This paper discusses the detailed experimental investigations on the performance of interferometer based fiber optic
hydrophones with different Phase Generated Carrier (PGC) demodulation algorithms for their interrogation. The study
covers the effect on different parametric variations in the PGC implementations by comparison through Signal to Noise
And Distortion (SINAD) and Total Harmonic Distortion (THD) analysis. This paper discusses experiments on most
popular algorithms based on PGC like Arctangent, Differential Cross Multiplication (DCM) and Ameliorated PGC. A
Distributed Feed-Back Fiber Lasers (DFB-FL) based fiber optic hydrophone, with Mach-Zehnder Interferometer having
active phase modulator in reference arm and mechanism to cater polarization related intensity fading were used for the
experiments. Experiments were carried out to study the effects of various parameters like the type and configuration of
low pass filter, frequency of the modulation signal, frequency of acoustic signal etc. It is observed that all the three
factors viz. the type of low pass filter, frequency of modulating and acoustic signal plays important role in retrieving the
acoustic signal, based on the type of algorithms used and are discussed here.
We report the simulation and analytical results obtained for homogenous or bulk sensing of protein on Siliconon-
insulator strip waveguide based microring resonator. The radii of the rings considered are 5 μm and 20 μm;
the waveguide dimensions are 300 × 300 nm. A gap of (i) 200 nm and (ii) 300 nm exists between the ring and
the bus waveguide. The biomaterial is uniformly distributed over a thickness which exceeds the evanescent field
penetration depth of 150 nm. The sensitivities of the resonators are 32.5 nm/RIU and 17.5 nm/RIU (RIU - Refractive index unit) respectively.