两段级联宽带碲基掺铒光纤放大器特性研究

利用四能级结构速率方程组和光功率传输方程组,研究了在碲基掺铒光纤(EDTF)中内插一个光隔离器、形成两段级联的碲基掺铒光纤放大器(EDTFA)后对EDTFA性能的改善.结果表明,在给定泵浦方式、泵浦功率、纤芯掺杂浓度和输入信号功率条件下,两段级联EDTFA可以有效的抑制光纤中反向传输放大自发辐射(ASE)噪声,降低反转粒子数的消耗,从而提高信号增益、输出功率,并且降低了噪声系数.对不同光纤长度和光隔离器内插在光纤中不同位置的研究表明,当光纤为最佳长度和光隔离器在最佳位置处时,可使短波长信号增益增加10 dB,噪声系数减小1 dB,并进一步增加了放大带宽以及功率转换效率.     

Fiber-embedded in-line isolator

A fiber-embedded optical isolator with a low forward loss has been developed. The isolator consists of thermally diffused expanded core fibers, laminated polarizers, and a Faraday rotation garnet. Backward and forward losses at 1.3 μm wavelength are 44.0 and 0.9 dB, respectively. The isolator has a minute size, and its alignment is simple     

几种新型结构光纤隔离器

简要介绍了光纤隔离器的原理及其在光通信中的应用。着重分析讨论了几种新型光纤光隔离器的原理,结构及性 能。总结了光纤隔离器的发展现状,探讨了光纤隔离器的发展前景及方向。     

光纤传输用的磁光隔离器

本文报导了光纤通信用光隔离器的研究工作.隔离器由稀土铁石榴石法拉第旋转器及两只方解石棱镜组成.在波长为1.15微米时,器件插入损耗为2.4分贝,隔离比为34.8分贝.讨论了使用不同的复合稀土铁石榴石材料及采用不依赖偏振光技术对器件性能的改进.     

Design of a New Broad-Band Isolator

The design theory and experimental results of a proposed broad-band technique of an isolator are presented. The isolator not only has a broad-band backward loss but also a low broad-band insertion loss. The network constants and the performance are obtained in connection with the magnetic loss of ferrite, and they are confirmed by experimental data. The trial ultrawide-band isolator the performance of 20-dB isolation over the frequency band from 70 MHz to 800 MHz.     

On the Noise Parameters of Isolator and Receiver with Isolator at the Input (Short Paper)

Noise parameters of an isolator and those of a receiver with an isolator at the input are reviewed. Some comments on recently published results are offered.     

A phototransistor optical isolator noise model

A noise model for the phototransistor optical isolator is presented and used to predict optical isolator noise performance. Results are shown to agree with existing experimental data on phototransistor optical isolator noise. The model presented includes burst noise, flicker noise and shot noise.     

钒酸钇晶体楔型光隔离器

介绍了用钒酸钇晶体的与偏振无关的Ｗｅｄｇｅ型光隔离器的基本原理，用琼斯矢量法得到了插入损耗和隔离度的数学表达式，并介绍了隔离器的结构设计．制作的隔离器光纤到光纤的插入损耗为１．０４ｄＢ，隔离度为４２ｄＢ，回程损耗为４４．３ｄＢ，偏振灵敏度≤０．２ｄＢ，带宽大于４０ｎｍ，体积为１０×１０×４０ｍｍ３．     

两段型高性能光隔离器的设计与分析

提出了一种新的两段型高性能与偏振无关光隔离器的结构，给出了其设计思想和工作原理。对法拉第旋光器用的圆筒形磁铁进行了理论分析和计算，所得的结果对法拉第旋光器用的磁铁设计有具体的指导作用。通过借助矩阵光学理论，对光隔离器进行了数学分析，为与偏振无关光隔离器的性能分析和讨论作了有益的尝试。     

Design of a Full Waveguide Bandwidth High-Power Isolator

An analysis of the microwave fields in rectangular waveguide indicates that circular polarization of the H-vector components exists at two planes only and the location of these planes is frequency dependent. Also, an examination of Kittel's theory reveals that resonance in ferrites can be made to occur at different frequencies for a constant value of dc magnetic biasing field provided the ferrites are characterized by different values of saturation magnetization. These two effects have been used concurrently in the design of an X-band waveguide isolator for operation over a 45 per cent bandwidth, and at high power levels. The theory underlying the design of this isolator is presented. Included is a treatment of the parameters which affect the isolator design. Finally, an operative isolator is described and its experimental characteristics are reported.     

Amplifying Waveguide Optical Isolator With an Integrated Electromagnet

We have demonstrated an amplifying waveguide optical isolator with an integrated electromagnet. This provides a solution to the generally poor magnetic remanence of this type of isolator. The proof of principle is presented and optimization routes are discussed.     

Fibre-embedded optical isolator

A fibre-embedded optical isolator without a lens element is proposed and fabricated. The isolator consists of beam-expanding fibres, laminated polarisers and a Faraday rotation garnet. Backward and forward losses at 1.3 mu m wavelength are 36.9 and 1.6 dB, respectively.<>     

Lumped-element isolator with lower symmetrical configuration of three windings

Ideal isolator conditions are derived using circuit analysis in a lumped-element isolator with three windings at angles of /spl theta/ and /spl phi/. The angle /spl theta/ can be arbitrary; however, /spl phi/ is restricted to lie on the bisector of cross-angle /spl theta/ or the supplementary angle of /spl theta/. We found that the isolator with /spl theta/=/spl phi/=60 [deg] behaves the same as the one with conventional structure with /spl theta/=/spl phi/=120 [deg]. However, the former has a 0/spl deg/ phase shift and the latter a 180/spl deg/ phase shift between the input and output. The theoretical prediction was experimentally confirmed with an 800-MHz-band isolator.     

法拉第磁光隔离器

法拉第磁光隔离器可有效地消除光学反馈,在稳频激光、激光通讯和激光信息处理等系统中得到广泛应用。本文介绍了其工作原理、典型结构和各类法拉第材料的特性,说明了可调谐隔离器和宽带隔离器的结构和原理,并报告了国际市场上商品磁光隔离器的简况。     

液晶在光隔离技术中的应用研究

利用手性液晶的Bragg选择反射特性,理论分析了液晶在光隔离技术中的应用可能性.实验结果证实,液晶光隔离器对单色光具有较好的光隔离特性(光隔离度＝13dB)和较高的正向透过率(插入损耗＝1dB),在大口径光隔离器的制造上具有重要的应用价值.     

New configuration of polarisation-independent isolator using a polarisation-dependent one

In optical communication systems using fibre amplifiers, polarisation-independent isolators with high isolation are desirable. A simple effective method to realise polarisation-independent optical isolators is proposed. The isolator consists of spatial walk-off polarisers, half-wave plates, and a conventional polarisation-dependent isolator. The measured forward loss of the assembled isolator is 0.38 dB and 0.32 dB at 1.3 and 1.55 mu m wavelengths, respectively. The backward loss is 55.5 dB and 63.5 dB at 1.3 and 1.55 mu m wavelengths, respectively.<>     

偏振无关光隔离器的偏振相关损耗分析

在波动光学理论基础上,建立了求解光隔离器偏振相关损耗的理论模型,分析了影响光隔离器偏振相关损耗的因素.实际测量结果与理论分析相吻合.     

Optimum position of isolators within erbium-doped fibers

An isolator is used as an amplified spontaneous emission suppressing component within an erbium-doped fiber. The optimum isolator placement is both experimentally and theoretically determined and found to be slightly dependent upon pump power. Improvements of 4 dB in gain and 2 dB in noise figure are measured for the optimum isolator location at 25% of the fiber length when the fiber is pumped with 60 mW of pump power at 1.48 μm     

一种P波段高功率隔离器的研制

本文介绍了一种P波段隔离器的设计与实现方法,它具有低频段、大带宽、耐高功率等特点.首先,根据技术指标要求,对器件进行了结构方案设计;接着,综合分析了器件的耐功率、材料选型、工艺性等设计方法和设计思路;最后,研制出实物样机,并得到电性能实测结果,验证了设计的合理性.它的成功研制为此类微波器件的设计提供了经验与借鉴.     

100 W average power 10.6 µm isolator based on the interband Faraday effect in InSb

A 10.6 μm isolator based on the interband magnetic optical effect in InSb has been tested to throughput levels of 100 W average power. The interband isolator figure of merit (rotation/loss) has been shown to be nearly a factor of two greater than the optimum free carrier effect isolator. Employment of the isolator at a 10.6 μm laser radar field site has resulted in the improvement of frequency stability and Doppler resolution.