Design for single-mode asymmetric quarter-wavelength-shifted DFB laser with high differential efficiency

Abstract

An asymmetric quarter-wavelength-shifted DFB laser which has high differential efficiency and a large threshold gain difference under high-power operation has been designed taking the spatial hole-burning effect into account. The optimum kL was found to be about 1.4 in the laser, which has an asymmetry S/L of 0.15, where S is the distance from the centre to the phase shift position and L is the laser length.