Scott L. Broutin

Fully functional integrated tunable and stabilized lasers and transmitters for DWDM applications

Tunable lasers are becoming critical in DWDM systems for reasons of increased system functionality, system adaptability and costs. Key issues that arise are wavelength tuning range, characterization of the devices, wavelength control, mode stabilization, wavelength switching times, output power and long term stability of operation. We have developed tunable EML components and transmitters that address all these issues. Transmission at 2.5 Gb/sec over 640 km of fiber has been demonstrated using an EA-DBR capable of being tuned to any one of 20 wavelengths spaced at 50 GHz. These lasers are integrated into a single package with wavelength stabilization elements and can be stabilized such that both the desired wavelength and mode are maintained during operation. These integrated modules are also incorporated into a small form factor transmitter capable of operating in DWDM systems.

High-power tunable DBR lasers for digital communication systems

High power buried heterostructure 1.55micrometers tunable DBR lasers have been designed, fabricated and characterized. The laser consists of a gain section, a distributed Bragg reflector, a semiconductor optical amplifier and front photodetector for automated power control. The heterostructures were grown by MOCVD with the help of selective area growth techniques and dual waveguide heterostructure. Several advantages stem from this integration scheme which include simplicity of design and fabrication, increased reliability and low cost. The laser exhibits output power of 13dBm in the fiber and is tunable over 30(50GHz) ITU channels. The laser exhibits excellent performance and long-term control and reliability. The laser/transmitter also demonstrates significant increase of its functionality while its size remains small.