High-power-efficiency 1.55 μm tapered InP DFB laser for optical communication

Abstract

High-power 1.55 μm semiconductor lasers are extensively utilized in long-distance optical networks, autonomous driving systems, and various other applications. Increased laser output power in these systems is advantageous for extending operational range and enhancing the signal-to-noise ratio at the receiver. With the rapid advancement of optoelectronic integration and co-packaged optics, the demand for high integration density necessitates laser sources with reduced electrical power consumption and high optical output power. This study optimizes the P-type doping profile of the InP layer in the laser diode, resulting in a reduction of the series resistance of the device from 1.68 Ω to 0.71 Ω at room temperature and a corresponding decrease in electrical power consumption from 800 mW to 580 mW. Additionally, a tapered waveguide structure is employed to enhance the output power of the laser diode. Experimental results indicate that the introduction of the tapered waveguide increases the laser output power by 77.8 % at room temperature, with no significant increase in electrical power consumption. The device achieves a maximum power conversion efficiency exceeding 50 % at low currents, surpassing previously reported values in related research. Far-field test results show that the horizontal divergence angle (FWHM) of the device is effectively reduced, with no significant deterioration in beam quality. These experimental findings provide an important foundation for the development of 1.55 μm laser diodes with high optical output power and low electrical power consumption, supporting their application in optoelectronic integration.