Space active optical cable

Abstract

A space active optical cable (SAOC) includes a cable including one or more optical fibers, and two or more electrical transceivers on opposing ends of the cable and interconnected by the cable. Each of the electrical transceivers includes an enclosure that encloses one or more light sources, one or more light detectors, and control electronics. Also included in the enclosure are a coupling medium to couple light into and out of the one or more optical fibers. The coupling medium can be reflecting surface or an on-axis mount. The enclosure provides a suitable heat propagation and electromagnetic interference (EMI) shielding, and the cable and the two or more electrical transceivers are radiation resistant. SAOC features optionally support a health check algorithm that allows trending optical performance in the absence of an optical connector and a potential surface treatment to increase nominally low emissivity of an EMI conductive surface.

What is claimed is: 
     
         1 . A space active optical cable (SAOC) comprising:
 a cable comprising one or more optical fibers; and   two or more electrical transceivers on opposing ends of the cable and interconnected by the cable, each of the electrical transceivers of the two or more electrical transceivers comprising:
 an enclosure enclosing:
 one or more light sources, one or more light detectors, and control electronics enclosed in the enclosure; and 
 a coupling medium configured to couple light into and out of the one or more optical fibers, 
 
   wherein:   the enclosure provides a suitable heat propagation and electromagnetic interference (EMI) shielding, and   the cable and the two or more electrical transceivers are radiation resistant.   
     
     
         2 . The SAOC of  claim 1 , wherein each of the electrical transceivers comprise space rated electrical interface configured to receive power and communicate signals including data, command, control, and telemetry signals. 
     
     
         3 . The SAOC of  claim 1 , wherein each light source of the one or more light sources is configured to convert a received (RX) electrical signal into light, and wherein each light detector of the one or more light detectors is configured to convert received light into an electrical signal simultaneously with conversion of the RX electrical signal. 
     
     
         4 . The SAOC of  claim 1 , wherein the coupling medium comprises a reflecting surface, wherein each of the electrical transceiver is configured to utilize a shaped reflecting surface to focus light from each light source of the one or more light sources into an optical fiber and simultaneously focus received light from an optical fiber of the one or more optical fibers into a light detector of the one or more light detectors. 
     
     
         5 . The SAOC of  claim 1 , wherein the cable, the one or more electrical transceivers are built using space-rated parts, materials, and processes, wherein the space-rated parts, materials, and processes are quality controlled for vacuum compatibility and reliability. 
     
     
         6 . The SAOC of  claim 1 , wherein the coupling medium comprises an on-axis alignment mount, wherein each light source of the one or more light sources comprises a space-qualified vertical cavity surface-emitting laser (VCSEL), and wherein space-qualified VCSEL is quality controlled for radiation resistance and reliability. 
     
     
         7 . The SAOC of  claim 1 , wherein the enclosure is processed to have a laser-charred finish using short laser pulses to increase absorption and emissivity, wherein the short laser pulses are configured to produce a charred surface that is thermally conductive. 
     
     
         8 . The SAOC of  claim 1 , wherein the coupling medium comprises a reflecting surface, and wherein the reflecting surface is enhanced by shaping and/or coating with a reflective material to improve optical coupling efficiency and to protect the reflecting surface. 
     
     
         9 . The SAOC of  claim 1 , wherein each of the electrical transceivers provides autonomous management of configuration of electrical and optical components for sustained performance in space environments, mitigating temperature and radiation affects. 
     
     
         10 . The SAOC of  claim 1 , wherein each of the electrical transceivers enables optical performance trending without optical connectors, wherein the optical performance trending is achieved using bit error rate (BER) and receiver signal strength indicator (RSSI) in a sensitive low VCSEL drive regime. 
     
     
         11 . The SAOC of  claim 10 , wherein the optical performance trending during a lifetime of the SAOC is accomplished using electrical interfaces only, in a health check (HC) configuration perceptive to optical losses, wherein the HC configuration is established with a per part optical drive level with acceptable characteristics including output signal strength and bandwidth for nominally repeatable BER and RSSI. 
     
     
         12 . A method for providing a space active optical cable (SAOC), the method comprising:
 providing a cable comprising one or more optical fibers;   providing a first electrical transceiver for coupling to a first end of the cable;   enclosing the first electrical transceiver in a first enclosure enclosing a light detector and a first reflecting surface configured to reflect a first incident light;   processing the first enclosure to provide a predetermined heat propagation and electromagnetic interference (EMI) specification and to include radiation hard components; and   providing the cable and the first electrical transceiver to be radiation resistant.   
     
     
         13 . The method of  claim 12 , further comprising:
 configuring the light detector to convert a reflected light into a transmit (TX) electrical signal, and   configuring the first reflecting surface to generate the reflected light by reflecting the first incident light from the one or more optical fibers.   
     
     
         14 . The method of  claim 12 , further comprising:
 providing a second electrical transceiver coupled to a second end of the cable; and   enclosing the second electrical transceiver in a second enclosure enclosing a light source and a second reflecting surface configured to reflect a second incident light.   
     
     
         15 . The method of  claim 14 , further comprising configuring the first electrical transceiver and the second electrical transceiver to receive power and communicate signals including data, command, control, and telemetry signals. 
     
     
         16 . The method of  claim 14 , further comprising configuring the second electrical transceiver to receive a receive (RX) electrical signal and to use the light source to generate the second incident light based on the RX electrical signal, wherein a reflecting surface of the second electrical transceiver is configured to reflect the second incident light onto the one or more optical fibers. 
     
     
         17 . The method of  claim 14 , wherein processing the first enclosure comprises providing a laser-charred finish using femtosecond laser pulses, and wherein the second enclosure is processed similar to the first enclosure. 
     
     
         18 . The method of  claim 14 , further comprising shaping the first reflecting surface and the second reflecting surface and coating with a reflective material including gold or silver to improve optical coupling efficiency. 
     
     
         19 . The method of  claim 14 , wherein providing the first electrical transceiver and the second electrical transceiver including automatic configuration algorithms including a health-check (HC) process for assessing optical performance by using electrical interfaces, by using bit error rate (BER) and a receiver signal strength indicator (RSSI) in a sensitive low drive regime. 
     
     
         20 . The method of  claim 19 , wherein the HC process comprises determining an HC configuration over a planned operational thermal environment that results in an optical signal quality below a planned operational level, wherein the optical signal quality is strong enough to avoid adverse threshold effects with an acceptable input impedance (R IN ) and bandwidth (BW) behavior, while maintaining electrical interface signal integrity margins. 
     
     
         21 . The method of  claim 20 , wherein the HC process further comprises performing repeated measurements of bit error rate (BER) and receiver signal strength indicator (RSSI) to establish performance statistics for the SAOC, the performance statistics comprising an HC-BER and an HC-RSSI statistics. 
     
     
         22 . The method of  claim 20 , wherein the HC process further comprises, in context of an integrated system, repeating HC-BER and HC-RSSI measurements to establish system performance statistics including a system HC-BER and a system HC-RSSI. 
     
     
         23 . The method of  claim 22 , wherein the HC process further comprises, through an operating life of the integrated system, measuring the BER and the RSSI and detecting optical link malfunction or degradation by comparing the measured BER and the RSSI with the system HC-BER and the system HC-RSSI. 
     
     
         24 . The method of  claim 20 , wherein the HC process is applied to generically implemented active optical cables in addition to the SAOC. 
     
     
         25 . A method of providing an active optical cable (AOC), the method comprising:
 processing an enclosure to create a charred finish using laser pulses by:
 forming a nickel layer over surfaces of the enclosure; and 
 charring the surfaces of the enclosure using femto-second laser pulses, while a power level of the femto-second laser pulses are increased sharply to a predetermined-level and reduced steeply to avoid ablating the nickel layer; and 
   using the enclosure to enclose a first electrical transceiver for coupling to a transmit (TX) end of the AOC,   wherein:   a second electrical transceiver for coupling to a receive (RX) end of the AOC is enclosed similarly,   the first electrical transceiver comprises a first optical coupler formed by a first reflector surface and a light detector, and   the second electrical transceiver comprises a second optical coupler formed by a second reflector surface and a light source.   
     
     
         26 . The method of  claim 25 , wherein the first and the second electrical transceiver enable optical performance trending without optical connectors, wherein the optical performance trending is achieved using bit error rate (BER) and receiver signal strength indicator (RSSI) in a sensitive low VCSEL drive regime. 
     
     
         27 . The method of  claim 26 , wherein the optical performance trending during a lifetime of the AOC is accomplished using electrical interfaces only, in a health check (HC) configuration perceptive to optical losses, wherein the HC configuration is established with a per part optical drive level with acceptable characteristics including output signal strength and bandwidth for nominally repeatable BER and RSSI.