Construction and characterization of interferometric fiber optic gyroscope (IFOG) with erbium doped fiber amplifier (EDFA)

Gyroscopes, which sense changes on absolute angular rate and are classified into Interferometric Fiber Optic Gyroscopes (IFOG), Ring Laser Gyroscopes (RLG) and Micro- Electro-Mechanical Systems (MEMS) Gyroscopes, are critical components of the navigation systems together with accelerometers. Being dominant over other types of gyroscopes in terms of performance and cost, IFOGs have widely been used in metrology and in particular defense/aerospace industry. This paper covers the design details of both optical and electronic components of IFOG prototype, the sensing mechanism of which is based on Sagnac Phase Shift, constructed in Optics Laboratory of National Metrology Institute of TURKEY as absolute angular rate sensor. In the prototype IFOG, open-loop configuration was applied, a single mode telecommunication optical fiber and an EDFA pumped by DFB laser emitting at 1549.0 nm were used as sensing coil and broadband source, respectively. The voltage data carrying Sagnac Phase Shift was extracted by a phase tracking circuit consisting of an active RC band pass filter, an amplifier with adjustable gain and an AD630 balanced modulator chip which was operated as lock-in. For the prototype IFOG, peak to peak noise of 8 (°/h) and bias stability of 1.57 (°/h) were attained respectively. Moreover the scale factor of 13.83 (°/h)/mV was derived with deviation of 0.73%.