Amplitude-equalized dual-wavelength rational harmonic mode-locked fiber ring laser

We report a dual-wavelength amplitude-equalized rational harmonic mode-locked fiber laser operating at up to 40 GHz based on the technique of nonlinear polarization rotation (NPR) in a highly nonlinear fiber. A theoretical simulation shows that NPR structure can introduce a self-feedback mechanism to stabilize the two simultaneously lasing wavelengths. By carefully adjusting the polarization controllers (PCs) in the cavity, amplitude-equalized pulses at two different wavelengths have been obtained.     

Design optimization of all-optical actively mode-locked ring laser based on cross-gain modulation in a semiconductor optical amplifier

A complete and detailed model is presented that describes the main physical phenomena that occur in an actively mode-locked fiber ring laser based on cross-gain modulation in a semiconductor optical amplifier employed as both the gain medium and mode-locking element. The relationship between key laser parameters and the output pulse characteristics is numerically analyzed to provide simple design rules and derive a set of necessary operational conditions. The adoption of these rules and the satisfaction of these conditions enables the optimization of the laser performance and the generation of short and high energy mode-locked output pulses.     

Harmonic Mode-Locked Er-Doped Fiber Laser by Evanescent Field-Based MXene Ti3C2Tx (T = F,O, or OH) Saturable Absorber

MXenes, as a legendary family of 2D van der Waals nanosheets materials, are extensively studied due to their unique characteristics of broadband nonlinear optical response. In particular, MXenes have excellent nonlinear optical properties of very large nonlinear absorption coefficients and very large nonlinear refractive indexes, which have attracted people's great attentions to study the application of MXenes in photonics, electronics, and optoelectronics in recent years. However, the high-repetition-rate (HRR) ultrafast pulses are not explored based on these kinds of materials. MXene Ti₃C₂T_x saturable absorber (SA) based on micro-fiber is fabricated by optical deposition method. Here, MXene Ti₃C₂T_x SA is used to achieve 36th harmonic mode-locking with a repetition rate of 218.4 MHz, a central wavelength of 1566.9 nm, the pulse width of 850 fs, and the spectral width of 3.51 nm. The maximum average output power and pulse energy are 6.95 mW and 0.032 nJ, respectively. This research based on MXene Ti₃C₂T_x light modulator opens a bright avenue for advanced nonlinear photonics.     

Stabilization of a Mode-Locked Nd: Glass Laser by Intracavity Second-Harmonic Generation

A method is described for generating stabilized, intensity-limited pulsetrains from a mode-locked Nd:glass laser with internal second-harmonic generation.     

Characterization of the train-average time-frequency parameters inherent in the low-power picosecond optical pulses generated by the actively mode-locked semiconductor laser with an external single-mode fiber cavity

The specific approach to characterizing the train-average parameters of low-power picosecond optical pulses with the frequency chirp, arranged in high-repetition-frequency trains, in both time and frequency domains is elaborated for the important case when the semiconductor laser is matched by an external single-mode fiber cavity and operates in the active mode-locking regime. This approach involves the joint Wigner time-frequency distributions, which can be created for those pulses due to exploitation of a novel interferometric technique. Practically, the InGaAsP/InP-heterolaser generating at the wavelength 1320 nm was used during the experiments carried out and an opportunity of reconstructing the corresponding joint Wigner time-frequency distributions was successfully demonstrated.     

The Experiment Study of Two Nd~（3＋）：p－glass Rods Laser with a Q－switch／mode－locking and Amplifier

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Cr^4＋：YAG在对撞脉冲锁模的Nd：YAG激光器中实现被动锁模的研究

在理论上提出了Ｃｒ＾４＋：ＹＡＧ作为可饱和吸收体在Ｎｄ：ＹＡＧ激光器中实现被动锁模的可能性，运用速率方程组导出在强激光脉冲作用下Ｃｒ＾４＋：ＹＡＧ激发态吸收的恢复时间和饱和光强。实验上在带有抗共振环结构的接近于介稳腔的脉冲式Ｎｄ：ＹＡＧ激光器中用Ｃｒ＾４＋：ＹＡＧ作为可饱和吸收体实现被动锁模运转，得到能量１３．５ｍＪ、平均脉宽１８０ｐｓ的锁模脉冲序列。     

基于单壁碳纳米管的多波长被动锁模激光器

提出了一种基于单壁碳纳米管/聚酰亚胺复合材料薄膜和马赫-曾德尔型滤波器的多波长被动锁模掺铒光纤激光器。该环形腔掺铒光纤激光器以980nm的激光二极管作为抽运源,3.2m掺铒光纤作为增益介质,单壁碳纳米管作为可饱和吸收锁模器件。增加抽运功率到24mW时,得到中心波长为1559.3nm,3dB谱宽为1.4nm,平均输出功率为0.8mW的脉冲激光输出。然后在环形腔中,接入马赫-曾德尔型滤波器作为多波长选择器件,通过调整马赫-曾德尔型滤波器两臂光纤长度差,在室温下得到了3dB带宽内稳定的15个波长激光脉冲输出,波长间隔为0.1nm,连续0.5h观察,脉冲激光输出稳定。     

半导体可饱和吸收镜锁模光抽运垂直外腔面发射半导体激光器

介绍了半导体可饱和吸收镜锁模光抽运垂直外腔面发射半导体激光器的原理、基本结构特点、应用及设计中的主要问题,对其研究进展及未来发展趋势作了分析和总结。     

基于石墨烯的被动锁模掺铒光纤孤子激光器

报道了石墨烯作为可饱和吸收体的被动锁模掺铒光纤孤子激光器。采用环形腔结构,在抽运功率为370.4mW时,产生了重复率为3.16MHz,脉宽约为1.32ps,平均输出功率为1.07mW的锁模脉冲,其单脉冲能量为0.338nJ,并观察到激光中心波长在1556.72～1558.76nm之间可调。基于Ginzburg-Landau方程进行了数值模拟,得到的结果和实验一致。