Device and Method for Micro-Electro-Mechanical-System Photonic Switch

Abstract

In one embodiment, a method includes reflecting, by a first mirror of a first mirror array of a micro-electro-mechanical system (MEMS) photonic switch, an optical control beam to produce an optical control beam spot on a second mirror array of the MEMS photonic switch and cyclic dithering of the first mirror to effective enlargement of a size of the optical control beam spot. The method also includes detecting, by a first photodiode having a first location on the second mirror array, a first intensity of the optical control beam spot.

What is claimed is: 
     
         1 . A method comprising:
 reflecting, by a first mirror of a first mirror array of a micro-electro-mechanical system (MEMS) photonic switch, an optical control beam to produce an optical control beam spot on a second mirror array of the MEMS photonic switch;   cyclic dithering of the first mirror to effect an enlargement of a size of the optical control beam spot; and   detecting, by a first photodiode having a first location on the second mirror array, a first intensity of the optical control beam spot.   
     
     
         2 . The method of  claim 1 , further comprising:
 detecting, by a second photodiode having a second location on the second mirror array, a second intensity of the optical control beam spot; and   detecting, by a third photodiode having a third location on the second mirror array, a third intensity of the optical control beam spot.   
     
     
         3 . The method of  claim 2 , further comprising determining a center of the optical control beam spot in accordance with at least one location and intensity pairing of the first location and the first intensity, the second location and the second intensity, and the third location and the third intensity. 
     
     
         4 . The method of  claim 3 , further comprising:
 determining a vector between the center of the optical control beam spot and a center of a second mirror on the second mirror array; and   adjusting an angle of the first mirror in accordance with the vector.   
     
     
         5 . The method of  claim 2 , further comprising adjusting an angle of the first mirror to equalize the first intensity, the second intensity, and the third intensity. 
     
     
         6 . The method of  claim 1 , wherein the cyclic dithering of the first mirror comprises applying a fixed level of two axis orbital position modulation to the first mirror. 
     
     
         7 . The method of  claim 1 , further comprising stopping the cyclic dithering of the first mirror. 
     
     
         8 . The method of  claim 7 , further comprising:
 detecting a drift in positioning of the first mirror after the stopping of the cyclic dithering; and   restarting the cyclic dithering of the first mirror upon determining that the drift of the first mirror exceeds a threshold.   
     
     
         9 . The method of  claim 1 , further comprising performing fine precession alignment on the first mirror. 
     
     
         10 . A micro-electro-mechanical system (MEMS) photonic switch comprising:
 a first mirror array comprising a first mirror, wherein the first mirror is configured to reflect an optical control beam to produce an optical control beam spot on a second mirror array; and   the second mirror array optically coupled to the first mirror array, wherein the second mirror array comprises:
 a second mirror for reflecting the optical control beam spot, 
 a plurality of mirrors within a zone of uncertainty of the second mirror, wherein mirrors of the plurality of mirrors are configured to be locked, and 
 a plurality of photodiodes comprising a first photodiode having a first location, wherein the first photodiode is within the zone of uncertainty of the second mirror, and wherein the first photodiode is configured to detect the optical control beam spot. 
   
     
     
         11 . The MEMS photonic switch of  claim 10 , wherein the plurality of photodiodes is in an octagonal pattern. 
     
     
         12 . The MEMS photonic switch of  claim 10 , wherein photodiodes of the plurality of photodiodes within the zone of uncertainty of the second mirror are configured to detect the optical control beam spot and photodiodes outside the zone of uncertainty of the second mirror are configured to not detect the optical control beam spot. 
     
     
         13 . The MEMS photonic switch of  claim 12 , wherein the photodiodes within the zone of uncertainty of the second mirror comprise a second photodiode having a second location and a third photodiode having a third location, wherein the first photodiode is configured to detect a first intensity of the optical control beam spot, the second photodiode is configured to detect a second intensity of the optical control beam spot, and the third photodiode is configured to detect a third intensity of the optical control beam spot, and wherein an angle of the first mirror is configured to be adjusted in accordance with at least one location and intensity pairing of the first location and the first intensity, the second location and the second intensity, and the third location and the third intensity. 
     
     
         14 . The MEMS photonic switch of  claim 12 , wherein mirrors of the second mirror array have an x axis pitch and a y axis pitch, wherein an angle of the first mirror is configured to be adjusted to move the optical control beam spot by half of the x axis pitch and half of the y axis pitch. 
     
     
         15 . The MEMS photonic switch of  claim 12 , wherein the first mirror is further configured to cyclically dither to effect an enlargement of a size of the optical control beam spot. 
     
     
         16 . The MEMS photonic switch of  claim 12 , wherein the first mirror is further configured to finely precess. 
     
     
         17 . A micro-electro-mechanical system (MEMS) mirror array comprising:
 a plurality of MEMS mirrors integrated on a substrate;   a first number of photodiodes integrated on the substrate; and   a second number of photodiode lines, wherein the second number of photodiode lines is less than the first number of photodiodes.   
     
     
         18 . The MEMS mirror array of  claim 17 , wherein the substrate is silicon. 
     
     
         19 . The MEMS mirror array of  claim 17 , wherein the substrate is polymer. 
     
     
         20 . The MEMS mirror array of  claim 17 , further comprising:
 a first digitizer coupled to a first photodiode of the first number of photodiodes;   a second digitizer coupled to a second photodiode of the first number of photodiodes; and   a multiplexer coupled to the first digitizer and the second digitizer.