Integrated-optic device for a fibre laser Doppler velocimeter

We first demonstrate an integrated-optic device for a fibre laser Doppler velocimeter, which consists of a waveguide interferometer and a frequency shifter in z-propagation Ti-diffused LiNbO3. The device is also pigtailed with a single-mode fibre to pick up a Doppler-shifted signal. Using the fabricated device, the velocity of a moving object was successfully heterodyne-detected with a signal/noise ratio of 30dB.     

Antireflection coatings on lithium niobate waveguide devices using electron beam evaporated yttrium oxide

We report the first antireflection coatings for fibre pigtailed Ti:LiNbO3 waveguide devices optimised for the 1.55 ?m wavelength range. The coatings are single-layer, electron-beam-evaporated yttrium oxide films. A reflection of ?35 dB, sufficiently low for operation in conjunction with single-frequency lasers, has been demonstrated.     

Silicon based fibre pigtailed 1*16 power splitter

Experimental results for a fibre pigtailed 1*16 power splitter based on the radiative approach are reported, together with the results of temperature cycling over the range -40-70 degrees C. A novel technique using variable width waveguides has been used to improve the uniformity of 1*N splitters.<>     

Optical steering of dual band microwave phased array antenna using semiconductor laser switching

The first microwave phased array antenna steered by optical delay lines is presented. Delay times specified by the antenna steering angle were implemented by switching bias currents of high speed lasers pigtailed to the fibre optic delay lines. No beam squint was observed in the radiation pattern of the antenna as its frequency was switched from the L- to the X-band.<>     

20 Gbit/s, 1.55 μm strained-InGaAsP MQW modulator integrated DFBlaser module

The high-speed (20 Gbit/s) and highly efficient (2 V peak to peak for a 22 dB on/off ratio) operation of an MQW integrated electroabsorption modulator/DFB laser module is demonstrated. Output power from the module is over +3 dBm in the pigtailed singlemode fibre. To the authors' knowledge, this is the first report of 20 Gbit/s operation with a monolithically integrated light source     

Optical feedback-induced noise in pigtailed laser diode modules

The sensitivity of commercially available pigtailed laser diode modules to optical feedback, in terms of laser relative intensity noise, is investigated. A pigtailed laser diode model which is based on multimode rate equations, Langevin operators, and optical feedback terms in used to predict that operation in the coherence collapse region can be avoided in high-speed, short-haul, optical data links by trading off optical launch power into the pigtail with decreased laser/fiber coupling efficiency. Experimental results for three pigtailed laser diode modules indicate that with a laser/fiber coupling efficiency of 4%, an external feedback level of between -15 and -17 dB can be tolerated before the laser enters the coherence collapse region. Good correlation between these results and predictions from the numerical model is obtained.<>     

Development of Hard Plastic Clad Fiber (HPCF)-Compatible Devices and Demonstration of HPCF-PON

We report implementation and packaging of a whole line-up of hard plastic clad fiber (HPCF)-compatible devices: HPCF pigtailed 850-nm vertical-cavity surface-emitting lasers, HPCF pigtailed GaAs PIN photodiode, and 4times4 HPCF power splitter. Using these devices, an all-HPCF 4times4 passive optical network (PON) link suitable for short reach optical networks was successfully constructed. The PON link was operating well at a data rate of 1.25 Gb/s. The structures of the devices and their fabrication processes are discussed in detail along with characterizations of transmission performance by measuring the eye diagrams     

Integrated optics 4*4 switch matrix with digital optical switches

Reports on the first 4*4 switch matrix with digital optical switches as switch elements. The matrix is arranged in a tree structure, and comprises 24 switch elements and is pigtailed and packaged.<>     

Three-Optical-Port Module for Monolithic Optical Gate Integrated With Photodiode and Electroabsorption Modulator

Compact and stable three-optical-port modules are developed for optical gate devices monolithically integrated with photodiodes and electroabsorption modulators. The module has the same package size as ordinary laser-diode (LD) modules, and has three pigtailed fibers on two sides and the top. The module has high coupling efficiency and high stability for every optical port     

尾纤化非共焦FP谐振腔及其在光纤频分复用系统中的应用

报道了一种带输入单模光纤尾纤的器件化非共焦ＦＰ谐振腔，腔细度在１００以上，插入损耗低于５ｄＢ。该腔被应用于一个二路１４０Ｍｂ／Ｓ频分复用光纤传输系统中，借助于一精心设计的电子伺服系统，该腔在长期的系统实验中显示了十分优良可靠的性能。     

Self-aligned packing of an optical switch array with integratedtapers

An array of 2×2 switches with integrated tapers has been pigtailed using a silicon submount to self-align both chip and single-mode fibers. Electrical contacts were wirebonded through an opening etched in the submount. We report fiber-to-fiber insertion loss below 10 dB and measurements of wavelength and temperature dependence of the module     

Rugged, low-cost pigtailing approach for LiNbO3integrated optic devices

A new approach for attaching optical fibers to LiNbO₃ integrated optic devices is described. The all-solder approach, which uses no organic adhesives, is fast, robust, and low cost. A three-port fiberoptic gyro chip was pigtailed, and temperature cycled from 20 to 100°C with only +/-0.5-dB change in optical insertion loss     

Pigtailed tree-structured 8×8 LiNbO3 switch matrixwith 112 digital optical switches

We report on integrated optics Ti:LiNbO₃-based 8×8 switch matrices. The matrix design uses a tree structure with 112 digital optical switches as switch elements. The matrix, which has been pigtailed and packaged in an open package for convenient system demonstrator use, exhibits a worst case insertion loss of less than 15 dB     

Photovaractor for remote optical control of microwave circuits

A photovaractor for the remote optical control of microwave circuits was studied. The photovaractor was fabricated as a p-i-n photodiode placed in a pigtailed fiber optical module. The study of the impedance in the frequency range up to 3 GHz in darkness and under illumination has shown that the photovaractor capacitance strongly depends on the incident optical power. The capacitance variation of the photovaractor diode under illumination is discussed     

High-performance integrated erbium/sup +3/-ytterbium/sup +3/ codoped glass waveguide laser

We report the design and characterization of an efficient erbium/sup +3/-ytterbium/sup +3/ codoped ion exchanged glass distributed Bragg reflector (DBR) laser pumped by a 980-nm pigtailed laser source. Laser oscillation at 1536 nm is demonstrated with a pump threshold of 35 mW and a slope efficiency of 10.6%. The dependence of lasing performance on pump wavelength detuning is examined for different cavity designs.     

Folded-path self-pumped wavelength converter based on four-wave mixing in a semiconductor optical amplifier

A four-wave mixing wavelength converter with no external pump laser and very low input signal power requirements is characterized. The wavelength conversion occurs inside a high-reflection/antireflection coated semiconductor optical amplifier pigtailed with a fiber Bragg grating. The pump signal is provided by the lasing mode at the Bragg wavelength. A 1-mW optical signal modulated at 2.5 Gb/s is converted over 9 mm with error rates below 10/sup -9/.     

微小激光加工区温度测量的准确性研究

利用辐射测温系统对半导体微细加工高温区进行温度测量时,所测温度的准确性及分布细节会受多种因素的影响.理论分析表明,对于像差校正系统,杂散光及探测器光敏面面积是影响测温系统温度测量准确性的主要因素,因此将原有探测器更改为带单模尾纤式探测器以限制杂散光并减小光接收面面积.实验证明这种方法是有效的,基本满足微小面元温度测量的要求.     

大型机械零部件孔同轴度测量技术研究

本文提出测量大型机械零部件孔同轴度的新方法。采用单模光纤尾纤半导体激光器作光源的激光准直系统为测量提供的基准线。同轴度由多个截面的光斑中心坐标值和圆周采样数据按一定的算法计算。测量结果表明,该方法具有良好的可行性和灵活性。该系统可用于大孔同轴度的高精度测量。     

Absorption Dynamics in All-Optical Switch Based on Intersubband Transition in InGaAs–AlAs–AlAsSb Coupled Quantum Wells

We developed a pigtailed fiber module including an intersubband transition all-optical switch using InGaAs-AlAs-AlAsSb coupled double quantum wells and studied the absorption saturation dynamics. An increased extinction ratio was obtained by optimizing the delay time between control and signal pulses due to the reduced effect of two-photon absorption. An extinction ratio of 10 dB was obtained for a fiber input pulse energy of 16 pJ (200-fs pulsewidth). The absorption recovery time varied from 600 fs to 2 ps depending on the control pulse energy     

A unidirectional Er3+-doped fiber ring laser withoutisolator

An Er³⁺-doped fiber ring laser with unidirectional operation without optical isolator has been investigated for different cavity conditions. The fiber ring laser cavity is built in such a way that the optical fields propagating in the two directions suffer different losses. As a consequence, the laser oscillation appears in a quasi-unidirectional form. By incorporating a fiber pigtailed bandpass filter to enhance mode competition, a purely unidirectional tunable fiber ring laser is obtained with high efficiency and broad tunability