Parallel optical transmitter module using angled fibers and a V-grooved silicon optical bench for VCSEL array

We propose an advanced structure of optical subassembly (OSA) for packaging of the vertical-cavity surface-emitting laser (VCSEL) array, using (111) facet mirror of the V-groove ends formed in a silicon optical bench (SiOB) and angled fiber apertures. The feature of our OSA can provide a low optical crosstalk between neighboring channels, a low feedback reflection, and a large misalignment tolerance along the V-groove. We describe the optimized design of fiber angle, VCSEL position, and fiber position. The fabricated OSA structure consists of 12 channels of angled fiber array, 54.7/spl deg/ V-grooves, Au-coated mirrors on (111) end facet of the V-grooves, and flip-chip-bonded VCSEL array on a SiOB. In this structure, the beam emitted from the VCSEL is deflected at the 54.7/spl deg/ mirror of (111) end facet and propagated into the angled fiber. The angled fiber array was polished by 57/spl deg/. Fabricated OSAs showed a coupling efficiency of 30%-50% that is 25 times larger than that obtained from an OSA with a vertically flat fiber array. Our OSA showed large misalignment tolerance of about 90 /spl mu/m along the longitudinal direction in the V-groove. We fabricated a parallel optical transmitter module using the OSA and demonstrated 12 channels /spl times/2.5 Gb/s data transmission with a clear eye diagram.     

基于SFP的OLT新型光收发模块的设计

在分析光收发一体化模块特点的基础上,提出了基于SFP的EPON系统OLT收发模块的实现方案,针对硬件实现中各部分的功能和具体需求给出了核心模块的具体实现模块,满足GE-PON ITU-T G.984规定的输出平均光功率和消光比的要求。在设计过程中采用技术成熟的芯片来完成设计,该设计在尺寸、性能上满足ITU-T G.984的要求。     

波特率自适应的RS-485光电收发器模块设计

设计了一种基于硬件电路的RS-485光电收发器.对光电收发嚣模块的原理及使用场合进行简要论述.比较了工业控制领域中3种常用的光电收发器实现原理,对波特率自适应方法进行了详细介绍并给出原理说明.模块使用硬件电路搭建方向控制及整形电路,与软件控制相比更加实时.可靠,同时降低了通信系统的复杂性.经现场验证表明,相关性能指标完全满足要求.     

波特率自适应的RS-485光电收发器模块设计

设计了一种基于硬件电路的RS-485光电收发器。对光电收发器模块的原理及使用场合进行简要论述。比较了工业控制领域中3种常用的光电收发器实现原理,对波特率自适应方法进行了详细介绍并给出原理说明。模块使用硬件电路搭建方向控制及整形电路,与软件控制相比更加实时,可靠,同时降低了通信系统的复杂性。经现场验证表明,相关性能指标完全满足要求。     

单模光纤模场分布特性

介绍光纤的概念及其种类,光纤损耗和传输优点,并应用matlab软件数值模拟了单模光纤模场的分布特性,结论为光纤器件的制作提供参考.     

A compact coaxial-type optical transceiver module using ahalf-transmittance photodiode for TCM optical access networks

A compact coaxial-type optical transceiver module has been developed without using a conventional 3 dB optical coupler. This transceiver is composed of a newly designed half-transmittance photodiode (HT-PD) and a 1.3-μm-MQW-LD. An HT-PD is used both as a photodetector and as a window for LD light. Fiber output power of 1.15 mW at the drive current of 26 mA and responsivity of 0.48 A/W at the reverse-voltage of 5 V were obtained. Temperature dependence of responsivity is also reported     

Optical WDM transceiver module using wavelength-selective couplerand WDM-PD for optical access networks

A new optical wavelet division multiplexing (WDM)-transceiver module has been designed and fabricated for optical access networks. Conventional 1.3/1.55-μm WDM-coupler and Y-branch were replaced by a new wavelength-selective coupler in order to reduce module size. A new WDM-photodiode (PD), which was photosensitive to 1.3 μm light and transparent to 1.55 μm light, and a 1.55-μm PD were arranged in series along the optical axis. An MQW-FP-LD was used as a 1.3-μm transmitter. Fundamental characteristics were measured and discussed. Evaluation results, P_out of 0 dBm, responsivity of 0.36 A/W at 1.31 μm and 0.74 A/W at 1.55 μm, and IMD2 of -76.2 dBc, imply that this WDM-transceiver module design is promising to application for optical access networks     

A DIL-type miniature optical transceiver module using an InGaAsPhalf-transmittance photodiode for TCM optical access networks

A compact DIL-type miniature optical transceiver module has been developed without using a conventional 3 dB optical coupler. This transceiver is composed of a newly designed InGaAsP half-transmittance photodiode (HT-PD) and a 1.3-μm multiquantum-well laser diode (MQW-LD). An HT-PD is used both as a photodetector and as a window for laser diode (LD) light. Fiber output power of 0 dBm at the drive current of 33.8 mA and responsivity of 0.58 A/W at the reverse-voltage of 2 V were obtained. The fundamental characteristics of the HT-PD are studied and discussed     

High-speed photoreceivers using solder bumps and microstrip linesformed on a silicon optical bench

High-speed photoreceiver modules using silicon optical benches are described. These modules employ solder bumps for chip assembly and microstrip lines for electrical signal transmission. The assembly and wiring technologies are the same as those used in the planar lightwave circuit platforms we developed. A photoreceiver module consisting of a waveguide photodiode showed a very wide bandwidth greater than 20 GHz, and together with a spotsize-converted semiconductor optical amplifier, operated as an optical preamplifier that showed good receiver sensitivity of -20.3 dBm at 10 Gb/s nonreturn-to-zero     

Compact PLC-based optical transceiver module with automatic tunable filter for multi-rate applications

A full-duplex, simultaneous operation, multi-rate optical transceiver module for flexible optical access network systems has been fabricated. Based on a planar lightwave circuit (PLC) platform, the module is compact, highly sensitive, and supports multi-rate operation because it offers automatic transimpedance gain and band-pass filtering. This module will realise economical optical access network systems.     

Single mode grating coupling between thin-film and fiber optical waveguides

Optical directional coupling by means of a periodic perturbation is described between a clad, single mode, cylindrical fiber, and a thin-film planar waveguide. Codirectional coupling was achieved to a clad fiber, with 0.4 percent efficiency; allowing for the geometric mismatch, this is effectively 30 percent coupling. The fiber guided mode is accessed by reducing the fiber diameter by heating and pulling. Mode phase matching is achieved with a periodic grating sputter etched into the film. Unwanted grating induced interactions are minimized by restricting the guide parameters or by modifying the coupling mechanism. A perturbation analysis is used to calculate coupling coefficients and the design procedure for an optimum structure is explained. Measurements on grating couplers are described and the film/fiber codirectional coupling is shown to be effected by the grating.     

Measuring thermal and mechanical stresses on optical fiber in a DC module using fiber Bragg gratings

Fiber Bragg gratings (FBGs) can be used as sensors to monitor stress and test temperature during the processing and handling of optical fiber. As the FBG experiences a combination of mechanical and thermal loading, the return Bragg wavelength will shift proportionately to the magnitude of the load. This paper discusses the use of these sensors in quantifying induced stress on fiber during the packaging of a dispersion-compensating module (DCM) and the ensuing environmental exposure. There are two potential fiber-failure modes for fiber wound in DCMs, namely microbend-induced attenuation and fiber failure from fatigue. The ability to quantify fiber stress provides a useful feedback tool in the design phase of these modules that can aid in reducing the risk of mechanical and optical failure modes. A practical characterization process was developed to decouple thermal and stress effects on FBGs based on results from current literature and from this study. Uncoated Bragg sensors were found to respond linearly between -40 to 80/spl deg/C. Gratings with a protective polymer recoat departed from the linear behavior of the uncoated gratings below -5/spl deg/C. It was determined that the recoat material places less than 25 MPa (3.6 klbf/in/sup 2/) of axial compression on the fiber at -40/spl deg/C. Four gratings with different Bragg wavelengths were spliced into 10 km of fiber and wound into a DCM. The wind-induced stress on all four gratings quickly relaxed. The module was then thermal cycled between -40 and +75/spl deg/C. The overall stress on each grating was acceptably low for reliability purposes. The maximum stress of 17 MPa (2.5 klbf/in/sup 2/) was observed at the lowest temperature.     

一种多功能SFP光模块监测平台的设计与实现

设计并实现了-种SFP光模块实时监测平台,该平台可实时监测SFP光模块的温度、电压、激光器偏置电流以及发射和接收光功率等参量.该平台的应用简化了系统维护工作,提高了系统的可靠性.     

A new confocal combination lens method for a laser-diode module using a single-mode fiber

A new confocal combination lens method is proposed, which can overcome severe misalignment tolerances for an InGaAsP laser diode to single-mode fiber coupling. Lens 2 in the confocal two-lens method is divided into two lenses, that is, lenses 21 and 22. The optimal distance between lenses 1 and 21 is found to be shorter than that for a confocal condition. Lens 22 is attached to the input endface of the single-mode fiber, thus forming a virtual fiber. Using 0.06- and 0.18-pitch GRIN rod lenses as lenses 21 and 22, the lateral and axial misalignment tolerances for the virtual fiber are improved by three and nine times, respectively, in comparison with those for the single-mode fiber. High-coupling efficiency of -3.0 dB of the laser diode to the single-mode fiber can be easily obtained including Fresnel reflections.     

Analysis of a tunable single mode optical fiber coupler

We report the operation and the theoretical modeling of an efficient, tunable, and low-loss single mode fiber coupler. The coupler design follows a scheme previously reported, in which two optical fibers mounted in curved grooves in separate quartz substrates are polished until sufficient cladding material has been removed to permit optical coupling between the mated polished faces of the fibers. The results of a computer analysis of the distributed coupling taking place between the fibers are discussed, emphasizing the intuitive dependences of the coupling coefficient and effective interaction length of the device on its geometrical parameters. A detailed experimental analysis of fiber couplers follows in which we characterize two types of couplers made with different brands of single-mode fibers. Operation up to 100 percent coupling ratio and 50 dB extinction ratio between coupled and direct branch as well as operation in overcoupling regimes are demonstrated, both at visible and infrared signal wavelengths. Tuning curves are shown that emphasize the excellent tunability properties of such couplers in which the coupling ratio can be smoothly and continuously tuned between 0 and 100 percent. Experimental evidence of the relatively low loss level and very low polarization dependence of the fiber couplers are also presented. All experimental results, including an analysis of the influence of the refractive index of the intermediate layer of index-matching liquid between the polished faces of the fibers, are found to be very well predicted by our theoretical model.     

RS232型多串行通道单纤光端机的设计与实现

为有效延长数据的传输距离,解决电缆传输数据时电磁辐射、防电磁干扰、点对点设备间不共地、抗雷击以及信道资源共享等难题,采用多协议串行通信控制器Intel 82530和单纤双向TTL光收发一体模块设计了多串行通道单纤光端机。设计中,谋求了硬、软件规模最佳平衡点。对产生通信误差的原因进行分析,通过计算,选取合适的晶体振荡器,控制了多串行通道单纤光端机的通信误差,对常用的通信速率可获得准确的波特率。多串行通道单纤光端机可广泛应用于将串行数据远传至异地的单芯光纤的点到点连接,它克服了电缆传输数据的弊端,提高了数据的可靠性,同时也减少了有色金属和信道资源的消耗。     

非对称应力结构单模光纤偏振特性

本文通过理论分析,得出了非对称应力结构单模光纤,不管其应力结构如何,其本征传导模必定是线偏振的,在这种光纤中只存在线双折射,而没有任何形式的圆双折射。这一结果得到了实验证实。     

探索一种新型光纤连接器

介绍了一种新型的光纤连接器一锥形光纤连接器。利用局域模式耦合理论,分析了单根锥形光纤的传输特性和这种新型光纤连接器的耦合特性,并从实验上测定了由两根锥形光纤组成的锥形光纤连接器的耦合特性,从一定意义上证明了该光纤连接器的可行性,为优化光纤连接器的结构和性能,促进光纤通信事业的发展具有重要意义。     

Low-noise LD module with an optical isolator using a highly bi-substituted garnet film

We have developed a new type of laser diode (LD) module in the 1.3 ?m wavelength range coupled to a single-mode fibre with an optical isolator. The isolator comprises a highly Bi-substituted garnet film grown by liquid phase epitaxy (LPE) as a Faraday rotator. Since the garnet film is used also as a window of the hermetic seal of the LD, the reflection from the focusing lens used for fibre coupling is not allowed to return to the LD by the optical isolator. As a result, the reflection noise of the LD is prefectly suppressed. We have achieved a low-noise and compact LD module by using this construction.