Widely Tunable Semiconductor Laser Based on Digital Concatenated Grating With Multiple Phase Shifts

In this paper, we proposed a widely tunable distributed Bragg reflector (DBR) laser based on digital concatenated grating with multiple phase shifts (MPS-DCG). The MPS-DCG can provide a comblike reflectivity spectrum with flat envelop covering over 100-nm wavelength range. Static characteristics of the MPS-DCG DBR laser, including the wavelength tuning range, output power, side-mode suppression ratio (SMSR), and L-I curves, are simulated using a time-domain traveling-wave model combined with a digital filter method. Tuning range of approximately 90 nm is obtained with good SMSR. The L-I curves show that the laser threshold current is around 30 mA.