声光锁模倍频器

改进后的激光器的激光腔内装有相当简单的单个元件,用以同时完成锁模和倍频激光输出。适当激励单个元件的非线性晶体铌酸钡钠(BSN),就能完成声光损耗调制和锁模激光输出。此外,本文还叙述了晶体在激光谐振腔内的放法。     

声光锁模器最佳驻波频率的恒温控制

测量了自制的声光锁模器最佳驻波频率随温度变化的规律,变化速度约为8.0千赫/℃。以此为依据,研制了微型恒温炉和控温电路,保证了声光主动锁模Ar~ 激光器能稳定地运转5小时以上。     

声光Q开关和锁模器件的电输入特性

本文介绍声光Q开关和锁模器件电输入的测量方法和测量结果,并作了简单分析。 声光器件的电输入端表现为复阻抗特性。通过测量声光器件的电输入特性,可对其工作频宽、压电换能器带宽,电功率反射、     

固体声光锁模器

本文简要介绍声光锁模器的基本原理和设计重点,研制了喇曼-奈斯型和布喇格型两种器件,在激光锁模中获得了良好的使用。     

声光锁模射频驱动电源

射频驱动电源是声光锁模技术的重要组成部分。本文扼要叙述了该电源的设计原则及实现设计的方法。     

磷酸盐声光主动锁模振荡器

本文报导磷酸盐玻璃声光主动锁模振荡器的实验结果。谐振腔采用腔长约为1.5米的半共焦结构,以石英玻璃为声介质,铌酸锂为换能器,调制频率为51.636兆赫。工作物质直径为10毫米、长为230毫米的磷酸盐钕玻璃,双灯泵浦,灯光脉宽300微秒,腔内插入直径2毫米的小孔,可得到单横模输出。用双光子荧光方法,测得了脉冲底宽为200微微秒左右,用F-P测得的光谱宽度     

声光主动锁模氩离子激光器

采用声光调制,以AM方式对氩离子激光器进行了主动锁模实验,观测到由锁模作用产生的激光超短脉冲序列.实测脉宽为800微微秒,重复频率为103兆周.此外还分别观测了调制深度和失谐度的影响.实验结果与有关理论计算较好地一致.     

稳定连续YAG声光锁模激光器

本文报导的是一台使用稳流电源，铟钢座结构的连续YAG激光器，采用调制频率为47．d兆赫的声光调制器作为内腔损耗调制，获得微微秒连续光脉冲的输出。脉冲宽度小于210PS，输出功率大于500毫瓦，脉冲幅度起伏为士5%。     

磷酸盐玻璃声光主动锁模振荡器

以石英玻璃为声介质,铅酸锂为换能器,调制频率为51.636兆赫.工作物质直径为10毫米、长230毫米的磷酸盐钕玻璃棒.双灯双椭圆腔,灯光脉宽为300微秒.腔长约为1.5米,腔内播入直径2毫米     

锁模激光器的声光腔倒空特性

资料[1]中实现了用锁模激光脉冲进行光学取样。本文使用同样的技术观察声光调制器进行腔倒空的激光输出中所出现的调制。资料[2～4]中证明了声光调制器作为激光腔倒空的一种手段的优越性。当腔光允许两次通过声盒时,每次都要衍射一部分光。当两束衍射光束一致并偏离腔时,它们就可用作腔倒空激光器的输出。然而由于声光调     

声光偏转器的调制传递特性

利用调制传递函数(MTF)分析了声光偏转器的分辨率。建立了高斯光瞳函数与声光偏转器的调制传递函数间的关系。适当选择声光介质与高斯光束(1/e~2振幅附近)的截断比可以增加分辨点数。     

Multiwavelength performance of an apodized acousto-optic switch

Use of the acousto-optic switch as a wavelength-routing element in WDM networks is described. The need for deep isolation between wavelength channels has resulted in the search for efficient sidelobe suppression techniques such as tapering of the acousto-optic profile by imbedding an optical waveguide in one arm of an acoustic directional coupler. The theory of sidelobe-suppression in the optical transmission function of a SAW-coupler apodized acousto-optic filter is presented. A low-sidelobe SAW-coupler-apodized AO switch was fabricated and used in a 1.5 micron multi-wavelength WDM switching demonstration employing four 4 nm-spaced optical channels. Crosstalk was below -19 dB for single wavelength selection and below -15 dB for arbitrary routing patterns, a dramatic improvement over unapodized AO switches     

Stabilisation of optical solitons by an acousto-optic modulator andfilter

Continuously shifting the optical frequency by acousto-optic modulators may substantially improve the stability of a periodically amplified soliton transmission system with filtering. This method, which is analogous to the sliding filter technique, may also be applied to fibre loop soliton generation and storage     

Optical beat-induced crosstalk of an acousto-optic tunable filterfor WDM network application

Acousto-optic tunable filters (AOTF) using TE-TM mode conversion are attractive for wavelength routers, such as WDM add/drop multiplexers or WDM cross-connect switching fabrics, due to their multichannel selectivity. However, their multichannel selection creates optical beat-induced crosstalk, the so called “coherent crosstalk”, due to the interaction of the lightwave with several acoustic waves. This paper evaluates the transmission characteristics of WDM systems employing AOTF's. First, we develop an analytical model of coherent crosstalk based on the coupled mode theory. Next, we examine coherent crosstalk induced BER degradation both theoretically and experimentally for optical WDM systems and show that the analytical studies well support the experimental results. Finally, maximum AOTF cascade number is estimated based on these results for WDM based wavelength routing networks     

Flattening of erbium-doped fibre amplifier gain spectrum using an acousto-optic tunable filter

An acousto-optic tunable filter is employed to flatten the gain spectrum of an erbium-doped fibre amplifier. A relatively flat gain spectrum of 15 nm in bandwidth with variations of less than 1 dB is obtained by simultaneously applying eight closely-spaced RF signals to the acousto-optic tunable filter.<>     

Tl3VS4 as an acousto-optic and surface wave material

Single crystals of thallium vanadium sulphide (Tl₃VS₄) up to 2 cm in length were grown from melts using the Stockbarger technique. This material has acoustic velocities as low as 8.73 × 10⁴ cm/sec for bulk shear waves and 8.7 × 10⁴ cm/sec for surface (Rayleigh) waves. In a sample oriented (001)Λ(110), k² was found to be 1.39%, and the temperature coefficient of delay −54 ppm for surface waves. The optical transmission is from 0.75 to 10.5 μm, and the indices of refraction range from 3.156 at 0.749 μm to 2.808 at 5.26 μm. These properties make it an attractive candidate for use in acousto-optic and acoustic surface-wave devices.     

声光调Q准连续YAG倍频光泵浦下的染料激光器研究

本文讨论了染料激光器在以KTP作倍频元件的YAG准连续倍频光泵浦下使用不同染料及不同选频元件时输出光束的线宽、转换效率及最佳运转参数。考虑到选频元件的选频损耗特性,通过对多波长速率方程组的数值解,讨论了在有限的泵浦光持续时间内,光束在染料激光腔内往返通过选频元件的次数对输出线宽的影响。计算结果与实验数据基本相符。     

多光束入射拓展声光偏转器带宽的研究

通过讨论声光偏转器的布拉格衍射带宽,分析其不同入射角度下的衍射效率分布,提出使用多束特定角度的平行光入射声光偏转器,从而拓展声光偏转器带宽.对磷化镓晶体进行的仿真计算表明,使用五束光入射时,带宽从40MHz增加到152MHz以上,带宽内衍射效率的标准差从0.1131减小到0.0387.     

Suppression of stimulated Brillouin scattering in a single-mode fibre by an acousto-optic modulator

Stimulated Brillouin scattering in a single-mode optical fibre was fully suppressed by launching two frequency beams passed through an acousto-optic modulator. A suppression ratio up to 30 dB was obtained for a frequency difference of 500 MHz between two beams. The experimental result agrees with the theoretical estimation. The method has great advantages for optical fibre systems using a continuous high-power laser source.