Abstract
Acousto-optic modulator (AOM) and electro-optical modulator (EOM) are applied to realize the all-fiber current sensor with a pulsed light source. The pulsed light is realized by amplitude modulation with AOM. The reflected interferometer current sensor is constructed by the mirror and phase modulation with EOM to improve the anti-interference ability. A correlation demodulation algorithm is applied for data processing. The influence of the modulation frequency and duty cycle of AOM on the optical system is determined by modeling and experiment. The duty cycle is the main factor affecting the normalized scale factor of the system. The modulation frequency mainly affects the output amplitude of the correlation demodulation and the system signal-to-noise ratio. The frequency multiplication factor links AOM and EOM, primarily affecting the ratio error. When the frequency multiplication factor is equal to the duty cycle of AOM and it is an integer multiple of 0.1, the ratio error of the system is less than 1.8% and the sensitivity and the resolution of AFOCS are 0.01063 mV/mA and 3 mA, respectively. The measurement range of AFOCS is from 11 mA to 196.62 A, which is excellent enough to meet the practical requirements for microcurrent measurement.
Highlights
All-Fiber Optic Current Sensor.The all-fiber optic current sensor (AFOCS) can measure the current accurately based on the Faraday effect and Ampere circuital theorem [1]
According to Equation (17), the Faraday rotation angle is only related to the duty cycle of acousto-optic modulator (AOM) and has nothing to do with the frequency multiplication factor
According to Equations (16) and (17), the Faraday rotation angle is related to the frequency multiplication factor and duty cycle of AOM
Summary
AFOCS has many advantages, such as excellent insulation characteristics, simultaneous measurement of AC and DC, flexible sensor diameter, and digital output [2]. Zhang et al use laser diodes as pulsed light sources to study the loop structure with single-polarization single-mode couplers [11]. The other type is the pulsed light source generated by an acousto-optic modulator (AOM). Du et al use AOM for pulse regulation when studying the sensitivity of all-fiber optic current with recirculating loop structure [12]. These methods both adopt the polarimetric current sensor. An optical interferometer current sensor with pulsed light is constructed to suppress external interference and restrict the influence of backscattered light.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
