Process On Half-Ring Cavity Master Oscillator Power Amplifiers

Various laser diodes have been designed and developed for high-power,near diffraction-limit laser output in the field of optoelectronics.Master Oscillator Power Amplifiers(MOPA) are typical devices adopt by researchers for its high quality laser beam output potential.To overcome the drawback of distributed feedback laser diodes(DFB-LDs) used as the master oscillator(MO) laser,half-ring cavity is proposed as the MO for its simple fabrication process and potential to prevent interfering with each other of MO and PA. High quality of output beam,high reliability may be realized with the new designed MOPA.In this paper,we have analyzed the properties of the half-ring cavity laser with the Poisson equation,the electron and hole rate equation,the Schr(?)dinger equation and the Helmholtz equation.The threshold current of the half-ring laser was computed and the relationship between the curvature radius and the threshold current densities was analyzed. The curvature radius was set around 150μm for a low threshold current density.Meanwhile, we have solved the Helmholtz equation in the curved waveguides and analyzed the relationship between the curvature radius and the optical field-intensity of the fundamental lateral mode.A light-assisted etching method was adopted to realize vertical etching.We can control the sidewall angleθin n-type bulk GaAs by changing the operation voltage of UV-LED, and realize vertical etching along(110)—B plane in p-type bulk GaAs.Furthermore,a laser-assisted wet order-selective-etching new method is proposed,which smoothes the etched surface effectively.