A space-borne fiber-optic interrogator module based on narrow-band tunable laser diode for temperature monitoring in telecommunication satellites

In this paper measurement results of the fiber-optic interrogator module for telecommunication ‎satellite applications are presented. The sensor interrogator features from fiber ‎Bragg grating (FBG) based sensing. Benefits are intrinsic sensor distribution capability and the ‎possibility to embed optical fibers in composite structures like tanks and satellite panels. ‎ The fiber-optic interrogator module is based on a narrow-band monolithic laser diode where the ‎output wavelength is spectrally tuned by electric control signals. By evaluating the intensities of the ‎sensor response, the peak of the FBG can be monitored. The correct evaluation of the sensor ‎response is a challenging task, therefore different computational methods are presented, namely ‎centroid, finite impulse response filter and curve fitting algorithms. The algorithms shall met the ‎performance requirements in terms of measurement accuracy, robustness against laser degradation ‎and measurement rate. Furthermore the algorithms shall be implemented in an FPGA, which means ‎a detailed point of view to fixed-point arithmetic and necessary amount of hardware resources at ‎constant performance. ‎ Measurement results based on the different FBG evaluation algorithms are presented and traded ‎regarding accuracy robustness and their possible implementation in an FPGA.