MULTIPLE QUANTUM WELL DISTRIBUTION FEEDBACK SEMICONDUCTOR LASER

摘要

PURPOSE:To improve temperature characteristics and to do transmission in a wide temperature range by avoiding the increase of detuning volume providing a multiple quantum well with different gain peaks and keeping a difference between the gain peaks and Bragg wavelength within a predetermined range at a specified operating temperature. CONSTITUTION:A waveguide layer is provided with a diffraction grating and an active layer is comprised of a multiple quantum well. The multiple quantum well is provided with two or more different grain peaks 32 and 33. The difference between the gain peak of the longest wavelength of the multiple quantum well, lattice synchronization of diffraction grating and the Bragg wavelength 31 that is determined by the practical diffraction rate of the wave guide layer is within + or -5nm at the operating temperature of -40 deg.C. The difference between the gain peak of the shortest wavelength of the quantum well layer and the Bragg wavelength 31 is + or -5nm at the operating temperature of 85 deg.C. With this, a gain peak exists near the Bragg wavelength at any operating temperature and the increase of the detuning volume is prevented.