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arXiv · 2504.11965

Mode locking via delayed orthogonal-polarization reinjection in semiconductor VCSELs

T. Wang·Y. Ma·Z. Li·Y. Li·Z. Tu·Y. Zhang·G. Xu·S. Baland·S. Xiang·Y. Hao
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Abstract

We demonstrate harmonic mode-locking in a semiconductor VCSEL using polarization-controlled delayed feedback. By integrating a rotatable $\lambda$/2-plate within an external cavity, we achieve precise control over pulse multiplicity and repetition rates in TE and TM modes. For the TE mode, increasing the $\lambda$/2-plate angle ($\theta$) transitions the system from disordered quasi-periodic states to stable fundamental (single-pulse) and harmonic dual-pulse mode-locking. Polarization-resolved measurements and cross-correlation analyses reveal coherent pulse alignment at half the cavity roundtrip time, enabled by polarization-mediated nonlinear dynamics. This work establishes cross-polarization feedback as a fundamental mechanism for ultrafast pulse engineering, advancing the understanding of polarization-mediated nonlinear dynamics in laser physics.

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T. Wang, Y. Ma, Z. Li, Y. Li, Z. Tu, Y. Zhang, G. Xu, S. Baland, S. Xiang, Y. Hao. 2025-04-16. Mode locking via delayed orthogonal-polarization reinjection in semiconductor VCSELs. https://arxiv.org/abs/2504.11965

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