Analysis coupling between a laser and a single—mode fiber with a ball lens based on Monte Carlo method

In order to study effect of different parameters on coupling efficiency between a semiconductor laser and a single-mode fiber with a ball lens,its optical transmission model was established.Based on ABCD matrix and the coupling theory of Gaussian beam to a single-mode fiber,its coupling efficiency was calculated.The parameter tolerances were obtained when the coupling efficiency decreased 0.5dB and the ball lens was in 0.5mm radius.Combined with coupling efficiency calculation model,the coupling efficiency distribution was simulated with Monte Carlo method when the parameters met the normal distribution.The result shows that maximum efficiency reaches 0.616 and the maximum likely efficiency is 0.585.The efficiency improves significantly as the parameters' tolerances reduce by half.But further narrowing of tolerances can't enhance the efficiency obviously.The research approach is instructive for selection of alignment units and estimation of coupling efficiency in laser device package.