Optimizing the efficiency of a laser diode and single-mode fiber coupling using multi-aspherical lenses

The continuous increase in the network access rate requires a higher integration of optoelectronic devices for optical communication. Optical devices require a longer optical path and an enhanced power budget. Therefore, this study designs a three-lens coupled optical path for integrating multiple laser diodes and photodiodes with a high coupling efficiency. The coupling efficiency between the laser diode, aspherical lenses, and single-mode fibre (SMF) is analysed using the physical ray-tracing method. In the simulation results, the maximum coupling efficiency of the system reaches 72.8% by optimising the parameters of the optical path. In the experimental results, the maximum coupling efficiency is 68.01%, indicating the effectiveness of the theoretical approach and proposed design scheme. Furthermore, the simulated results indicate that a higher coupling efficiency (79.41%) would be achieved by increasing the core diameter of the SMF under the same conditions. Additionally, using the same divergence angle of the laser diode (79.04%) or decreasing the focal length of the lens (77.24%) can achieve a higher coupling efficiency. These results provide an important reference point for the design and manufacture of laser chips and SMF.