A. Griffin

Integrated resonance-enhanced variable optical delay lines

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/spl times/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.

Bending of a planar lightwave circuit 2/spl times/2 coupler to desensitize it to wavelength, polarization, and fabrication changes

We present a planar lightwave circuit curved 2/spl times/2 coupler. Its splitting ratio has a low sensitivity to wavelength, polarization, and fabrication yet is low-loss and compact. We present simple formulae for its design. We demonstrate a 50/50 version in silica-on-silicon waveguides. We discuss the tradeoff between amplitude accuracy and phase accuracy in such densensitized couplers.

An integrated tunable chromatic dispersion compensator for 40 Gb/s NRZ and CSRZ

Periodic compensators using ring resonator allpass filters are demonstrated with tuning ranges up to 500 ps/nm and signal bandwidths of 45 to 60 GHz. System results are presented for 40 Gb/s NRZ and CSRZ.

Planar lightwave circuit based reconfigurable optical add-drop multiplexer architectures and reusable subsystem module

We describe a wide range of reconfigurable optical add-drop multiplexer architecture designs that may be implemented in standard silica-on-silicon planar lightwave circuits. This proven, reliable technology offers high performance and cost-effective solutions for reducing complex service provisioning in reconfigurable optical networks. Recent advances enable very flexible wavelength routing devices for mesh- and ring-based networks to be implemented on a common subsystem integration platform. We show excellent system performance at 10 Gb/s.

Versatile integrated PMD emulation and compensation elements

Highly versatile building blocks for polarization-mode dispersion (PMD) emulation and compensation are demonstrated using tunable all-pass filters fabricated in 4%-index-contrast planar waveguides. While the all-pass filters can approximate any phase response, the complexity in setting the individual filter parameters is minimized by restricting the all-pass filter responses to realize a range of differential delays, dispersion, and dispersion slope. A single section can approximate first-order or a higher-order PMD term or emulate chromatic or higher-order dispersion. A differential group delay (DGD) tuning range over 100 ps is demonstrated for 10 Gb/s and 25 ps for 40 Gb/s data. Second-order PMD with a tuning range of 255 ps/sup 2/ and third-order PMD with a range of 2430 ps/sup 3/ are also demonstrated. The larger index contrast required for the ring-resonator-based all-pass filters is advantageous in reducing the thermooptic response time to achieve polarization rotation speeds on the order of 0.1 /spl mu/s/degree. The device is interferometrically stable and compact in size. It can be fully integrated, scaled to many sections, and can implement a variety of PMD synthesis and statistical-emulation approaches.

Demonstration of an integrated, tunable high resolution true time delay line

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.

Ring Resonators with Polarization Diversity Using Integrated Polarization Beam Splitters

Polarization beam splitters are demonstrated in 4% index-contrast Ge-doped silica waveguides with extinction ratios exceeding 24dB over a wavelength range of 80nm. Integration with ring resonators and a double-pass, reflective architecture are also presented.

Compact integrated tunable dispersion compensators

Tunable dispersion compensators for 10 and 40 Gb/s signals using planar waveguide ring-resonator allpass filters are reviewed. Recent work using tunable ring-resonators as building blocks for PMD emulation, compensation and monitoring are also discussed.

Reconfigurable optical add-drop multiplexer (ROADM) with integrated sub-band optical cross-connect

We demonstrate a monolithic high-performance reconfigurable optical add-drop multiplexer (ROADM) with integrated 24/spl times/8 wavelength selecting optical cross-connect. Eight of the 24/spl times/100 GHz WDM channels may be dropped to any of 8 wavelength-independent drop ports.

High performance variable optical attenuator multiplexer filter (VMUX)

We report progress on fully integrated variable optical attenuator multiplexers (VMUXs). We show substantial performance improvements, notably very low loss and PDL, and the realization of extremely compact designs in high delta silica-on-silicon.