arXiv subjects

Jiwei Gan

Publications and source records attributed to Jiwei Gan.

3 recordsLinked to original sources

arXiv2026

Passive all-optical synchronization for polarization-maintaining ultrafast fiber lasers

We have proposed and implemented for the first time to our best knowledge a passive and all-optical pulse synchronization for polarization-maintaining ultrafast fiber lasers. Specifically, the synchronization system was comprised of two independent Yb-doped and Er-doped mode-locked fiber lasers in a master-slave configuration. Master pulses were injected into the slave laser cavity consisting of a nonlinear amplifying loop mirror, which provided an effective fast intensity modulator due to the periodic introduction of nonreciprocal phase difference. As a result, robust and tight timing synchronization was achieved with a cavity mismatch tolerance of 800 $\mu$m and a relative timing jitter of 26 fs within 1-MHz bandwidth. In combination with all-polarization-maintaining structure of fiber lasers, long-term stable operation was demonstrated over 12 hours without the need of temperature stabilization and vibration isolation. The implemented synchronous laser system could find immediate applications such as pump-probe microscopy, two-color spectroscopy and nonlinear frequency mixing.

physics.optics↗

arXiv2026

Observation of spectral mode splitting in a pump-enhanced ring cavity for mid-infrared generation

We report on experimental and theoretical investigation of mode-splitting dynamics in a ring cavity under the perturbation of fractional Bragg reflection from a periodically-poled nonlinear crystal. Counterintuitively, pronounced mode splitting in the spectral domain could been observed even with a tiny intensity reflection of 0.0003. The breaking of running-wave operation in the ring-cavity configuration resulted in comparable circulating fields in forward- and counter-propagation directions, which thus dramatically reduced the enhancing factor for the resonating field. In contrast, a linear cavity with intrinsically bidirectional operation was immune to the small intra-cavity reflection. Therefore, the linear-cavity layout could provide an expedient solution for a given internal reflection to obtain more stable and higher enhancement, which was confirmed by comparative studies of mid-infrared generation based on pump-enhanced difference frequency conversion. The underlying mechanism was further modeled by numerical simulations, which agreed well with experimental results. These findings could not only shed light on the understanding of the exotic feature of concatenated optical cavities, but also provide a useful guide to practical design of enhancement cavities for cavity-based frequency conversion with periodically-poled nonlinear crystals.

physics.optics↗

arXiv2026

Controlled generation of ultrafast vector vortex beams from a mode-locked fiber laser

We report on a new class of mode-locked fiber laser that allows direct creation of ultrafast vector vortex beams at arbitrary positions on the higher-order Poincar\'{e} sphere. The on-demand generation of space-variant polarization patterns was realized by controlling geometric phases inside the laser resonator to map polarization to orbital angular momentum. Thanks to the ingenious cavity design, the required intracavity manipulation of the geometric phase imposed no disturbance on the passively mode-locked operation, thus demonstrating robust and flexible switching of vectorial modes with a 8.5-ps pulse duration. Analytical expressions were deduced to model the generated cylindrically-symmetric polarization profiles, and agreed exceedingly well with experimental observations. The presented fiber laser would constitute a compact light source for producing ultrafast pulses in high-purity structured modes, which may find broad applications in classical and quantum optics.

physics.optics↗