Design of a fiber-optic interrogator module for telecommunication satellites

Abstract

Abstract-In this paper we present the results of the radiation tests performed on the optical components of the fiber-optic interrogator module as a part of the Hybrid Sensor Bus (HSB) system. The HSB-system is developed in the frame of an ESA-ARTES program and will be verified as flight demonstrator onboard the German Heinrich Hertz satellite in 2016. The HSB system is based on a modular concept which includes sensor interrogation modules based on I²C electrical and fiber Bragg grating (FBG) fiber-optical sensor elements. Onboard fiber-optic sensing allows the implementation of novel control and monitoring methods. For read-out of multiple FBG sensors, a design based on a tunable laser diode as well as a design based on a spectrometer is considered.The expected and tested total ionizing dose (TID) applicable to the HSB system is in the range between 100 krad and 300 krad inside the satellite in the geostationary orbit over a life time of 15 years. We present radiation test results carried out on critical optical components to be used in the fiber-optic interrogation module. These components are a modulated grating Y-branch (MGY) tunable laser diode acting as light source for the tuning laser approach, the line detector of a spectrometer, photodetectors and the FBG sensors acting as sensor elements. A detailed literature inquiry of radiation effects on optical fibers and FBG sensors, is also included in the paper.The fiber-optic interrogator module implemented in the HSB system is based on the most suitable technology, which sustains the harsh environment in the geostationary orbit.

High-resolution wavelength tuning technique for a widely tunable MG-Y lasers

“…As the core element of the scanning laser interrogator for an optical fiber Bragg grating (FBG) sensor system, it has been used in a wide range of research and a wavelength resolution of about 1 pm and precision of about 2 pm has been achieved [8,9]. However, this performance does not completely satisfy the requirements of high-precision interrogators, and the performance of the MG-Y laser may degrade due to environmental changes, cosmic radiation, etc [10][11][12]. This degradation effect will lead to a tuned wavelength drift and resuts in interrogator accuracy deterioration.…”