An analog modulation and demodulation method employing LVDT signal conditioner for fiber-optic interferometric sensors

Abstract

An analog method to modulate and demodulate fiber-optic interferometric sensors employing a linear variable differential transformer signal conditioner to generate sine modulation wave and demodulate phase-modulated signal from the photodetector’s output is presented in this letter. No external lock-in amplifiers or digital components are used in this design. All the necessary components for signal processing are integrated in a single analog electronic microchip AD698, which reduces the system’s complexity significantly. After implementation on an interferometric fiber-optic gyroscope as an example, this method demonstrates a bias stability of 0.063 deg h−1 (i.e. 0.220 µrad).

A low cost all-digital demodulation method for fiber-optic interferometric sensors

“…A low cost analog scheme, which has been proposed by our group in 2017, is presented in [16]. We used AD698 to demodulate FOISs and reduced the system's complexity significantly while increasing electronic reliability.…”