Analysis, design, and fabrication of GaAlAs/GaAs DFB lasers with modulated stripe width structure for complete single longitudinal mode oscillation

Complete single longitudinal mode operation of a GaAlAs/GaAs distributed-feedback (DFB) laser has been accomplished by making use of a modulated stripe width (MSW) structure, which is characterized by its simple configuration and versatility, compared with equivalent schemes. The coupled-mode equations are transformed into the characteristic equation for the DFB laser with arbitrary index modulation which has a form convenient for numerical analysis. Two specific examples of the stripe width modulation, namely, stepped and symmetric linear modulations, are then analyzed by making use of the equations. Optimum design of the stripe shape is subsequently carried out by assuming a particular waveguide structure. A GaAlAs/GaAs DFB laser having stepped-width modulation was fabricated by using a double-channel planar buried heterostructure.<
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