Fiber Optic Filter Integration

Integration of dichroic fiber optic filters in avionics platforms provide a means for rapidly diagnosing potential problems in a cabling harness in situ. Current methods require the multiple service technicians and access to both sides of the cable. By using an out of band test wavelength from the signal source, a dichroic filter can discriminate the two wavelengths and provide a measure of the optical fiber link integrity with access to only one end of the fiber. The dichroic filter reflects the out of band signal and transmits the in band optical signal. Photon Sciences has previously demonstrated  single ended optical loss measurements, and transmission of in band 25Gb/s signal is unimpeded. In this previous work, the dichroic dielectric filters were designed and applied directly to the connectors of a fiber optic jumper cable. The integration of the filters into modern military avionics systems requires the optimization and ruggedization of the optical coatings and environmental testing. In this direct to phase II program, Photon sciences will refine the design of the filters for military readiness by refining the coating materials, and work with transceiver makers (e.g. Radiall, Ultracomm, Cinch Connectivity, etc.) to integrate the filters. For connectorized transceivers, this can be as simple as adding an appropriate jumper cable. In other transceivers, such as parallel optic interconnects, an optical fiber stub component will be coated and provided for assembly within the transceivers. The dichroic fiber filters can be made to operate with any combination of fiber types, data transmission and measurement wavelengths. To make the single ended test measurements, the fiber optic filters together with an optical multiplexer will be integrated into a fiber optic loss meter. Initially this will be an additional passive component that can be used in conjunction with current Navy approved test equipment. To make quantitative measurements, the system will also include a calibration standard fiber jumper to be measured prior to attachment to the cable under test. The ultimate goal is to provide a fully integrated test solution. Photon sciences will integrate a fiber optic loss meter, and in follow on effort may work with one of several approved vendors (e.g. Kitco, Tempo, Photonix, Exfo) to develop a fully integrated solution that is ready for field testing on aircraft. The dichroic filters can be designed to work with all types of optical fibers, and any combination of signal and measurement wavelengths. Integration of a visual fault location laser may also be included in the instrument.