Yb^3＋—Doped Non—π—Phase—Shifted distributed Feedback Fibre Lasers

Distributed feedback (DFB) fibre lasers usually have two longitudinal modes symmetrically located at each side of the Bragg wavelength because they have the same lowest gain threshold.In order to obtain single longitudinal output,π-phase-shifted DFB fibre lasers are often adopted.However,we found that,even with no π-phase-shift,the single frequency output can be acquired from Yb^3 -doped fibre DFB lasers.The polarization beat frequency was measured to be 366MHz.     

蓝宝石激光器—90年代的激光器

1982年P.Moulton第一次在掺钛蓝宝石(Ti:Al2O3)中产生激光.此后经过六年的努力,人们解决了生长优质晶体,控制晶体的参数和器件结构设计等技术问题,到1988年底开始有了掺钛蓝宝石激光器商品.美国 Lasers & Optronics杂志推荐的1989年十项尖端产品中有两项是掺钛蓝宝石激光器,它们用连续波氩离子激光器泵浦,调谐范围大约是700-1000nm,最大输出功率可以到 2.5 W.美国光谱物理公司固体激光器产品部主任认为掺钛蓝宝石激光器将成为90年代的激光器. 在室温下掺钛蓝宝石的上能级寿命约为3.2us,比ns量级的染料的上能级寿命长得多,但比一般固体激…     

A Discharge—Excited SrBr2 Vapour Laser

A new-style discharge tube for a metal vapour laser has been designed and built.SrBr2 was successfully used to replace the metal strontium as a working medium.Multi-line laser oscillations from resonance to metastable transition of strontium atoms (6.45μm),ions (1.03μm/1.09μm) and from strontium ion recombination (416.2nm/430.5 nm)have been obtained through longitudinal pulsed discharge.The problem of an incompatibility reaction between metallic strontium and the discharge tube in the strontium vapour laser has been solved.Some proposals are presented for further developments of strontium halide lasers.     

A Step—by—Step Tunable Compound External Cavity Semiconductor Laser with Two—Side Feedback Coupling

A kind of compound external cavity semiconductor lasers(CECSL) is presented,by which laser with a discretely tunable wavelength can be obtained to meet the potential demands of the wavelength division multiplexing system.By the introduction of two-side feedback coupling in the CECSL,the CeCSL can operate more efficiently,and its side-mode suppression ratio is high up to 50dB.     

Investigation of External Optical Feedback Resistance of IC—DFB and GC—DFB Lasers Using a Very Simple Experimental set—up

We study the external optical feedback resistance of both index-coupled(IC) and gain-coupled distributed feed-back(DFB) lasers using a very simple experimental set-up.Though IC-DFB lasers with large coupling coefficients are found to be less sensitive to external reflection,they suffer from mode instability at high injection level.On the other hand ,the introduction of gain-coupling mechanism can significantly improve both the immunity of external optical feedback and the single mode yield of the device.     

He—Ne激光器粒子数反转径向分布光谱测量

用二维光学多道分析仪考察了He-Ne激光器在632.8nm激光振动和不振荡时氖能级3s_2和2p_k(k=1,2,……8,10)的侧光辐射,进行了Abel反演后,得到了3s_2和2p_k各能级粒子数和3s_2和2p_k间粒子数反转的径向分布,研究了此分布勺放电电流、632.8nm激光辐射强度间的关系,推算了在放电管中心3s_2和2p_k能级间受激辐射的激光增益。     

QJH—T50型He—Ne激光器的维修

小型内腔式He-Ne激光管一旦不出光,通常就只能报废,但对全外腔式QJH-T50型He-Ne激光器,因其价格昂贵,一般都要尽可能予以维修。我们总结出一些维修经验供同行参考。     

Intracavity—Doubled Self—Q—Switched Nd,Cr：YAG 946／473nm Microchip Laser

We carried out the operation of an intracavity frequency-doubled self-Q-switched Nd,Cr:YAG/NHbO3 946/473nm microchip laser pumped by a Ti:sapphire laser.The overall cavity length was about 4mm.The maximum average blue power of 12mW was achieved with a repetition rate of 13kHz at an absorbed pump ower of 545mW.The pulses of the 473nm laser had a duration of 7ns and a peak power of 132W at this pump level.The conversion efficiency was 2.2% with respect to the absorbed pump power of a 808nm laser.     

频率分裂与模竞争现象教学实验He—Ne激光器

一、引言激光课程中,激光的频率特性和激光烧孔效应及模竞争这两部分内容都是必需但又较难理解的内容,因而辅助教学的实验就显得尤为重要。通常进行激光频率特性实验的装置是扫描干涉仪。实验方法是让激光束射入扫描干涉仪,在示波屏上观察激光纵模。学生所能做的仅是学习如何使用扫描干涉仪和激光束含有几个纵模的感性认识。学生无法控制这些纵模(频率)以及纵模间隔。实验的质和量相对于纵模(频率)这一概念的重要性来说,显得不够充实。     

InGaAsP—InP大光腔结构激光器

本文针对影响InGaAsP-InP激光器温度特性的各种因素,设计并制备了大光腔(LOC)结构激光器.实验表明,这种结构改善了激光器的温度稳定性,获得了低阈值(宽接触型器件J_(th)≈2.5kA/cm~2),高功率(脉冲输出3W)和高特征温度(T_o=150K)器件.     

Performance of the Self—Q—Switched Cr,Yb：YAG Laser

We report on the spectral properties of Cr,Yb:YAG crystal co-doped with 0.025 at.% Cr and 10 at.% Yb are reported.Using a continuous wave Ti:sapphire laser as a pumping source,we have demonstrated the self-Q-switched Cr,Yb:YAG laser at room temperature.We obtained an average output power as much as 75mW at 1.03μm with a pulse width (FWHM)as short as 0.4μs.The laser experiment demonstrated that the Cr,Yb:YAG crystal exactly combines the Cr^4 saturable absorber and Yb^3 gain medium.The Cr,Yb:YAG crystal can be a most promising self-Q-switched laser crystal for compact and efficient solid-state lasers.     

Generalized synchronization of chaos in erbium—doped dual—ring lasers

We investigate chaotic synchronization in the generalized sense in unidirectionally coupled erbium-doped fibre dual-ring lasers. Numerical simulation shows that no matter whether the two different erbium-doped fibre dual-ring lasers are chaotic or not before coupling, they show generalized synchronization with a suitable unidirectional coupling coefficient under which the maximum condition Lyapunov exponent is negative. We also use the auxiliary system approach to detect the generalized synchronization.     

小功率He——Ne激光管模式的研究

本文通过对三只激光管模式的测定,阐述共焦球面扫描干涉仪的基本原理,对获得的实验数据进行计算研究,分析得出三个激光管中三号激光器综合质量最好。     

选支CO—CO_2复合激光器的研究

本文首次报道了一种新型的室温封闭的选支CO-CO_2复合激光器及其工作特性.从5.2～6.3μm和9.2～10.8μm.光谱区获得近二百条激光谱线,强线功率分别达2.5W(CO)和10W(CO_2).并讨论了复合激光器中CO和CO_2分子的激发过程.     

Optical Pulse Generation with Different Repetition Rates in a Dual—Wavelength Actively Mode—Locked Fibre Ring Laser

We propose a simple configuration for dual-wavelength operation in an actively mode-locked fibre ring laser with fibre Bragg gratings.We experimentally demonstrate simultaneously mode-locked operation with two wavelengths at different repetition rates:one is harmonically mode-locked and the other is rational harmonically mode-locked.     

Controlling hyperchaos in erbium—doped fibre laser

The dual-ring erbium-doped fibre laser shows a hyperchaotic behaviour under some conditions.The hyperchaotic behaviour can be well controlled to enter into periodicity by modulating the pumping in one of the two rings.The period is different for different modulation index at the same modulation frequency,or for different modulation frequency at the same modulation index.