Characterization of Optical Coupling and Back-reflection of Few Mode Fibers

The continued growth of the communications industry has caused interest in mode-division multiplexing (MDM) techniques to flourish in recent years. These techniques allow individual waveguide modes to be used as distinct channels. However, as with any versatile technique, it should be also useful and beneficial to extend its application to other areas. This work concerns itself with an initial conceptual design of a mode-division multiplexing (MDM) enabled optical sensor network that can use modes to interrogate either specific sensors or sensor subsystems, and specifically with quanitizing and optimizing the injection and detection of the signal of interest. A hypothetical test setup is demonstrated, and the major issue of back reflection burying the intended signal is addressed, analyzed, and improved. Improvements in the signal-to-background contrast ratio (SBCR) of approximately 10dB were achieved depending on fibre type and proximal face. Suggestions for extensions to further improve the SBCR as well as for applications of this system are discussed.