Ultra-High resolution tunable chip-integrated photonic delay line for THz Time-Domain Spectrometer

Generation of a compact, ultra-high-resolution tunable chip-integrated delay line is one of the greatest challenges in the modern photonics system design. It is a key building block for realizing broadband optical communication systems, phased-array antennas, photonic signal processing systems, optical coherence tomography, and THz time domain spectroscopy. In this paper, a network of low-loss optical waveguides, and efficient optical switches is proposed to achieve fs laser pulse delay with a total delay of 18.5 ps with resolution of 36 fs. The envisioned THz time domain spectrometer is being designed to target the frequency range from 0.3 THz to 30 THz with a resolution of 100 GHz. This can be realized using the proposed tunable delay line architecture.