Communication Dans Un Congrès Année : 2024

A High Resolution Phase Shift Detection System for a Differential Multimode Fiber Refractometer

Résumé

In this work, we present a phase shift detection system to instrument a differential multimode fiber (MMF) refractometer designed for methane (CH4) detection in aqueous environments. The concentration of CH4 can typically be directly obtained by observing the variation of the transmitted optical power along a functionalized MMF using a sensitised polymeric thin film compared to a reference MMF. Here, using a lock-in amplifier and modulating the laser drive current, we propose to indirectly monitor this concentration variation via phase shift measurement of a second order filter implemented using the photo diode parasitic capacitance. We show that the sensitivity of the system can be amplified by the quality factor of the circuit compared to a first order filter. Simulations show that refractive index (RI) change down to 20 nRIU can be detected. In addition, a closed-loop approach based on delay locked-loop is designed to improve both the linearity and dynamic range.

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Dates et versions

hal-04847508 , version 1 (19-12-2024)

Identifiants

Citer

Olivier D Bernal, Ardi Rahman, Haris Apriyanto, Frederic Surre, Saroj Pullteap, et al.. A High Resolution Phase Shift Detection System for a Differential Multimode Fiber Refractometer. 2024 IEEE SENSORS, Oct 2024, Kobe, Japan. pp.1-4, ⟨10.1109/SENSORS60989.2024.10784672⟩. ⟨hal-04847508⟩
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