A multi-channel fiber SPR sensor based on TDM technology

Surface plasmon resonance (SPR) sensor has been widely used in biochemical reaction detection. With the development of SPR sensing, multi-channel SPR sensors have attracted attention owing to their potential application in multi-analyte detection. For fiber-based SPR sensor, due to the small size of the fiber core, it is hard to realize the multi-channel fiber SPR sensor based on the time division multiplexing (TDM) technology. Here we propose and demonstrate a multi-channel fiber SPR sensor based on the TDM technology by using the multi-core fiber. The multiple cores are multiple sensing zones, which equals to subdividing the traditional single fiber core into multiple independent sensing zones, realizing the multi-channel SPR sensing. This multi-channel SPR sensor has some advantages: it can realize multi-analyte detection simultaneously; it can compensate the ambient temperature variation, nonspecific binding and physical absorption and others; it can adjust working resonance wavelength shift range by adjusting the fiber grinding angle; it can work without resonance wavelength shift range overlapping by switching independent sensing channels. Besides that, we can add a sensing zone on the receiving fiber to construct the wavelength division multiplexing (WDM) sensing for each fiber core channel. By combining TDM and WDM technology, we can double the sensing channels.