一种新型主动锁模光纤激光器腔长稳定技术研究

提出了一种全新的主动锁模光纤激光器的腔长稳定方案,通过波长的变化检测腔长的漂移,使用波长锁定器得到偏移误差信号补偿腔长变化.实验得到了脉宽为7.6 ps的近变换极限锁模脉冲,其超模抑制比达到60 dB,并且在近2 h的工作时间内工作稳定,波长漂移小于0.01 nm.与已有的方案相比较,不但输出脉冲质量高、并可长时间稳定工作,而且由于采用了低成本的稳定方案,更易于实现.     

主动锁模光纤激光器的孤子理论分析

系统考虑了光纤激光器腔构参数与锁模脉冲参数的制约关系,建立了完整形式的振幅调制主动锁模光纤激光器的稳态方程;据此方程分析了主动锁模光纤激光器腔参数对锁模孤子脉冲参数的影响;分析了无啁啾孤子脉冲形成条件。     

全光纤主动锁模2 μm掺铥脉冲激光器

报道了全光纤结构主动锁模掺铥脉冲激光器,中心波长为1950 nm。利用电光相位调制器对光纤激光器进行腔内相位调制,获得了重复频率为11.884 MHz的主动锁模脉冲输出,脉宽为816 ps。改变泵浦功率、调制信号的频率和幅度,获得了重复频率为4~18 kHz的弛豫振荡调制稳定脉冲输出。锁模和弛豫振荡调制获得的输出脉冲能量波动低于7%。     

基于石墨烯的全光纤主动锁模激光器

利用光纤倏逝波耦合效应,设计了一种基于石墨烯全光纤结构的主动锁模激光器。该石墨烯全光纤锁模器件基于侧面腐蚀的单模光纤,构建了银/聚二甲基硅氧烷（PDMS）/石墨烯的电容型结构,腐蚀的单模光纤置于PDMS和石墨烯之间。实验结果显示,在电容结构两端施加与激光腔的共振频率一致及其整数倍的周期性方波电压信号,并对腔内光进行调制,可实现1558 nm光纤激光器的主动锁模。所设计的主动锁模激光器获得了基本频率及二次谐波的锁模脉冲,重复频率分别为12.2 MHz和24.4 MHz,实现了电控重复频率的脉冲输出。这种石墨烯全光纤锁模器件具有低成本、低功耗的优势,为实现灵活可控的主动锁模激光器提供了新思路。     

高信噪比多波长2 μm主动锁模光纤激光器

介绍一种多波长掺铥主动锁模光纤激光器,增益介质为长2 m的掺铥光纤,主动锁模通过铌酸锂强度调制器实现。腔内加入基于双折射的光学滤波器,利用保偏光纤双折射滤波效应在滤除腔内多余超模噪声的同时,还可以实现多波长输出。基频下的锁模脉冲频谱信噪比可达68.48 dB,在稳定的锁模状态下波长信道数最大为5。此外,腔内偏振无关隔离器被替换为偏振相关隔离器后,将锁模脉冲加载数字信号同步调制,测得的眼图光信噪比提高了8.67 dB。测试结果表明,锁模脉冲的时间稳定性得到有效提升。     

注入噪声对光纤激光器锁模启动的影响

 从掺镱光纤激光器腔内的激光场出发，讨论了掺镱光纤激光器腔内的噪声信号对锁模启动的影响，并针对我们设计的8字腔超短脉冲光纤激光器进行了研究。通过对激光器腔内锁模过程的分析发现：在泵浦功率为214.75 mW时，自行研制的8字形腔掺Yb³⁺光纤激光器在未注入噪声信号时，输出端在30～50 s内获得稳定的锁模脉冲激光输出；在腔内注入脉宽30 ns，频率10 kHz，平均功率0.2 mW的脉冲噪声后，输出端在1~2 s内获得同样稳定的锁模脉冲激光输出。实验结果表明，注入激光器谐振腔内一定的噪声信号，可加速锁模的启动。     

谐波锁模掺铒光纤激光器的稳定性研究

对谐波锁模掺铒光纤激光器的稳定性进行了实验研究.采用再生锁模技术控制腔长变化对稳定性的影响,提出了在腔内利用缠绕光纤法替代保偏光纤以获取偏振稳定机制的方案,并进行了相关实验.利用自相位调制＋频谱滤波抑制超模噪音,实验中当抽运功率在50 mW以上时就足可以抑制超模噪音.实验结果表明:采用以上三种措施能够较好地解决影响谐波锁模光纤激光器稳定的温漂、偏振起伏和超模噪音问题,从而大大提高了谐波锁模光纤激光器的稳定性.     

大色散稳定腔长的光纤锁模激光器的锁模特性研究

报道了一种新型的采用大色散腔结构的光纤锁模激光器,它可以有效地克服激光器腔长抖动对锁模的不良影响,同时,实验中发现,该结构对超模噪声也有很好的抑制作用。完成了大色散控制,电光调制器调制的,稳定的光纤锁模激光器实验,得到形状为sech^2的光脉冲输出,脉冲宽度为7.6ps,脉冲带宽积为0．335。     

连续调谐多波长主动锁模光纤激光器

利用色散补偿法纤增加腔内色散和改变调制频率,在主动锁模光纤环形激光器实验中,得到了可连续调谐的双波长激光脉冲,冷却掺铒光纤,实现了17波长的激光。     

303MHz高重复频率掺Er光纤飞秒激光器

高重复频率掺Er光纤飞秒激光器在光学频率梳、超高速光学采样等领域具有很重要的作用. 本文采用非线性偏振旋转锁模机理, 在掺Er光纤飞秒激光器中实现了重复频率为303 MHz的锁模脉冲输出. 通过优化腔内色散, 激光器腔内色散在零色散附近偏负值, 锁模后工作在展宽脉冲锁模状态. 在817 mW抽运功率下, 激光器在连续光状态下可以输出125 mW的平均功率, 在锁模状态下可以输出69 mW的平均功率, 脉冲宽度为90 fs. 当抽运功率处于700-817 mW时, 激光器可以实现自启动锁模. 激光器重复频率在5 h内的漂移量为30 Hz.     

An Experimental Study on the Output Properties of an Actively Mode-locked Er~(3 ) Doped Fiber Ring Laser

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Performance study and assessment of phase noise suppression by incoherent addition in a mode-locked fiber laser system

This paper investigates the effectiveness of phase noise suppression by incoherent addition in a passively mode-locked fiber laser. Incoherent addition is achieved by using an interferometer external to the mode-locked laser. Two different types of interferometers, Mach–Zehnder and ring, are investigated experimentally for different background phase noise levels. Measurements show that both types of interferometers can achieve good phase noise reduction for a background phase noise level above ? 130 dBc/Hz. Effects of dispersion management and pulse train intensity ratio in the interferometers are also discussed. Multi-stage cascaded interferometers are proposed for supermode noise suppression of harmonically actively mode-locked lasers.     

Multiwavelength actively mode-locked fiber ring laser with a dispersion compensated cavity

A multiwavelength actively mode-locked fiber ring laser that utilises a single semiconductor optical amplifier as both a gain and mode-locking element is presented. It is verified experimentally that the number of mode-locked wavelengths may be maximised by compensating for the anomalous intra-cavity dispersion. This is achieved through the inclusion of an appropriate length of normal dispersion fiber in the laser cavity. Using this technique, the number of wavelengths simultaneously mode-locked at 10 GHz was increased from 2 to 5.     

Radio frequency interrogated actively mode-locked fiber ring laser for sensing application

This paper proposes an actively mode-locked fiber ring laser for sensing applications. Mode-locking of the laser is achieved by driving an electro-optic amplitude modulator at an RF corresponding to the fundamental beat frequency between the longitudinal modes. The change of the cavity length produces a frequency comb around the beat frequencies. The frequency separation of the comb is found to be linearly proportional to the cavity length change. The sensing mechanism of the device is shown. Temperature measurement is demonstrated using the proposed actively mode-locked fiber ring laser.     

Generation of 10-GHz ultra-short pulses with low time jitter in an actively mode-locked fiber laser

We have experimentally achieved the 8.3-ps ultra-short pulse at 10 GHz repetition rate with the time jitter as low as 590 fs in an actively mode-locked fiber ring laser. The ring-cavity laser is mode-locked by a semiconductor optical amplifier based on cross-gain modulation. The external CW source is modulated with radio frequency signal by an amplitude modulator as the external optical pulses and, then, injected into the fiber ring cavity to achieve active mode locking. Further investigating the laser output characteristics, it indicates that the linewidth of employed CW source affects properties of the generated ultra-short pulse, such as phase noise and time jitter. Ultra-short pulse at high repetition rate with low time jitter can be generated by the optimization of CW laser source.     

Timing Jitter in Amplitude Modulated Harmonically Mode-Locked Er-Doped Fiber Ring Lasers

The phase noise and the amplitude noise of optical pulses from the amplitude modulated harmonically mode-locked (AM-HML) Er-doped fiber (EDF) ring laser was investigated by measuring the power spectra of the optical pulses. The root mean square (RMS) timing jitter and the RMS amplitude noise are 1.26 ps and 2.5% (500 Hz-50 kHz), respectively, when the pulse repetition frequency is 1.58 GHz. They are smaller than those in conventional harmonically mode-locked EDF ring lasers.     

10GHz可调谐主动锁模光纤激光器

主动锁模光纤激光器研制的难点在于克服不稳定性,本文提出解决其长期和短期不稳定的方法,分析了它们的工作原理,通过试验证明该两项技术使主动锁模光纤激光器实现了自稳定运转,在全部采用国产非保偏光纤的条件下稳定运行时间超过8h,激光器重复频率为10GHz,脉宽10ps,谱宽为0.317nm,时间带宽积为0.403,调谐范围为39nm。     

8字形主被动锁模掺Er3+光纤激光器

在理论上分析了利用非线性光学环形镜作为等效可饱和吸收体压缩脉冲进行锁模的物理机制。利用8字形主被动混合锁模的结构在调制频率2．498749GHz下，在1．543μm处获得了12ps的锁模脉冲输出，对应谱宽0．22nm，时间脉宽积0．33。在抽运功率50mW情况下，输出脉冲平均功率3．715mW。在调制频率2．499344GHz、2．499114GHz和2．498999GHz时分别并获得了2～4阶幅度较为均衡的有理数谐波锁模脉冲序列。