Multiplexing capabilities of a solid state interrogator for spectrally encoded sensors

In this paper we propose a solid state interrogation system capable of multiplexing four spectrally encoded sensors, e.g., FBGs or EFPIs, using two Wavelength Division Multiplexing devices. One is a 40 channel DWDM channel monitor, the other a proposed four channel CWDM device. The sensors are connected to the output channels of the CWDM device in order to assign a portion of the spectrum to each sensor. The reflected spectra are then analysed using the DWDM channel monitor. By monitoring the power incident on each of the DWDM channels, the four sensor reflection spectra can be reconstructed in software and information relating to the measurand obtained Based on software simulations and previous laboratory experiments with single sensors, it is believed that this system would be capable of interrogating four FBG or EFPI sensors simultaneously at frequencies of greater than 5kHz with linear errors of less than 0.08%.