Research efforts aimed at exploring the feasibility of implementing an optical cross-connect switch using the star-coupler-based frequency-division-multiplex technique are discussed. Two specific tunable receivers have been implanted. The first is a heterodyne receiver with a tunable laser as the local oscillator (LO) and the second is a tunable filter followed by a direct-detection receiver. In the system demonstrations four frequency-locked transmitters with monolithic tunable lasers were used, each dithered with a slightly different frequency for the dual purpose of frequency locking (to a reference low-finesse fiber Fabry-Perot (FP) frequency comb) and positive channel identification upon signal reception. In the heterodyne receiver, the tunable LO was a monolithic three-section multiple-quantum-well distributed Bragg laser capable of a 1000-GHz tuning range. Receiver sensitivity was measured to be -38 dBm at 1 Gb/s (BER = 10-10). The power margin in the system substantiated feasibility for a 400 × 400 switch. In the tunable-filter receiver, the tunable filter is a tunable two-stage fiber FP filter design consisting of a narrowband filter followed by a wideband filter. The tuning of the filters is computer controlled, and the combined filter has a tuning range of 15,000 GHz with a finesse of ≈5170. Therefore, it is capable of covering over 1000 channels of 2.9 GHz each.
ASJC Scopus subject areas
- Computer Networks and Communications
- Electrical and Electronic Engineering