Broadband Spiral Optical Delay on a Silicon Nitride Platform at 1310 nm Wavelength

Abstract

AbstractOptical delay lines are vital components in integrated optics circuits and systems having numerous applications in optical sensing, beamforming networks, microwave signal processing and optical coherence tomography. In this paper, we have reported spiral optical delay lines on a silicon nitride platform having various advantages such as a wide wavelength range, low bending losses and medium core-clad index contrast. These delay lines are compact in size and covers a footprint of few mm square for a length of approximately 68 cm. Simulations were performed using finite difference method for mode studies and eigen mode expansion method to study propagation along length. Further, different losses were analysed at 1310 nm centre wavelength and an excess loss was calculated to be less than 0.08 dB over the 200 nm bandwidth and propagation loss of 0.018 dB across the length of propagation was accounted.