An apodized DFB semiconductor laser realized by varying duty cycle of sampling Bragg grating and reconstruction-equivalent-chirp technology

An apodized DFB semiconductor laser based on reconstruction-equivalent-chirp (REC) technology is proposed and investigated numerically. By changing the duty cycle of the sampling period, the magnitude of the equivalent index modulation is varied. Thus the equivalent apodization is introduced instead of an actual apodization. This novel DFB structure is advantageous in that it can enlarge the threshold gain difference and improve the mode stability compared with the conventional DFB laser. Moreover, the structure can be easily fabricated by standard holographic technology instead of high cost Electron-beam lithography.