Low-noise linear-polarization fiber laser with polarization adjusted parity-time symmetry in a linear reflection structure
doi: 10.37188/CO.EN-2026-0009
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摘要:
为了能在更简化的结构设计中实现更稳定的宇称-时间（parity-time，PT）对称，以提高光信噪比和边模抑制比，本文提出并实验验证了一种基于偏振调控PT对称的低噪声线偏振单纵模光纤激光器。该PT对称结构采用线性反射结构，由工作在慢轴上的保偏环形器、偏振控制器以及单模光纤布拉格光栅组成。当增益和损耗相等且超过耦合系数时，系统满足PT对称破缺条件，从而实现单纵模激光输出。实验结果与理论分析结果一致。激光器获得了稳定输出，其边模抑制比达到62.6 dB，光信噪比为64.32 dB，洛伦兹线宽为182.5 Hz。在4 h测试时间内，激光器的偏振度和偏振消光比分别保持在99.8%和30.8 dB以上。此外，对PT对称激光器的相对强度噪声和相位噪声进行了分析，并与其他光纤激光器和半导体激光器进行了对比，验证了PT对称激光器的低噪声特性。
Abstract:A low-noise linear-polarization single longitudinal mode (SLM) fiber laser based on polarimetric parity-time (PT) symmetry is proposed and experimentally demonstrated. PT symmetry is achieved within a linear reflection structure. When the balanced gain–loss contrast surpasses the coupling coefficient, the condition for PT-symmetry breaking is met, enabling the realization of an SLM laser. Stable laser output with a high sidemode suppression ratio (SMSR) of 62.6 dB and a high optical signal-to-noise ratio (OSNR) of 64.32 dB is realized. The Lorentz linewidth is measured as 182.5 Hz. The degree of polarization (DOP) and polarization extinction ratio (PER) of the laser remain above 99.8 % and 30.8 dB within 4 hours. Furthermore, the relative intensity noise (RIN) and phase noise of the PT-symmetric laser are analyzed and compared with those of fiber lasers and semiconductor lasers. The results demonstrate the low-noise performance of the proposed PT-symmetric laser.
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Figure 1. (a) Experimental setup. (b) Optical spectrum measurement system and delayed self-heterodyne (DSH) system. (PM-EDF: polarization-maintaining erbium-doped fiber, PM-WDM: polarization-maintaining wavelength-division multiplexer, PM-OC: polarization-maintaining optical coupler, SM-OC: single-mode optical coupler, AOM: acousto-optic modulator, PD: photodiode, SMF: single-mode fiber).
Figure 2. (a) The alignment of the real part of the eigenfrequency between the polarimetric loops when the phase delay is tuned by the variation of
$ {\theta }_{a} $ . (b) The polarization state evolution in the linear reflection structure when the gain and loss of two orthogonal polarized lights are tuned by the variation of$ {\theta }_{b} $ .
Figure 3. The experimental setup for verifying the tuning of polarization-dependent loss.
Figure 5. The optical spectra under different half-wave plate adjustments
$ {(\theta }_{b}) $ . (a) Adjustment from 0° to 45°. (b) Adjustment from 45° to 90°.
Figure 6. The evolution of the power of the two lasers at different
$ {\theta }_{b} $ .
Figure 7. The radio frequency spectra of the beat signals (a) The system is operating without PT-symmetry breaking. (b) The system is operating with PT-symmetry breaking.
Figure 8. The radio frequency spectra of the beat signals under different pump powers. Inset: SMSR evolution under different pump powers.
Figure 9. The radio frequency spectra of the beat signals within 4 hours. Inset: SMSR fluctuation.
Figure 10. Optical spectra evolution under different pump powers. Inset: OSNR evolution under different pump powers.
Figure 11. The laser output characteristics within 4 hours. (a) Optical spectra, (b) stability of the laser output power and wavelength.
Figure 12. The linewidth measurement and Lorentz fitting curve of the PT-symmetric laser.
Figure 14. RINs measurement for different lasers. (a) linear frequency scale; (b) logarithmic frequency scale.
Figure 17. (a) Optical spectra of SLM operation when the filter is tuned. The tuning range spans from
1516 nm to1575 nm, with a step size of 10 nm. (b) The tuning range extends from1548.5 nm to1551.5 nm, with a step size of 0.5 nm.Table 1. Comparison of the proposed laser with representative PT-symmetric and other SLM fiber lasers.
Type[Ref.] SMSR OSNR Linewidth Polarization Stability Noise analysis PT-symmetric[13] 47.9 dB about 60 dB 2.4 kHz NR NR No PT-symmetric[15] about 50 dB 41.9 dB 390 Hz NR NR No PT-symmetric[17] 53.2 dB about 40 dB sub-kHz NR ΔP＜0.12 dB No PT-symmetric[18] 33 dB about 60 dB 368 Hz NR NR No Conventional SLM
fiber laser[24]＜40 dB 55.74 dB 1.8 kHz NR ΔP＜0.65 dB
Δλ＜0.016 nmNo This work 62.6 dB 64.32 dB 182.5 Hz DOP:99.8%
PER:30.8 dBΔP＜0.1 dB
Δλ＜0.02 nmYes 
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[1] CHEN X CH, DAI G Y, WU S H, et al. Coherent high-spectral-resolution lidar for the measurement of the atmospheric Mie–Rayleigh–Brillouin backscatter spectrum[J]. Optics Express, 2022, 30(21): 38060-38076. doi: 10.1364/OE.471155 [2] ZHANG J J, YAO J P. Parity-time–symmetric optoelectronic oscillator[J]. Science Advances, 2018, 4(6): eaar6782. doi: 10.1126/sciadv.aar6782 [3] ZHANG J J, LI L ZH, WANG G Y, et al. Parity-time symmetry in wavelength space within a single spatial resonator[J]. Nature Communications, 2020, 11(1): 3217. doi: 10.1038/s41467-020-16705-8 [4] HU H, OXENLØWE L K. Chip-based optical frequency combs for high-capacity optical communications[J]. Nanophotonics, 2021, 10(5): 1367-1385. doi: 10.1515/nanoph-2020-0561 [5] SUN H, WU K T, ROBERTS K. Real-time measurements of a 40 Gb/s coherent system[J]. Optics Express, 2008, 16(2): 873-879. doi: 10.1364/fio.2008.fwh3 [6] HERVÁS J, RICCHIUTI A L, LI W, et al. Microwave photonics for optical sensors[J]. IEEE Journal of Selected Topics in Quantum Electronics, 2017, 23(2): 327-339. doi: 10.1109/JSTQE.2017.2651117 [7] PREDEHL K, GROSCHE G, RAUPACH S M F, et al. A 920-kilometer optical fiber link for frequency metrology at the 19th decimal place[J]. Science, 2012, 336(6080): 441-444. doi: 10.1126/science.1218442 [8] TSUKAMOTO S, LY-GAGNON D S, KATOH K, et al. Coherent demodulation of 40-Gbit/s polarization-multiplexed QPSK signals with 16-GHz spacing after 200-km transmission[C]. Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference, Optica Publishing Group, 2005: PDP29. [9] GUAN X CH, YANG CH SH, QIAO T, et al. High-efficiency sub-watt in-band-pumped single-frequency DBR Tm3+-doped germanate fiber laser at 1950 nm[J]. Optics Express, 2018, 26(6): 6817-6825. doi: 10.1364/OE.26.006817 [10] LI Y J, HUANG L G, GAO L, et al. Optically controlled tunable ultra-narrow linewidth fiber laser with Rayleigh backscattering and saturable absorption ring[J]. Optics Express, 2018, 26(21): 26896-26906. doi: 10.1364/OE.26.026896 [11] ZHANG J L, YUE CH Y, SCHINN G W, et al. Stable single-mode compound-ring erbium-doped fiber laser[J]. Journal of Lightwave Technology, 1996, 14(1): 104-109. doi: 10.1109/50.476143 [12] HAO L Y, WANG X H, JIA K P, et al. Narrow-linewidth single-polarization fiber laser using non-polarization optics[J]. Optics Letters, 2021, 46(15): 3769-3772. doi: 10.1364/OL.434307 [13] LI L ZH, CAO Y, ZHI Y Y, et al. Polarimetric parity-time symmetry in a photonic system[J]. Light: Science & Applications, 2020, 9(1): 169. [14] FAN ZH Q, ZHANG W F, QIU Q, et al. Observation of PT-symmetry in a fiber ring laser[J]. Optics Letters, 2020, 45(4): 1027-1030. doi: 10.1364/OL.381106 [15] DAI ZH, FAN ZH Q, LI P, et al. Widely wavelength-tunable parity-time symmetric single-longitudinal-mode fiber ring laser with a single physical loop[J]. Journal of Lightwave Technology, 2021, 39(7): 2151-2157. doi: 10.1109/JLT.2020.3044067 [16] FAN ZH Q, DAI ZH, QIU Q, et al. Parity-time symmetry in a single-loop photonic system[J]. Journal of Lightwave Technology, 2020, 38(15): 3866-3873. doi: 10.1109/jlt.2020.2982911 [17] DAI ZH, WANG ZH R, YAO J P. Dual-loop parity-time symmetric system with a rational loop length ratio[J]. Optics Letters, 2023, 48(1): 143-146. doi: 10.1364/OL.479154 [18] DENG ZH P, LI L ZH, ZHANG J J, et al. Single-mode narrow-linewidth fiber ring laser with SBS-assisted parity-time symmetry for mode selection[J]. Optics Express, 2022, 30(12): 20809-20819. doi: 10.1364/OE.458648 [19] LIU Y, WANG L Y, YOU Y J, et al. Single longitudinal mode parity-time symmetric Brillouin fiber laser based on lithium niobate phase modulator Sagnac loop[J]. Journal of Lightwave Technology, 2023, 41(5): 1552-1558. doi: 10.1109/JLT.2022.3224208 [20] LIU W L, WANG M G, YAO J P. Tunable microwave and sub-terahertz generation based on frequency quadrupling using a single polarization modulator[J]. Journal of Lightwave Technology, 2013, 31(10): 1636-1644. doi: 10.1109/JLT.2013.2254699 [21] ULRICH R, RASHLEIGH S C, EICKHOFF W. Bending-induced birefringence in single-mode fibers[J]. Optics Letters, 1980, 5(6): 273-275. doi: 10.1364/OL.5.000273 [22] SHI J H, GUANG D, LI SH L, et al. Phase-shifted demodulation technique with additional modulation based on a 3×3 coupler and EFA for the interrogation of fiber-optic interferometric sensors[J]. Optics Letters, 2021, 46(12): 2900-2903. doi: 10.1364/OL.420655 [23] WANG Q, SONG H Q, WANG X P, et al. Experiments and analysis of tunable monolithic 1-µm single-frequency fiber lasers with loop mirror filters[J]. Optics Communications, 2018, 410: 884-888. doi: 10.1016/j.optcom.2017.11.058 [24] HSU C H, LAI Y T, CHEN L Y, et al. Tunable and stable single-frequency fiber laser by applying Rayleigh feedback light and saturable absorber filter[J]. Optical Fiber Technology, 2023, 79: 103333. doi: 10.1016/j.yofte.2023.103333 -
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