Design And Analysis Of Signal-crystal ZnO DFB Laser Diode

Because of its low loss, narrow linewidth, the distributed feedback laser(DFB) is one of the most important devices in the field of 10 G optical fiber internet transmission system.In this dissertation, the single crystal ZnO-based DFB laser with the center wavelength near 1550 nm was discussed.First, a two-dimensional steady state mode of the single crystal ZnO DFB laser’s resonant cavity was established. Combine with the coupled wave theory and medium planar waveguide theory, the key structure parameters of the DFB laser was calculated and single mode output condition was simulated. The influence of the grating’s duty ratio, height, width and period on the laser’s resonant wavelength peak of 1550 nm was discussed. The relationship of the different laser structures and the resonant characteristics was analyzed. And the wavelength selection correlation of different semiconductor materials was investigated. Secondly, by use of the DFB laser’s grating-order characteristics, the output characteristics of a new second-order grating resonator is designed and simulated. The side-lobe of the output wavelength was suppressed, which is very helpful to reduce the laser’s line width and ensure the steady single mode output. Furthermore, in order to reduce the damage of the single crystal ZnO during the macro-fabrication process, we proposed the using of photo-resist to fabricate the grating of the ZnO DFB laser, and the resonant characteristics were discussed.At last, the transmission system of an XFP Optical transceiver module with the designed ZnO laser used in the NRZ codes was simulated by the use of the Optisystem 7.0 software. The simulation results show up to 80km’s transmission distance, 12dB’s extinction ratio and clear and open eye diagram.