Abstract

Low-chirp and high-speed light sources are essential for the next long-haul multi-gigabit optical-fiber transmission systems. We realized a high-performance light source by the use of a photonic-integration technique. Our light source consists of a distributed-feedback laser and an electroabsorption modulator. For good performance, it is important to use two excellent solitary devices and to integrate devices without undesirable interactions. A buried heterostructure with semi-insulated InP layers and a butt joint are key points in our devices. The buried heterostructure with semi-insulating burying layers provides good electrical isolation with high-speed response and completely stabilized lasing characteristics. The butt-joint structure allowed us to attain a high optical-coupling efficiency, about 80%. The feedback of light from the joint to the laser was estimated to be negligible. We obtained a modulation bandwidth of 10 GHz and an output power of 17 mW in the fabricated devices. Also, clear eye opening with an extinction ratio of 13 dB was obtained under 10 Gb/s nonreturn-to-zero modulation. The wavelength broadening width (FWHM) was only 0.1 Å. Photonic-integration technology made this high performance possible.

© 1990 Optical Society of America