devices. 
     
     
         5 . The device of  claim 1 , wherein the controller is configured to provide forward error correction and framing of a data payload of the optical signal. 
     
     
         6 . The device of  claim 1 , wherein the controller is configured to control one or more beam steering mirrors and operate control loops for narrow-field-of-view operation and wide-field-of-view operation. 
     
     
         7 . The device of  claim 1 , further comprising Micro-Electro-Mechanical Systems (MEMS) mirrors configured for operation in both the first operational mode and the second operational mode. 
     
     
         8 . A method for free space optical communication comprising:
 adjusting, based on a change from a first operational mode to a second operational mode, a defocuser from a first setting that causes a first beam divergence to a second setting that causes a second beam divergence;   modifying, using the adjusted defocuser, a beam divergence of an optical signal; and   outputting the modified optical signal, wherein a first aperture is used for the first operational mode and the second operational mode.   
     
     
         9 . The method of  claim 8 , further comprising using a second aperture for a third operational mode. 
     
     
         10 . The method of  claim 8 , wherein the defocuser comprises an adjustable lens, and wherein adjusting the defocuser is based on one or more of adjusting a shape of the adjustable lens or adjusting a position of the adjustable lens. 
     
     
         11 . The method of  claim 8 , wherein the first aperture is configured to transmit and receive optical signals to one or more communication devices. 
     
     
         12 . The method of  claim 8 , further comprising providing forward error correction and framing of a data payload of the optical signal. 
     
     
         13 . The method of  claim 8 , further comprising controlling one or more beam steering mirrors and operating control loops for narrow-field-of-view operation and wide-field-of-view operation. 
     
     
         14 . The method of  claim 8 , further comprising adjusting Micro-Electro-Mechanical Systems (MEMS) mirrors for operation in both the first operational mode and the second operational mode. 
     
     
         15 . A system for free space optical communication comprising:
 a first optical terminal; and   a second optical terminal configured to communicate with the first optical terminal, wherein the second optical terminal comprises:
 a defocuser configured to receive an optical signal from a laser; and 
 a controller configured to adjust the defocuser to cause a first beam divergence for a first operational mode and a second beam divergence for a second operational mode, wherein a first aperture of the second optical terminal is used for the first operational mode and the second operational mode. 
   
     
     
         16 . The system of  claim 15 , wherein the second optical terminal comprises a second aperture used for a third operational mode. 
     
     
         17 . The system of  claim 15 , wherein the defocuser comprises an adjustable lens, and wherein the controller is configured to adjust the defocuser to cause the second beam divergence based on one or more of adjusting a shape of the adjustable lens or adjusting a position of the adjustable lens. 
     
     
         18 . The system of  claim 15 , wherein the first aperture is configured to transmit and receive optical signals to one or more communication devices. 
     
     
         19 . The system of  claim 15 , wherein the controller is configured to provide forward error correction and framing of a data payload of the optical signal. 
     
     
         20 . The system of  claim 15 , wherein the controller is configured to control one or more beam steering mirrors and operate control loops for narrow-field-of-view operation and wide-field-of-view operation.