Performance Improvement and Birefringence Investigation of Spectral Domain Optical Coherence Tomography Using a Modified Arrayed Waveguide Grating

An arrayed-waveguide grating (AWG) with its high accuracy and stability is a powerful tool for spectral analysis. We investigate its potential for spectral-domain optical coherence tomography (SD-OCT). A silicon-oxynitride-based AWG spectrometer for the 800 nm wavelength range is designed for on-chip SD-OCT systems. By removing the output waveguides of the AWG, the depth range is significantly enhanced. In addition, the effect of polarization dependency of the AWG on sensitivity roll-off is investigated and for partial polarization, a beat effect is observed in the depth ranging measurements, which leads to signal fading at specific depths.