High performance and highly reliable lambda /4 shifted MQW-DFB-DC-PBH-LDs for Gb/s coherent optical communication systems

The authors demonstrate high-performance and highly reliable single-frequency quarter-wave ( lambda /4)-shifted multiple-quantum-well distributed-feedback laser diodes with double-channel planar buried heterostructure (MQW-DFB-DC-PBH LDs). Superior characteristics, such as narrow spectral linewidth (about 1 MHz) and flat FM response (several GHz bandwidth with less than 50-kHz dip frequency) at high light output power, have been obtained with small values of coupling coefficient and cavity length product ( kappa L), and thick separate-confinement-heterostructure (SCH) layers. An estimated lifetime in terms of spectral linewidth, FM response, and lasing wavelength of over 10/sup 5/ has been obtained, demonstrating that these devices are suitable for practical use in gigabit/second coherent optical fiber communication systems.<
>