Strongly complex coupled dfb laser series

Abstract

A two-dimensional matrix of complex coupled (gain or loss coupled) semiconductor DFB lasers is disclosed. The matrix includes several parallel branches of series lasers, each series having a plurality of lasers which are grown on the same wafer. The parallel branches are combined at either one end or both ends with either an integrated on-chip optical combiner or an external coupler to obtain a single optical output port. Each laser in the series comprises a multiple quantum well active region and a complex coupled grating having corrugations along a cavity length direction formed by periodic etching grooves through either the active region or the lossy QW region. The depth of etching is defined so as to provide a substantial insensitivity of each laser to the external feedback and random facet variations and to thereby ensure no substantial interaction between lasers in the series. Bragg wavelengths of lasers from different series interleave with each other or differ incrementally along a cavity length direction. The sub tuning wavelength range covered by one laser in the matrix falls outside of the stopbands of all other lasers which are not only in the same series but also physically close to the designated output port. The laser structure is capable of simultaneous multi-wavelength generation, and/or tunable selectable single wavelength operation, and/or reliable wavelength switching.