Multiplexed Oil Level Meter Using a Thin Core Fiber Cladding Mode Exciter

This letter reports a multiplexed optical oil level meter using a thin core fiber (TCF) cladding mode exciter. Weak cladding mode reflection (<;-75 dB) was employed to probe external refractive index discontinuity at an air-oil boundary. The insertion loss of one sensor is <;3 dB. A linear relationship was evaluated between the measurement position and the absolute position during the oil-level test. System-level multiplexing capability was demonstrated and no crosstalk was found between the sensors. The system accuracy was 0.16 mm.