Dynamic range extension for heterodyne fibre-optic hydrophone by using instantaneous frequency-tracking method

This letter proposes a novel dynamic range extension method using an instantaneous frequency (IF)-tracking method for heterodyne fibre optic hydrophones (FOHs). IFs are used to compensate for large signal amplitudes in the demodulator. Theoretical analysis and simulation prove the effectiveness of the proposed algorithm. Simulation results achieve at least 19.76 dB dynamic range improvement, demonstrating great potential for extending FOHs for hydroacoustic detection and communication applications. This letter proposes an instantaneous frequency-tracking method to extend the dynamic range for heterodyne fibre optic hydrophones (FOHs). They are used directly to compensate for large signal amplitudes. The working principle is discussed, and simulations are conducted. The simulations achieve at least 19.76 dB dynamic range improvement.image