微型单级偏振无关光隔离器的设计与实验

研制了一种新型的微型单级偏振无关光隔离器,给出了光隔离器中自聚焦透镜、双折射晶体平行平板和法拉第旋转片的设计,介绍了光隔离器的制作方法,并对其性能进行了测试。实验结果表明:插入损耗为0.5 dB,0λ±20 nm带宽范围内最小隔离度为30 dB,最大隔离度为45 dB,偏振相关损耗小于0.1 dB,偏振模色散小于0.05 ps。     

在线式双级光隔离器的隔离度分析

采用等效琼斯矩阵方法,分析了制约在线式双级光隔离器隔离度的各种因素,提出了对两级采用不同角度的楔角片来制作双级隔离器的方案,并实现批量生产。根据理论分析,隔离度可以达到58dB以上;量产结果表明,80％的产品隔离度达到58dB以上,而平均隔离度为61dB。     

大口径磁光隔离器隔离度单次测量技术

搭建了全光纤化的大口径磁光隔离器隔离度单次测量系统,体积小且调节灵活方便,在大口径隔离器的在线测量方面具有独特优势。利用光纤器件在光束传输和耦合方面的优势以及磁光隔离器的工作特点,采用透过率相对测量法和静动态对比法实现了隔离度的单次测量。实验可测量动态范围达到33dB以上,且通过调整光纤耦合器分光比可使测量动态范围进一步提高到50dB以上。该方法有效消除了输入信号脉冲功率及偏振态抖动等因素对测量精度的影响,在输入信号脉冲能量和偏振态随机抖动的情况下,仍然可实现抖动波峰波谷(PV)值为2.2%的测量精度。     

与偏振无关光隔离器性能参数的测量

光隔离器的性能是由内部各个组件的性能和装配所决定。对两端带有连接器的偏振无关光隔离器，给出了利用光功率计和光谱分析仪测量隔离度、插入损耗、带宽、连接损耗和回波损耗等性能参数的方法。     

光通信系统用光隔离器研究

详细介绍了在线式偏振无关光隔离器和微型化偏振相关光隔离器的工作原理，以及两种隔离器系列的各项性能指标。其主要性能指标达到国内先进水平，并达到了９０年代国外同类光隔离器的水平。     

Walk－off型光隔离器的隔离度和插入损耗分析

本文介绍了与偏振无关的ｗａｌｋ－ｏｆｆ型光隔离器的原理和结构，从理论和实验两方面分析了影响隔离度和插入损耗的因素，定量计算了加工、调整误差、消光比等对隔离度和插损的限制，给光隔离器的选材、加工和调整提供了依据。     

长波长铟置换铋钙钒石榴石单晶光隔离器

本文采用铟置换铋钙钒石榴石单晶研制了新型非稀土元素石榴石单晶光隔离器。有1.3μm和1.5μm波段两种器件;在1.3μm波长时,隔离度≥40 dB,插入损耗1.0 dB;在1.523μm波长时,隔离度>43 dB,插入损耗1.1 dB,其中插入损耗中包括两个偏振棱镜的Fresnel反射损耗约0.8 dB。     

外界磁场对偏振无关隔离器的影响及其利用

就外界磁场对偏振无关隔离器隔离度的影响作了实验研究，观察到一定强度的外界磁场可引起偏振无关隔离器最大隔离度对应的波长发生偏移。在目前实验条件下，测得32mT的磁场可引起18．36nm波长的变化，对应的最大隔离度指标劣化14ddB。因此在使用隔离器时应尽量避免外界磁场对其性能的影响。另一方面，利用这一现象，也可以通过外界磁场来改变或移动隔离器的最佳工作波长，提高其在特定波长处的隔离度，为隔离器的应用增强了灵活性。     

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．     

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.     

Polarization independent isolator using spatial walkoff polarizers

A novel type of polarization-independent optical isolator is described which utilizes the polarization walkoff provided by birefringent crystals. Isolation of 44 dB is measured at a wavelength of 1.3 mu m with single-mode fiber insertion loss of 1.5 dB. A temperature-independent scheme is also described that provides at least 39 dB of isolation over the temperature range of 25-75 degrees C.<>     

新颖的掺铒光纤放大器无源复合组件的研究

报道了一种将光波分复用器与光隔离器集于一体的适用于掺铒光纤放大器的新颖复合组件。根据复合组件的性能指标对组件的结构参数进行了优化设计。实际制作的复合组件，得到泵浦光插入损耗＜０．６ｄＢ，信号光的插入损耗＜１．５ｄＢ，反向隔离度＞４２ｄＢ，体积为９×４５ｍｍ３。将复合组件用于掺铒光纤放大器中（前向泵浦方式）得到约３０ｄＢ的小信号增益，１０ｄＢｍ的饱和输出功率。     

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.<>     

Bulk optical isolator tunable from 1.2 ?m to 1.7 ?m

A uniquely designed, mechanically tunable, bulk optical isolator for the 1.2 to 1.7 ?m wavelength range is described. The isolator can be tuned for isolation better than 32 dB over the operating wavelength range with a forward loss ranging from -3.6 dB at 1.2 ?m to -0.8 dB at 1.6 ?m.     

Polarization insensitive optical amplifier consisting of twosemiconductor laser amplifiers and a polarization insensitive isolatorin series

A polarization-insensitive optical amplifier consisting of two semiconductor laser amplifiers and a polarization-insensitive isolator in series is presented. The isolator not only eliminates the cavity coupling between two amplifiers, but also rotates polarized forward light by 90°. Experiments demonstrate the elimination of cavity coupling and a polarization sensitivity of 0.6 dB with a gain of 26 dB     

Optoelectronic isolator for microwave applications

The analysis, design, and implementation of a hybrid optoelectronic isolator for microwave applications is described. The device is designed to operate over a 300-MHz bandwidth centered at 3 GHz. The prototype achieves isolation greater than 80 dB and a forward power gain of 0.13 dB at its center frequency. Prototype results indicate that use of this device in an operating system can control self-oscillation in high-gain receivers and/or provide useful isolation of sensitive radars. Furthermore, the required size is smaller, especially with monolithic implementation, while providing isolation far in excess of competing technologies. For comparison, a packaged ferrite isolator would be about twice the size of the prototype while providing only 30 dB of isolation     

Radiative optical isolator and circulator

A novel radiative optical isolator and a circulator are discussed in this paper. It is numerically estimated that with λ=1.3 μm, 45-dB isolation ran be achieved with an isolator of 8 mm in length. For a 21.5-mm-long 4-port circulator, the achievable isolation is about 45 dB, with approximately 1-dB insertion loss