Scalable and reconfigurable true time delay line based on an ultra-low-loss silica waveguide

A scalable and reconfigurable on-chip optical true time delay line consisting ofMach -Zehnder interferometer (MZI) switches and delay waveguides is proposed and demonstrated with the ultra-low-loss silica waveguide platform. The MZI switches provide the reconfiguration of the light traveling paths and hence different delays. Our proposed structure can be easily scaled to an M bit delay line with a slight increase in dimensions. The footprint of our fabricated 1 bit delay line is 33 mm x 13 mm (length x width) and can provide a delay of 6.0 ps with an insertion loss of 1.2 dB at the operating wavelength of 1550 nm, while the footprint of the 4 bit delay line is 43 mm x 14 mm and can provide a discrete delay tuning from 6.0 to 90.2 ps with a delay deviation lower than 0.2 ps and a tuning response time of 0.84 ms. The insertion losses are lower than similar to 2.34 dB, and the extinction ratios are greater than 20.42 dB. The average switching power is similar to 132.6 mW. Our proposed optical true time delay lines could find applications for optical beamforming in phased array antennas. (C) 2018 Optical Society of America