MULTIWAVELENGTH DFB LASER ARRAY TRANSMITTERS FOR ONTC RECONFIGURABLE OPTICAL NETWORK TESTBED

We discuss the design, fabrication, and performance of experimental mu ltiwavelength laser array transmitters that have been used in the reco nfigurable optical network testbed for the Optical Network Technology Consortium (ONTC), The experimental four-node multiwavelength network testbed is SONET/ATM compatible. It has employed multiwavelength DFB l aser arrays with 4 nm wavelength spacing for the first time, The testb ed has demonstrated that multiwavelength DFB laser arrays are indeed p ractical and reproducible, For the DFB laser arrays used in such a net work the precise wavelength spacing in the array and the absolute wave length control are the most challenging tasks, We have obtained wavele ngth accuracy better than +/-0.35 nm for all lasers, with some registe red to better than +/-0.2 nm, We have also studied the array yield of our devices and used wavelength redundancy to improve the array yield. Coupling efficiencies between -2.1 to -4.5 dB for each wavelength cha nnel have been obtained, It is, achieved by using specially designed l ensed fiber arrays placed on a silicon V-grooved substrate to exactly match the laser spacing, The transmitter consisted of a multichip modu le containing a DFB laser array, an eight-channel driver array based o n GaAs IC's, and associated RF circuitry.