Study On The InP-Based Semiconductor Laser Diode With Multimode Interfermeter Waveguide

Semiconductor laser diode plays an important role in high speed optical transmission system. Laser diode with high output power, small size, broad wavelength width is always used as Raman and Erbium-doped fiber-amplifier pumping sources. In this paper, we design and fabricate high power LDs with multimode interferometer (MMI) waveguide.Firstly, we simulate the transmission of the optical field in the MMI. Based on the self-image principle, LD with cascaded 1×1 rectangle MMI is designed and fabricated. Because of its broad pump area, the output power is up to 21.8mW, the saturation current is about 600mA, the resistance is 3.3QΩ.Secondly, we also fabricate LDs with tapered and cascaded MMI. Compared to the LD with cascaded rectangle MMI, it has shorter MMI length while has larger pump area. Its output power is up to 32mW, the saturation current is about 780mA, and the resistance is only 1.5Ω.Thirdly, we test the optical spectrum and far field characteristics of the LDs. The peak wavelength is 1.5um with 83nm 3dB pump area. Under room temperature, it shows a stable single-mode output with high injection current.