Colorless tunable dispersion compensator with 400-ps/nm range integrated with a tunable noise filter

We demonstrate a colorless thermooptic-lens-based tunable dispersion compensator integrated with a tunable optical noise filter. The free-spectral range is 200 GHz, the tuning range is /spl plusmn/200 ps/nm, the transmissivity 3-dB bandwidth is >40 GHz, and the linear group delay bandwidth is >48 GHz.

I. Introduction

Forty-Gb/s systems have a high sensitivity to chromatic dispersion and, thus, can benefit significantly from a per-channel tunable dispersion compensator (TDC) [1]. Fig. 1. (a) Waveguide layout of the TDC + filter. The chip is 7.4 cm×1.2 cm. (b) and (c) Operational principle with the lens turned off and turned on strongly. The lines show the principle rays for particular wavelengths. (d) Thermooptic lens design, vertically stretched for clarity. Lens is 5.5 mm long ×350 high For sparing and network flexibility reasons, each TDC should be useable for a large number of channels, i.e., “colorless.” Bulk-optic [2]–[5], ring-resonator [6], waveguide-grating router (WGR) [7], [8], and Fourier-filter [9]colorless TDCs have been demonstrated. The WGR TDC has the advantages of using standard waveguides, a single control knob, and fast tuning ( ms). In this letter, we demonstrate a WGR-based TDC with an increased tuning range of (previously we had achieved [8]). This TDC is integrated with a tunable amplified-spontaneous emission (ASE) noise filter, added at essentially no extra cost.