Performance Characteristics of Buried Facet Quarter-wave Shifted Distributed Feedback Lasers.
01 January 1989
The performance characteristics of quarter-wave shifted distributed feedback lasers emitting near 1.3microns are described. The quarter-wave shifted grating is fabricated on substrate using the double exposure holographic technique. These lasers are of the etched mesa buried heterostructure type with a semi- insulating Fe: InP layer for carrier and optical confinement. The low reflectivity required for this quarter-wave shifted DFB laser is obtained using buried facets at both ends of the laser, whose effect is verified by the distribution of the sub-threshold spectrum. The lasers have threshold current of 30mA, external differential quantum efficiency of 0.18 mW/mA/facet, bandwidth of 11.5GHz at 10mW and 10 dB chirp width of 2.5angstroms under 40mA modulation current at 5 Gb/s.