Photonics Research, Volume. 9, Issue 4, 530(2021)
Observation of transition between multimode Q-switching and spatiotemporal mode locking
Fig. 1. Schematic of the multimode fiber cavity setup. SPDM, short-pass dichroic mirror; L1 and L2, collimating lens; M, reflective mirror; HWP, half-wave plate; QWP, quarter-wave plate; PBS, polarized beam splitter; ISO, isolator; and SF, spectral filter.
Fig. 2. (a), (b) Typical steady multimode QS pulse train generated in the MMF cavity. (a) QS pulse train with a repetition of 70.14 kHz. The inset shows the corresponding pulse width of 1.88 μs. (b) Corresponding RF spectrum of the QS state (resolution bandwidth: 10 Hz). Left inset: beam profile; right inset: RF spectrum from 0 to 500 kHz. (c) QS output power and (d) repetition rate versus pump power ranging from 6.0 W to 8.0 W. Error bars in (d) shows the repetition rate variation range of the QS pulses.
Fig. 3. Characterization of the multimode QS state using (a)–(c) spatial sampling and (d), (e) spectral filtering. (a) Spectra measured at three different points of the output beam by spatial sampling, which are visualized and marked in (c). (b) Corresponding temporal signals (from top to bottom are pulse trains detected at points A, B, and C, respectively, as indicated by their colors). (d) Spectra of the filtered output beam, showing different spectral components. (e) Corresponding beam profiles of the spectral filtered output light.
Fig. 4. Transition between QS and STML versus pump power changes. (a) Spectra of the laser output with increasing pump power, covering the CW, QS, and ML operating regimes. (b) Corresponding beam pattern with respect to four different pump power levels, as shown in
Fig. 5. Typical multimode QS–ML bistable state, shown in
Get Citation
Copy Citation Text
Kewei Liu, Xiaosheng Xiao, Changxi Yang, "Observation of transition between multimode Q-switching and spatiotemporal mode locking," Photonics Res. 9, 530 (2021)
Category: Lasers and Laser Optics
Received: Dec. 6, 2020
Accepted: Feb. 2, 2021
Published Online: Apr. 6, 2021
The Author Email: Xiaosheng Xiao (xsxiao@bupt.edu.cn), Changxi Yang (cxyang@tsinghua.edu.cn)