Study of dual-wavelength distributed bragg reflection semiconductor laser with high order Bragg gratings

In order to obtain an optical beat source for THz generation, a dual-wavelength distributed Bragg reflection (DBR) semiconductor laser with high order Bragg gratings (HOBGs) is designed. The DBR laser is fabricated by ultraviolet lithography technology with strip width of 100 mm, grating period of 9.5 mm and grating groove width of 1.36 mm. High power continuous-wave dual-wavelength lasing is obtained at injection current from 0.9 A to 1.2 A and the side mode suppression ratios of short wavelength mode and long wavelength mode are larger than 35 dB and 39 dB, respectively. The 3 dB spectrum full width at half maximum of the two wavelength modes are both 0.04 nm. The wavelength difference of two lasing modes is larger than 0.58 nm, which is appropriate for an optical beat source for THz generation. When the injection current is 1.2 A, the output power of HOBGs DBR laser is up to 88 mW from one cavity facet. A kind of high power dual-wavelength HOBGs DBR laser is propsed, which provides a new solution for dual-wavelength semiconductor laser to mass production.