True-time-delay element in lossy environment using EO waveguides

We investigate a photonic true time delay element in a lossy environment using electrooptic waveguides. Its principle is based on the ring resonator and the all-pass filter. In the lossy environment, it is known that the insertion loss depends on the delay time when using the conventional ring resonator. We add a by-pass waveguide to the ring resonator in order to compensate the resonant-dependent loss. As a result, we have a voltage-controlled photonic true time delay element with its insertion loss independent of the delay time.