Single-mode properties of distributed-reflector lasers

The fundamental properties of a distributed-reflector (DR) laser, consisting of an active section and a passive distributed reflector section, are theoretically investigated. The DR laser, in principle, has the properties of high efficiency and high-power performance in dynamic-single-mode operation, thus eliminating the problems of low device efficiency in DFB (distributed-feedback) lasers and low output power in DBR (distributed Bragg reflector) lasers. The effective length of a DR including gain and loss, is introduced and is applied for the analytical determination of the lasing condition. The conditions required for dynamic-single-mode operation with one-facet output are given in terms of the propagation constant difference between the active and passive regions related to the coupling coefficient of the passive reflector. This condition is experimentally found to be attainable by utilizing a conventional fabrication process.<
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