A wide-tuning-range optical delay line is demonstrated in high (2%) index contrast waveguides. This device integrates four-stage ring resonator all-pass filters (APFs) with cascaded fixed spiral-type delay waveguides; each fixed delay path varies in length by a factor of two from the previous stage. A 2 x 2 switch separates each fixed delay and the tunable parts of the delay line. The APF allows for continuous delay tuning. This device enables coherent switching and continuous tuning ranges up to 2.56 ns.

A wide-tuning-range optical delay line is demonstrated in high (2%) index contrast waveguides. This device integrates 4-stage ring resonator all-pass filters (APFs) with cascaded fixed spiral-type delay waveguides; each fixed delay path varies in length by a factor of 2 from the previous stage. A 2x2 switch separates each fixed delay and the tunable parts of the delay line. The APFs allow for continuous delay tuning. This device enables coherent switching and continuous tuning ranges greater than 2.56ns.

Wide-tunable-range optical delay lines are demonstrated in high index contrast waveguides. This device integrates tunable allpass filters, for continuous delay tuning, with cascaded fixed delay waveguides enabling coherent switching and tuning ranges up to 2.56ns.

We report experiments on a continuously tunable true time delay and demonstrate high resolution tuning for the first time using a multi-stage all-pass filter device implemented with Ge-doped silica planar lightwave circuits.

An endless, reset-free polarization controller implemented with planar lightwave circuits using phase shifters for tuning is proposed and demonstrated. By avoiding the need for tunable polarization mode converters, simple fabrication processes and a large range of material systems can be used, since neither the electrooptic effect nor a rotatable birefringence axis are necessary for device operation. The proof of concept is demonstrated by implementing the equivalent of a rotating waveplate using Ge-doped silica-on-silicon waveguides; and thermooptic phase shifters. The polarization controller is shown to have excellent tolerance to fabrication variations. Fast thermooptic control (on the order of 10 kHz) is achieved using high-index-contrast (4%) waveguides.