Rapid-calibration optical tunable delay line on 3-µm-thick SOI photonic platforms

Optical tunable delay lines (OTDLs) which can capture temporal optical signals, and overcome the challenge of halting light are crucial for optical communications and microwave photonics. Here, a rapid-calibration 8-bit OTDL on the 3-µm-thick silicon-on-insulator (SOI) platform consisting of waveguide spirals and integrated optical switches is proposed, achieving a maximum delay time of 3570 ps with a resolution of 14 ps/stage. The large delay is attributed to the spirals of a 3-µm-thick SOI platform featuring a delay efficiency of approximately 11.49 ps/mm, with wavelength-insensitivity transmission loss of 0.32 dB/cm, and the polarization-dependent loss is only 0.075 dB/cm within 140 nm bandwidth. In addition, the optical switches with extinction ratios up to 50 dB. Integrated variable optical attenuators can suppress crosstalk and facilitate rapid calibration for OTDLs. The advantages of OTDLs' large delay time, high signal-to-noise, and rapid calibration make them suitable for optical programmers and microwave photonics radars.