A Low Loss Silicon Photonic Switchable Optical Delay Line With Low Power Consumption

Optical delay line (ODL) featuring low power consumption and low loss are very demanding for various applications such as optical communications, optical coherence tomography, and microwave photonic signal processing, etc. In this paper, we design, fabricate, and characterize a low loss silicon photonic switchable optical delay line chip with low power consumption based on well-designed spiral thermo-optical switches (STOS) and multi-mode spiral delay waveguide (MMSDW). The proposed 5-Bit silicon ODL can achieve a maximum delay of 1535.52 ps, with an average power consumption as low as 16.29 mW, and a low optical loss delay ratio of 0.006 dB/ps. It is noteworthy that all the optical switches in the proposed ODL have an extinction ratio larger than 25 dB with a low switching power below 2.7 mW, which is almost one order of magnitude lower than other reported silicon ODL. Furthermore, a compact footprint as small as 1.7 mm × 6.6 mm is achieved by our optimized design.