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We report on a novel design for a colorless wavelength adding-and-dropping module. The module comprises a cyclic demultiplexer and an optical cross connect and greatly reduces the insertion loss of this functionality, in comparison to other approaches. Implementation of ultralow-power-consumption thermo-optic switches simplifies the module thermal control.

A novel tunable dispersion compensator (TDC) with /spl plusmn/500-ps/nm tuning range and bandwidth support for 40-Gb/s signals is described. The TDC is constructed from a waveguide grating router (WGR) that provides very high spatial dispersion and a deformable cylindrical mirror for applying quadratic spatial phase across the dispersed wavefront. The WGR's 100-GHz free-spectral range (FSR) allows the device to simultaneously apply the same dispersion to all wavelength-division multiplexing (WDM) channels.

A novel device that demodulates both quadratures of the optical differential quadrature phase-shift keying (DQPSK) format in a single interferometer by using a 4 /spl times/ 4 star coupler was demonstrated. Simultaneous measurements of both DQPSK quadratures at 42.7 Gb/s are also presented.

A compact and simple silica-waveguide 10-Gb/s tunable optical dispersion compensator (ODC) that works with uncontrolled wavelength transmitters by tracking the signal wavelength is demonstrated. Transmissions at 10.7 Gb/s over 5100 ps/nm of dispersion with a duobinary signal using a single pass of the ODC and 3825 ps/nm of dispersion with an unchirped non-return-to-zero signal using a double pass of the ODC are shown.

This paper describes the demonstration of an improved eight-channel coarse wavelength-division multiplexer. The fully packaged channel losses range from 2.3 to 3.9 dB, the 1-dB bandwidth is 16.3 nm, and the crosstalk is

We integrated a wavelength-selective cross-connect, de-interleaver, interleaver, power combiner, and variable attenuators on one silica waveguide chip and a band demultiplexer, band multiplexer, and optical monitor on another. These two chips are used to create an eight-channel add-drop node that is expandable up to 80 channels with minimal traffic interruption by adding more of these chips.

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.