Work

16-channel ultrashort fiber laser coherent polarization beam combination with active spatio-temporal error control

Year: 2026

Type: article

Abstract: Coherent beam combination (CBC) has proven to be an effective approach to overcoming the power limitations of single-channel lasers. As a representative implementation of CBC, coherent polarization beam combination (CPBC) becomes increasingly complex with increasing channel count, posing challenges to combining efficiency and stability. In this paper, we demonstrate integrated phase, pointing, and delay control in a 16-channel ultrashort pulse CPBC system based on the stochastic parallel gradient descent (SPGD) algorithm, using a single photodetector as the common merit sensor for all three control functions. By integrating pointing control for compensating spatial misalignment and delay control for reducing temporal mismatch, the system exhibits a broad tunable range, rapid recovery, and good scalability. The system achieves a combining efficiency of 94 %, a near-diffraction-limited beam quality (M 2 = 1.1) and a compressed pulse duration of 487 fs. An integrated relative intensity noise of 0.4 % is obtained over the frequency range from 100 Hz to 1 MHz.

Source: Optics & Laser Technology

DOI: 10.1016/j.optlastec.2026.116556