激光测距APD偏压电路的最佳设计外文翻译
低纹波低功耗自动控制APD偏压电路
低纹波低功耗自动控制APD 偏压电路张志强1,王 萍1,邹 宇1,王艳永2(1.天津大学电气与自动化工程学院,天津300072;2.北京博飞仪器股份有限公司,北京101149)摘 要:全站仪红外测距系统接收电路采用APD 雪崩光电二极管作为接收器件,它的精度对后级的信号处理及测量精度起着决定性的影响,针对其高精度要求,提出两种APD 偏压电路。
前者采用交流反馈网络消除冲击电压,提高了开关管寿命,采用三级滤波网络极大的降低了电路纹波从而提高了测量精度;后者采用专用芯片控制电路电源,使储能电感处于非连续工作状态,大大降低了电路的功耗,同时采用4个变容二极管既升高了电压,又减小了纹波。
两种电路均具有可自动控制,且能对APD 的内部增益进行全范围补偿的优点。
实践证明,电路工作性能理想,提高了测距精度。
关键词:红外测距;APD ;偏置电压;温度补偿中图分类号:TN36412;P204 文献标识码:B 文章编号:1006-7949(2007)01-0062-04APD bias voltage circuit of low ripple and low pow er autom atic controllZHAN G Zhi 2qiang 1,WAN G Ping 1,ZOU Yu 1,WAN G Yan 2yong2(1.School of Electrical Engineering and Automation ,Tianjin University ,Tianjin 300072,China ;2.Beijing BoFei Instrument Co.,Ltd.,Beijing 101149,China )Abstract :The APD is used in the receive circuit of total station infrared distance measure system.Its accuracy have crucial influence on signal process and measure accuracy.In consideration of its high accuracy requirement ,this paper presents two APD bias voltage circuits.the former adopts intercourse feedback network to slake the impact voltage ,and the MOSFET ’s longevity is prolonged.It also adopts third class filter to depress the voltage ripple.The latter circuit introduces a special chip to control the power ,the inductance works in discrete mode ,it reduces power consumption ,and the four variodes is used to impove the voltage and depress the ripple.These two circuits have the advantages of automatic control and the inner gain of APD can also be compensated for all range.The circuits are proved to perform well in practice and the measure accuracy is improved.K ey w ords :infrared distance measure ;APD ;bias voltage ;temperature compensation收稿日期:2006-10-09作者简介:张志强(1979~),男,硕士研究生. 雪崩光电二极管APD (Avalanche Photodiode )是一种新型高灵敏光电探测与传感器件。
光电二极管偏置电路设计
光电二极管偏置电路设计英文回答:Photodiode Bias Circuit Design.Introduction.A photodiode is a semiconductor device that converts light into electrical current. It is a type of photodetector that is used in various applications, such as optical communication, position sensing, and light measurement. The performance of a photodiode is greatly influenced by its bias circuit.Bias Circuit.The bias circuit of a photodiode is a circuit that provides the necessary voltage and current conditions for the operation of the photodiode. The main purpose of the bias circuit is to establish a reverse bias across thephotodiode, which allows the photodiode to generate a photocurrent when illuminated.There are two main types of bias circuits:Constant Voltage Bias Circuit: This circuit maintains a constant voltage across the photodiode, regardless of the light intensity. It is typically used in applications where a stable photocurrent is required.Constant Current Bias Circuit: This circuit maintains a constant current through the photodiode, regardless of the light intensity. It is typically used in applications where a wide dynamic range is required.Design Considerations.The design of a bias circuit for a photodiode involves several important considerations:Reverse Bias Voltage: The reverse bias voltage applied to the photodiode should be large enough to ensure that thephotodiode is fully depleted and operates in the reverse-biased region.Load Resistance: The load resistance connected to the photodiode determines the output current and voltage of the photodiode. A higher load resistance will result in ahigher output voltage and a lower output current.Dark Current: The dark current is a small current that flows through the photodiode even when it is not illuminated. The bias circuit should be designed tominimize the dark current.Responsivity: The responsivity of a photodiode is the ratio of the output current to the incident light intensity. The bias circuit should be designed to maximize the responsivity of the photodiode.Design Procedure.The design procedure for a bias circuit for aphotodiode typically involves the following steps:1. Determine the desired operating voltage and current for the photodiode.2. Select the type of bias circuit (constant voltage or constant current).3. Calculate the required reverse bias voltage and load resistance.4. Choose appropriate components for the bias circuit.5. Test and verify the performance of the bias circuit.Conclusion.The bias circuit is an essential part of a photodiode system. By carefully designing the bias circuit, it is possible to optimize the performance of the photodiode and meet the specific requirements of the application.中文回答:光电二极管偏置电路设计。
一种在光模块生产中快速调试apd偏压的方法
一种在光模块生产中快速调试apd偏压的方法一、背景在光模块生产过程中,调试apd偏压是一项重要的工艺步骤。
apd(Active Pump Diode)是一种主动泵浦激光器,用于驱动光模块中的激光器工作。
调试apd 偏压的目的是确保激光器工作在最佳状态,从而提高光模块的性能和稳定性。
然而,传统的调试方法往往需要较长时间,且容易出错,影响生产效率。
因此,我们提出了一种在光模块生产中快速调试apd偏压的方法。
二、方法1. 准备工作:在调试apd偏压之前,需要对光模块进行初步的外观检查和性能测试,确保其符合生产标准。
2. 确定初始偏压值:根据光模块的性能参数和生产经验,初步确定apd的初始偏压值。
3. 调试过程:a. 将光模块放入测试设备中,启动测试程序;b. 观察测试结果,根据激光器的性能指标调整apd偏压;c. 重复步骤b,直到激光器工作在最佳状态,且性能指标满足要求。
4. 优化偏压:在调试过程中,可以通过改变apd的工作模式、调整驱动信号等手段,进一步优化偏压效果。
5. 记录数据:将调试过程中的各项数据(如apd偏压、激光器性能指标等)记录下来,为后续生产提供参考。
三、优势1. 快速调试:通过上述方法,可以在较短的时间内完成apd偏压的调试,提高生产效率。
2. 准确度高:通过逐步调整和优化偏压,可以确保激光器工作在最佳状态,提高光模块的性能和稳定性。
3. 可重复性好:通过记录数据,可以为后续生产提供参考,确保生产过程的可重复性。
四、结论综上所述,本方法通过快速、准确、可重复地调试apd偏压,提高了光模块生产的效率和质量。
我们相信,该方法将在光模块生产领域得到广泛应用,并为行业发展做出积极贡献。
五、建议和展望1. 建议在实际生产过程中,加强对测试数据的分析和管理,以便更好地指导生产和优化产品性能。
2. 展望未来,我们可以进一步研究apd偏压的自动调整和优化算法,以提高调试过程的自动化程度和精度,进一步推动光模块生产的发展。
基于APD的远程激光测距系统光电匹配研究
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低耗低纹波可控式APD偏置电路
3 结论与说明
(1) 在图 1 所示参数情况下 ,当 V R取 0~4. 5 V 时 ,输出电压 V OU T的变化范围约为 90~160 V , 图 2 电路的输出调节情况与图 1 相当 。
(2) 电路总功耗 ,在电路元件与参数选配合理 的情况下 ,图 1 电路在 10 mW 以下 ,而图 2 电路要 在 80 mW 以上 。电路输出电压波纹 ,在空载情况 下 ,图 1 电路达数百毫伏 ,而图 2 电路在 50 mV 以 下 ;在 1~2 mA 负载电流情况下 ,图 1 电路要达近 伏特量级 ,而图 2 电路在 100 mV 以下 。不过需要 说明的是 :高压发生电路输出电压的纹波 ,对 APD 的信号检测信噪比的影响 ,在单频或窄带信号检测 情况下 (大多数应用场合都是如此) 影响都比较小 , 因为电路都有窄带滤波器 ,可以较好地滤去 APD 偏 压纹波噪声 。
《半导体光电》2002 年第 23 卷第 1 期 曾毓敏 : 低耗低纹波可控式 APD 偏置电路
实用电路
低耗低纹波可控式 APD 偏置电路
曾毓敏
( 南京师范大学 物理科学与技术学院 ,江苏 南京 210097)
摘 要 : 给出了两种非常适合作为 APD 偏置电路的高效 、低耗 、低纹波输出 、可控式高压发 生电路 ,同时给出了电路的应用说明 。
图 1 低功耗 APD 偏压电路
本电路中 IC1 为一电压比较器 ,用于比较基准 电压 V R与电路输出电压 V OU T ;四与非门 IC2 构成 一个振荡器 、一个置位/ 复位锁存器和一个缓冲反相 器 ;MOS 管 B G 与电感 L 构成高压脉冲转换器 ,它 驱动由 D1/ C1 、D2/ C2 、D3/ C3 组成的二极管/ 电容 充电泵 ,产生输出电压 V OU T 。IC1 把 V OU T与 V R进 行比较 ,若 V OU T超过设定值 , IC1 输出高电平 ,控制 锁存器锁存为高电平 ,振荡器停止工作 ,缓冲器输出 低电平 , 使高压脉冲转换器停止工作 , 输出电压 V OU T相应下降 。而当 V OU T低于设定值时 , IC1 输
基于APD激光窄脉冲探测系统的研究
基于APD激光窄脉冲探测系统的研究崔一惟;贺伟【摘要】The laser narrow pulse detection system is mainly composed of transmitting and receiving parts. Since low⁃power laser narrow pulse signal is weak,it is urgent to improve the optical gain and the detection efficiency. The traditional method is to select a sensitive photoelectric detection device to solve the problem by amplifying circuit. The avalanche diode with internal gain is adopted in this paper as a photosensitive element. On the basis of this,the optical system is added to conduct amplifica⁃tion processing before detection,which can improve the efficiency of detection effectively.%激光窄脉冲探测系统主要是由发射和接收两部分组成,小功率的激光窄脉冲信号比较微弱,所以提高光增益增加探测效率是亟待解决的。
传统的解决手段是选择灵敏的光电探测器件,后续经过放大电路进行解决。
这里采用具有内部增益的雪崩二极管作为光敏元件,在此基础上增加光学系统,使探测前就进行放大处理,进而有效地提高探测效率。
【期刊名称】《现代电子技术》【年(卷),期】2015(000)004【总页数】4页(P135-138)【关键词】激光探测;APD;温控系统;光学系统【作者】崔一惟;贺伟【作者单位】西安邮电大学,陕西西安 710061;西安邮电大学,陕西西安710061【正文语种】中文【中图分类】TN312+.7-340 引言随着1960年第一个红宝石激光器的诞生,相应的激光探测技术也越来越受人们的关注与研究,激光测距、激光雷达、激光制导等国防级应用都离不开窄脉冲激光探测技术[1]。
面向LiDAR应用的APD单片前端读出电路设计
第48卷第S1期红外与激光工程2019年4月Vol.48No.S1Infrared and Laser Engineering Apr.2019面向LiDAR应用的APD单片前端读出电路设计丁春楠1,叶茂1,夏显召1,谢绍禹1,2,李尧1,赵毅强1(1.天津大学微电子学院成像与感知微电子技术重点实验室,天津300072;2.天津津航技术物理研究所,天津300308)摘要:针对基于雪崩光电二极管(avalanche photodiode,APD)的激光雷达(light laser detection and ranging,LiDAR)应用需求,设计并实现了一款具有高集成度的模拟前端读出电路芯片。
该芯片集成了高增益宽带跨阻放大器(transimpedance amplifier,TIA)、固定增益电压放大器、高速实时比较器以及低压差分信号(low voltage differential signaling,LVDS)接口电路等。
高增益宽带跨阻放大器采用电阻反馈式结构,电压信号以伪差分信号的形式输出,抗干扰能力较强。
固定增益电压放大器采用电阻反馈同相放大器结构。
比较器利用未经补偿的开环放大器实现。
读出电路采用LVDS输出,实现了与后端FPGA的互连,进一步提高了系统集成度。
该芯片采用chrt0.18μm工艺设计,面积约为0.9mm×1.9mm。
在3.3V供电电压下,测试结果显示跨阻增益为83.6dBΩ,带宽为120MHz,整体链路能对脉宽为5ns 的脉冲作出有效响应,LVDS输出电压符合FPGA接口要求。
关键词:激光雷达;APD;跨阻放大器;伪差分;LVDS中图分类号:TN492文献标志码:A DOI:10.3788/IRLA201948.S106004Monolithic front-end readout circuit for LiDARusing APD detectorDing Chunnan1,Ye Mao1,Xia Xianzhao1,Xie Shaoyu1,2,Li Yao1,Zhao Yiqiang1(1.Key Laboratory of Imaging and Sensing Microelectronic Technology,School of Microelectronics,Tianjin University,Tianjin300072,China;2.Tianjin Jinhang Institute of Technical Physics,Tianjin300308,China)Abstract:A high integration density front-end readout circuit(ROIC)was presented and designed in allusion to the kind of light laser detection and ranging(LiDAR)using avalanche photodiode(APD) detector.The front-end readout circuit consisted of high-gain broadband transimpedance amplifier(TIA), fixed gain voltage amplifier,high-speed real-time comparator,low voltage differential signaling(LVDS) output interface et al.TIA adopted resistance feedback structure.The output voltage signal of TIA connected to next stage through the way of pseudo-difference signaling,therefore obtaining better anti-interference ability.Fixed gain voltage amplifier was a non-inverting amplifier with resistance feedback network.Then a decompensated open-loop amplifier was used for the comparator in the chip.The ROIC can connect with FPGA directly profiting from the LVDS,again improving the integration density of the收稿日期:2018-11-11;修订日期:2018-12-14基金项目:国家自然科学基金(61604109);广西创新驱动发展专项(2018AA13005)作者简介:丁春楠(1996-),男,硕士生,主要从事激光雷达方面的研究。
APD偏压的自适应电路设计
电子技术• Electronic TechnologyAPD 偏压的自适应电路设计文/朱斌本文介绍了雪崩光电二极管摘 偏压、增益、温度三者之间的关系。
要 设计出基于PIC 单片机的自适应 ■调节电路,介绍了电路的具体设计方案、硬软件实施方法,并在 理论分析的基础上进行了验证及 改进。
实验表明,该电路电压偏 差小于0. 5V,可满足工程化应用。
图1:电路设计方案原理框图【关键词】APD 偏压自适应电路设计1引言雪崩光电二极管(avalanche photodiode ,APD)具有体积小、灵敏度高、响应速度快等 特点,特别是在内部雪崩倍增时可将信号倍增 上百倍,且倍增后的噪声仅与运放本底噪声水平相当,从而极大地提髙了系统的信噪比,被 广泛应用于光纤通信、激光测距、星球定向和军事测控等领域。
APD 工作时的信噪比(SNR)为:2q(I p + I DA )BM !F + 2qI DS (J)式(1)中:M 为APD 的雪崩增益,I ”为M=1时的光电流,和输入光信号功率成正 比,I da 为参与倍增的暗电流,I ds 为不参与倍 增的暗电流,B 为带宽,F 为过剩噪声系数,K 为波尔兹曼常数,T 为绝对温度,陽为负载, q 为输入光信号功率。
通过式(1)可以看出, 在APDI 作时随着雪崩增益M 的增大,信噪 比也逐渐增加;M 继续增大信噪比反而会变 小,故存在一个最优雪崩倍增因子Mp :M | 2KT |小式(2)中,x 为APD 的过剩噪音指数,其大小取决于APD 的结构和制作材料的不同。
从式(2)中可知,APD 的最佳雪崩增益与温度、 输入信号光功率、器件自身的暗电流及负载大 小等有关。
其中温度的影响最为突出,温度的变化是影响最佳雪崩增益的关键因素。
因使用环境的不同,APD 不总是工作在一个恒温的 状态。
当温度变化时,最优雪崩倍增因子也随 之发生改变。
根据作者在理论和实验的研究中 发现,当APD 增益比较恒定时,其偏压Vb 与 温度T 之间存在一定的线性关系,该线性关系为:V b = ^L(0.51T-lI.98)+V BK ⑶式(3)中,Pp 是入注光功率,I ]是APD 的量子效率,V br 是PN 结的反向击穿电压。
光电系毕业论文外文翻译半导体激光器适用于毕业论文外文翻译+
毕业设计(论文)英文翻译姓名学号0811122121所在学院理学院专业班级2008级光信1班指导教师日期2012年4月20日英文原文1.5 Experimental Setup Due to the many concepts and variations involved in performing the experimentsin this project and also because of their introductory nature Project 1 will very likelybe the most time consuming project in this kit. This project may require as much as 9hours to complete. We recommend that you perform the experiments in two or morelaboratory sessions. For example power and astigmatic distance characteristics maybe examined in the first session and the last two experiments frequency andamplitude characteristics may be performed in the second session. A Note of Caution All of the above comments refer to single-mode operation of the laser which is avery fragile device with respect to reflections and operating point. One must ensurethat before performing measurements the laser is indeed operating single-mode.This can be realized if a single broad fringe pattern is obtained or equivalently a goodsinusoidal output is obtained from the Michelson interferometer as the path imbalanceis scanned. If this is not the case the laser is probably operating multimode and itscurrent should be adjusted. If single-mode operation cannot be achieved by adjustingthe current then reflections may be driving the laser multimode in which case thesetup should be adjusted to minimize reflections. If still not operating single-modethe laser diode may have been damaged and may need to be replaced. Warning The lasers provided in this project kit emit invisible radiation that can damagethe human eye. It is essential that you avoid direct eye exposure to the laser beam.We recommend the use of protective eyewear designed for use at the laser wavelengthof 780 nm. Read the Safety sections in the Laser Diode Driver Operating Manual and in thelaser diode section of Component Handling and Assembly Appendix A beforeproceeding.1.5.1 Semiconductor Diode Laser Power Characteristics1. Assemble the laser mount assembly LMA-I and connect the laser to its powersupply. We will first collimate the light beam. Connect the laser beam to a videomonitor and image the laser beam on a white sheet of paper held about two to tencentimeters from the laser assembly. Slowly increase the drive current to the laser andobserve the spot on the white card. The threshold drive current rating of the laser issupplied with each laser. Increase the current to about 10-20 mA over the thresholdvalue. With the infrared imager or infrared sensor card observe the spot on the card andadjust the collimator lens position in the laser assembly LMA-I to obtain a bright spoton the card. Move the card to about 30 to 60 centimeters from the lens and adjust thelens position relative to the laser to obtain a spot where size does not vary stronglywith the position of the white card. When the spot size remains roughly constant asthe card is moved closer or further from the laser the output can be consideredcollimated. Alternatively the laser beam may be collimated by focusing it at adistance as far away as possible. Protect fellow co-workers from accidental exposureto the laser beam.2. Place an 818-SL detector on a post mount assembly M818 and adjust its positionso that its active area is in the center of the beam. There should be adequate opticalpower falling on the detector to get a strong signal. Connect the photodetector to thepower meter 815. Reduce the background lighting room lights so that the signalbeing detected is only from the laser. Reduce the drive current to a few milliamperesbelow threshold and again check to see that room light is not the dominantsignal atthe detector by blocking the laser light.3. Increase the current and record the output of the detector as a function of laser drivecurrent. You should obtain a curve similar to Figure 1.2. If desired the diodetemperature may also be varied to observe the effects of temperature on thresholdcurrent. When examining laser diode temperature characteristics the laser diodedriver should be operated in the constant current mode as a safeguard againstexcessive currents that damage the diode laser. Note that as the diode temperature isreduced the threshold decreases. Start all measurements with the diode current off toprevent damage to the laser by preventing drive currents too high above threshold.To prevent destruction of the laser do not exceed the stated maximum drive current ofthe laser.1.5.2 Astigmatic Distance Characteristics The laser diode astigmatic distance is determined as follows. A lens is used tofocus the laser beam at a convenient distance. A razor blade is then incrementallymoved across the beam to obtain data for total optical power passing the razor edge vs.the razor blade position. A plot of this data produces an integrated power profile of thelaser beam Figure 1.9a which through differentiation exposes the actual powerprofile Figure 1.9b which in turn permits determination of the beam diameter W.A beam diameter profile is obtained by measuring the beam diameter while varyingthe laser position. Figure 1.9c illustrates the two beam diameter profiles of interest:one for razor edge travel in the direction perpendicular to the laser diode junctionplane and the other for travel in the direction parallel to the junction plane. Theastigmatic distance for a laser diode is the displacement between the minima of thesetwo profiles. This method is known as the knife edge technique.1. Assemble the components shown in Figure 1.8 with the collimator lens LC in therotational stage assembly RSA-I placed roughly 1 centimeter away from the laser.The beam should travel along the optic axis of the lens. This is the same lens used incollimating the laser in the previous setup. The approximate placement of all thecomponents are shown in the figure. Make sure that the plane of the diode junctionxz plane in Figure 1.1 is parallel with the table surface.2. Due to the asymmetric divergence of the light the cross-section of the beamleaving the laser and further past the spherical lens is elliptical. The beam thus hastwo distinct focal points one in the plane parallel and the other in the planeperpendicular to the laser diode junction. There is a point between the two focalpoints where the beam cross-section is circular. With the infrared imager and a whitecard roughly determine the position where the beam cross-section is circular. Figure 1.9 – Procedure for finding astigmatic distance.3. Adjust the laser diode to lens distance such that the razor blades are located in thexy plane where the beam cross-section is circular.4. Move the laser diode away from the lens until minimum beam waist is reached atthe plane of razor blades. Now move the laser diode about 200 m further away fromthe lens.5. Move razor blade 1 in the x direction across the beam through the beam spreadθxand record the x position and detected intensity at each increment ≤100 mincrements. The expected output is shown in Figure 1.9. The derivative of this curveyields the intensity profile of the beam in the x direction from which the beamdiameter is determined.6. Repeat with razor blade 2 for θy in the y direction.7. Move the laser closer to the lens in increments ≤50 m through a total of at leastthan 500m. Repeat Steps 5 and 6 at each z increment recording the z position.8. Using the collected data determine the beam intensity profiles in the x and ydirections as a function of the lens position z. This is done by differentiating each dataset with respect to position. Then calculate the beam diameter and plot as a functionof z. The difference in z for the minimum in θx and θy isthe astigmatic distance of thelaser diode. Use of computer software especially in differentiating the data is highlyrecommended. If the laser junction is not parallel to the table surface then for eachmeasurement above you will obtain an admixture of the two beam divergences andthe measurement will become imprecise. If the laser is oriented at 45° to the surfaceof the table the astigmatic distance will be zero. Different laser structures will have different angular beam divergences and thusdifferent astigmatic distances. If you have access to several different laser types gainguided index guided it may be instructive to characterize their astigmatic distances.1.5.3 Frequency Characteristics of Diode Lasers In order to study frequency characteristics of a diode laser we will employ aMichelson interferometer to convert frequency variations into intensity variations. Anexperimental setup for examining frequency and also amplitude characteristics of alaser source is illustrated in Figure 1.10.1. In this experiment it is very possible that light may be coupled back into the laserthereby destabilizing it. An optical isolator therefore will be required to minimizefeedback into the laser. A simple isolator will be constructed using a polarizing beamsplitter cube and a quarterwave plate. We orient the quarterwave plate such that thelinearly polarized light from the polarizer is incident at 45° to the principal axes of thequarterwave plate so that light emerging from the quarterwave plate is circularlypolarized. Reflections change left-circular polarized light into right-circular or viceversa so that reflected light returning through the quarterwave plate will be linearlypolarized and 90° rotated with respect to the polarizer transmission axis. The polarizerthen greatly attenuates the return beam. In assembling the isolator make sure that the laser junction xz plane in Figure1.1 is parallel to the surface of the table the notch on the laser diode case pointsupward and the beam is collimated by the lens. The laser beam should be parallel tothe surface of the optical table. Set the polarizer and quarterwave λ/4 plate in place.Place a mirror after the λ/4 plate and rotate the λ/4 pl ate so that maximum rejectedsignal is obtained from the rejection port of the polarizing beam splitter cube asshown in Figure 1.11. When this signal is maximized the feedback to the laser shouldbe at a minimum.2. Construct the Michelson interferometer as shown in Figure 1.12. Place the beamsteering assembly BSA-II on the optical table and use the reflected beam from themirror to adjust the quarterwave plate orientation. Set the cube mount CM on theoptical breadboard place a double sided piece of adhesive tape on the mount and putthe nonpolarizing beam splitter cube 05BC16NP.6 on the adhesive tape. Next placethe other beam steering assembly BSA-I and the detector mountM818BB inlocation and adjust the mirrors so that the beams reflected from the two mirrorsoverlap at the detector. When long path length measurements are made the interferometer signal willdecrease or disappear if the laser coherence length is less than the two wayinterferometer path imbalance. If this is the case shorten the interferometer until thesignal reappears. If this does not work then check the laser for single-mode operationby looking for the fringe pattern on a card or by scanning the piezoelectric transducerblock PZBin BSA-II and monitoring the detector output which should be sinusoidalwith PZB scan distance. If the laser does not appear to be operatingsingle-moderealign the isolator and/or change the laser operating point by varying the bias current.Additionally to ensure single-mode operation the laser should be DC biased abovethreshold before applying AC modulation. Overdriving the laser can also force it intomultimode operation.3. The Michelson interferometer has the property that depending on the position of themirrors light may strongly couple back toward the laserinput port. In order to furtherreduce the feed-back slightly tilt the mirrors as illustrated in Figure 1.13. If stillunable to obtain single-mode operation replace the laser diode.4. Place a white card in front of the detector and observe the fringe pattern with theinfrared imager. Slightly adjust the mirrors to obtain the best fringe pattern. Try toobtain one broad fringe.5. Position the detector at the center of the fringe pattern so that it intercepts no morethan a portion of the centered peak.6. By applying a voltage to the piezoelectric transducer block attached to the mirrorpart PZB in one arm of the interferometer i.e. BSA-II maximize the outputintensity. The output should be stable over a time period of a minute or so. If it is notverify that all components are rigidly mounted. If they are then room air currents maybe destabilizing the setup. In this case place a box cardboard will do over the setupto prevent air currents from disturbing the interferometer setup.7. Place the interferometer in quadrature point of maximum sensitivity betweenmaximum and minimum outputs of the interferometer by varying the voltage on thePZB.8. The output signal of the interferometer due to frequency shifting of the laser isgiven by I∝φ 2π/c L ν where L is the difference in path length b etween thetwo arms of the interferometer and ν is the frequency sweep of the laser that isinduced by applying a current modulation. Remember that in a Michelsoninterferometer L is twice the physical difference in length between the arms sincelight traverses this length difference in both directions. L values of 3-20 cmrepresent convenient length differences with the larger L yielding higher outputsignals. Before we apply a current modulation to the laser note that the interferometeroutput signal I should be made larger than the detector or laser noise levels byproper choice of L and current modulation amplitude di. Also recall from Section1.3that when the diode current is modulated so is the laser intensity as well as itsfrequency. We can measure the laser intensity modulation by blocking one arm of theinterferometer. This eliminates interference and enables measurement of the intensitymodulation depth. We then subtract this value from the total interferometer output todetermine the true dI/di due to frequency modulation. Apply a low frequency smallcurrent modulation to the laser diode. Note that when the proper range is beingobserved 1 dv 10 5 mA 1 v diand 1 dI 0.2mA 1 I difor the amplitude change only.RecallingdI d(Δφ)2π Δv c dI ∝ΔL 10 5 mA 1 di di cΔi 2πΔLv diordI ΔL 2Kπ mA 1di λ10 -5where K is a detector response constant determined by varying L.9. With the interferometer and detection system properly adjusted vary the drivefrequency of the laser and obtain the frequency response of the laser Figure 1.4 or1.10a.You will need to record two sets of data: i the modulation depth of theinterferometer output as a function of frequency and ii the laser intensitymodulation depth. The difference of the two sets of collected data will provide anestimate of the actual dI/di due to frequency modulation. Also note that if the currentmodulation is sufficiently small and the path mismatch sufficiently large the laserintensity modulation may be negligible. You may need to actively keep theinterferometer in quadrature by adjusting the PZB voltage. Make any necessary function generator amplitude adjustments to keep thecurrent modulation depth of the laser constant as you vary the frequency. This isbecause the function generator/driver combination may not have a flat frequencyresponse. The effect of this is that the current modulation depth di is not constant andvaries with frequency. So to avoid unnecessary calculations monitor the current.。
基于FPGA的光电倍增管APD偏压控制电路设计
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激光测距发射电路的设计
激光测距发射电路的设计周宇;张国平;徐洪波;葛镜;罗俊【摘要】为了激光测距发射电路的集成化要求,设计了一种小型半导体激光器驱动电源,该驱动电源可以用于激光测距中.驱动电路采用MAX3656集成电路作为核心元件,可以通过调节电路中电阻的阻值设置所需要的调制电流和偏置电流.半导体激光器的输出可以直接通过数字电路产生的信号控制,可以输出上升沿时间约为4 ns、脉冲宽度为8 ns的脉冲,这些特性可以用于脉冲激光测距中.%In order to integrate the laser ranging transmitting circuit , a kind of small driver for semiconductor laser is designed, which can be used in laser ranging. Driving circuit uses the MAX3656 integrated circuit as a core component , which can be set by adjusting the resistance of circuit resistance required modulation current and bias current. . Semiconductor laser output can be directly control by the signal of digital circuits. The current can output pulse that the time of rising edge is about 4 ns , and the depends is 8ns, these features can be used in pulse laser ranging.【期刊名称】《电子设计工程》【年(卷),期】2017(025)003【总页数】4页(P145-148)【关键词】激光测距;驱动电路;激光脉冲【作者】周宇;张国平;徐洪波;葛镜;罗俊【作者单位】华中师范大学物理科学与技术学院,湖北武汉 430079;华中师范大学物理科学与技术学院,湖北武汉 430079;华中师范大学物理科学与技术学院,湖北武汉 430079;华中师范大学物理科学与技术学院,湖北武汉 430079;华中师范大学物理科学与技术学院,湖北武汉 430079【正文语种】中文【中图分类】TH74自激光问世以来,激光测距是激光最早的应用领域之一[1-2]。
APD偏压电路的最佳设计
[9]吕华,汪日.《红外和激光工程》.2002年,31:44.
[10]缪家鼎,许文娟,谋同慎.《光电技术》.杭州:浙江大学出版社.1987年,141-142.
[11] Yi-Ren Lai and Pie-You Chien, Method and apparatus forreducing the noise in the receiver of a laser range finder, U.S. Patent:5, 946 , 081, Aug.31,1999.
APD偏压电路的最佳设计
孙纯生,秦世桥,王兴书,朱冬华
1.国防科技大学光电科学与技术学院,中国长沙410073
2.海军工程大学装备工程部,中国武汉430033
本文提出了一种基于温度补偿和负载电阻补偿的雪崩光电二极管(APD)反向偏压控制方法,并详细的分析了背景光和负载电阻对雪崩光电二极管检测电路的影响。为雪崩光电二极管偏置电路的设计建立了一种理想的温度补偿和负载电阻补偿模型。据预测,这种控制方法特别适用于车辆使用的激光测距仪。实验结果证实,本文提出的设计可以很大程度的改善测距仪的性能。
[12] I-Jen Lai, Pi-Yao Chien, and Chih-Wei Hung, Light receivingcircuit of laser range finder, U.S. Patent: US2002/0033937 A1, Mar. 21, 2002.
本文译自:OPTOELECTRONICS LETTERS.Vol.3 No.3, 15 May 2007
从以上理论分析和实验结果,我们发现基于负荷电阻的温度补偿和背景光补偿的APD偏压控制方法可以大大地提高相同条件下APD检测电路的检测能力范围和抗背景光能力。这种方法的电路设计特点是结构简单,成本低,所以它是一个实际可行的项目。
一种应用于脉冲激光测距系统的宽动态-高速接收电路
一种应用于脉冲激光测距系统的宽动态-高速接收电路王强;孙志慧;倪家升;刘永宁;张燕;魏巍;常军【摘要】为提高脉冲激光测距系统的测距精度,采取对APD偏压和放大器增益双重控制的方法设计了一种用于脉冲激光测距系统中的接收电路。
模拟仿真结果表明,此电路能接收80dB宽动态范围的回波功率,实现了0.5—2V的有效电压输出,仿真得到此电路的有效带宽为58MHz。
测试结果表明此设计有效可行。
%We design a receiving circuit for a pulse laser rangefinder with the control over bias voltage of APD and amplifier gain to improve its range accuracy. Simulation results show that the circuit can receive greater echo power of dynamic range of 80 dB and implement output voltage of 0. 5 - 2 V and valid bandwidth of .58 MHz. Test results demonstrate that the design is feasible.【期刊名称】《山东科学》【年(卷),期】2012(025)002【总页数】6页(P53-58)【关键词】脉冲激光测距系统;接收电路;宽动态回波功率;高速脉冲【作者】王强;孙志慧;倪家升;刘永宁;张燕;魏巍;常军【作者单位】山东省科学院激光研究所,山东济南250014/山东大学信息科学与工程学院,山东济南250100;山东省科学院激光研究所,山东济南250014;山东省科学院激光研究所,山东济南250014;山东大学信息科学与工程学院,山东济南250100;山东大学信息科学与工程学院,山东济南250100;山东大学信息科学与工程学院,山东济南250100;山东大学信息科学与工程学院,山东济南250100【正文语种】中文【中图分类】TN958.98作为一种可以快速获取目标精确距离信息的有效手段,高精度脉冲激光测距在诸如大地的测绘测量、对远距离目标的精确打击、工业现场非接触测量、航天器交会对接等领域都获得了广泛应用。
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APD偏压电路的最佳设计孙纯生,秦世桥,王兴书,朱冬华1 .国防科技大学光电科学与技术学院,中国长沙4100732 . 海军工程大学装备工程部,中国武汉430033本文提出了一种基于温度补偿和负载电阻补偿的雪崩光电二极管(APD)反向偏压控制方法,并详细的分析了背景光和负载电阻对雪崩光电二极管检测电路的影响。
为雪崩光电二极管偏置电路的设计建立了一种理想的温度补偿和负载电阻补偿模型。
据预测,这种控制方法特别适用于车辆使用的激光测距仪。
实验结果证实,本文提出的设计可以很大程度的改善测距仪的性能。
雪崩光电二极管(APD)的特点是具有很高的量子效率和教大的内部增益,这可以很大程度的降低对前置放大电路性能的要求,并能提高检测电路的信噪比(SNR)。
因此,它具有很广泛的用途,如光纤通信、激光测距仪、微弱信号探测器等。
为了使检测电路能获得最佳检测性能,APD的外部电压需要接近最佳倍增因子时的电压。
由于最佳倍增因子是许多因数的复函数,如:外部温度、背景光通量、放大器噪声和系统带宽,因此需要设计一个复杂的反馈控制电路及时的调整雪崩光电二极管的偏压。
当然这就增加了开销。
本文介绍了一种简单的、避免高开销的方式,就是确保温度补偿的同时给APD偏置电路选择一个合适的负载电阻。
通过这种方式,背景光对雪崩光电二极管检测电路造成的不良影响可在一定程度上得到补偿,并且检测电路抗背景光能力得到了改善。
在这种方法基础上为汽车防撞设计的激光测距仪能很好地满足系统的要求。
APD激光检测电路的主要噪声源包括检测器噪声、负载电阻噪声、放大电路前端噪声,还有背景光电流和信号光电流造成的散粒噪声。
当前的信噪比可以按照下列方程式计算:(1)方程1右边分子部分是光信号电流。
方程1右边分母部分是噪声电流,包括三个方面。
第一项是背景光电流和信号光电流造成的散粒噪声,第二项是检测器噪声,最后一项是负载电阻噪声和跟随放大电路的等效噪声。
在方程中,s P 代表检测器接收到的光信号功率,M 是APD 的倍增增益,o R 是当M=1时的电流灵敏度,e 是电子的电荷量,等于1.602×10-19C ,B 是检测电路的通频带宽,b P 是检测器收到的背景光功率,A F 是APD 的过量噪声系数,ds i 是APD 表面漏电流,db i 是负载漏电流,K 是玻耳兹曼常数,等于1.3807 × 10-23 JK-1,T 是检测器负载电阻的温度(K),l R 是检测器的负载电阻(Ω),n F 是放大电路的等效输入噪声系数。
由于实际使用中M 是远远大于1的,暗电流可表示为d i ≈M db i ,而APD 过量噪声因子A F =kM +(1-k )(2-1/M )≈2+kM 。
在这一近似条件下,当d (i SNR )/dM =0,i SNR 达到其最大值且倍增因子达到最佳,可表示为:(2)方程2中符号和方程1中符号的含义相同。
我们知道,最佳倍增因子是外部温度、光信号功率、背景光功率,APD 噪声、光谱灵敏度、放大器噪声和系统带宽的函数。
此外,特别是APD 内部结构决定了其倍增增益M 随工作温度变化而变化。
用温度系数T C 来描述这种影响。
对于C30737系列的APD ,T C 为 0.6 V/℃,这意味着在相同条件下,当APD 的工作温度增加1℃,为了维持APD 倍增因子不变偏压需要增加0.6 V 。
从前面一段的分析,我们知道,电路温度和背景光补偿旨在控制偏压,以便在不同SNR温度和背景光条件下电路仍能保持最佳的APD 倍增因子。
目前有几种偏置电路控制方法:恒流偏置,温度补偿和恒虚报警控制。
恒流偏置是只适用于不变的背景光或无背景光情况。
温度补偿抗背景光的能力较差。
恒虚假控制可以保持最佳的倍增因子,但复杂的电路和高成本才换来较高的性能。
本文提出了一种新方法,为APD 偏压电路设计了温度补偿以及串行电阻背景光补偿,实现高性能的同时保持低成本。
温度变化对APD 偏置电路的影响主要在两个方面:一是温度变化使负载电阻噪声发生变化,因而改变了APD 检测电路的最佳增殖因子;另一方面,温度变化改变了APD 载流子和晶格之间的碰撞频率和强度,这也改变了APD 的倍增因子。
以下就是分析这两个因数的影响。
APD 倍增因子M 和其反向偏置电压V 之间的关系可以用下式描述:(3)其中V 是APD 的反向偏置电压,B V 是某一确定温度时的击穿电压,n 介于1和3之间,它由半导电材料、半导体掺杂分配和辐射源的波长决定。
在方程3中,当M 达到最佳值opt M 时反向偏置电压达到最佳opt V 。
从方程2和3我们能够得到最优偏置电压opt V 、工作温度和接收到的背景光功率b P 之间的关系如下:(4)方程4只包括APD 偏置电路的温度对负载电阻噪声的影响,例如上文提到过的一个方面。
温度变化对APD 倍增因子影响可表示为温度系数t C 。
以最佳工作电压22V 为22℃作为参考点,温度变化引起的最佳偏置电压的变化可以描述为: (5)方程5右边前面两项的和Δ1V 表明负载电阻噪声对最佳偏置的影响。
方程5右边第三个项Δ2V 表明工作温度对APD 偏置的影响。
公式5显示了当温度变化时如何控制偏置电压优化倍增系数。
这仅仅是APD 偏置电压工作的温度补偿模型。
从方程5,我们知道ΔV 不仅取决于APD 的工作温度T ,而且还取决于击穿电压B V 、接收光信号功率和背景光功率。
因此,方程5是不符合实际工程的。
实际中,Δ2V >>Δ1V ,所以方程5可以近似为: V (6)APD 的温度系数(用t C 表示)和22 ℃时的最佳工作电压可在设备手册里获得,工作温度可用温度传感器测出。
因此,APD 偏压相对于22V (22V 由于温度变化而造成的)的补偿可通过方程6得到。
温度补偿由模拟温度传感器、模拟数字转换A / D 转换器、微控制器和可调直流电源供应(DC )电路组成,其电路框图如图1所示:图1.温度补偿电路原理图模拟温度传感器置于APD 附近监测其工作温度。
A / D 转换器将模拟温度信号变量转换成数字信号变量。
单片机的作用是将A/D 转换器提供的数字温度信号转变成相应的控制信号,并根据方程6和控制方程调整数字电位器的输入电阻值调整直流电源供应。
通过调整输入电阻值来调整直流适配器,这样就能输出合适的APD 偏压。
温度补偿、背景光补偿可以通过适当选择的负载电阻实现。
因此检测电路的抗背景光干扰能力可以大大改善。
图2显示了APD 检测电路的偏置电路及其外围电路,其中0V 是温度补偿后输入的可调的直流电压,π型滤波器由电容1C 、2C 和电阻C R 组成,输出脉冲信号的读出电路由电容3C , 电阻f R 和运算放大器V A 组成。
l R 是APD 偏压电路的直流负载电阻。
我们将在下面分析APD 偏压电路负载电阻(C R )对抗背景光能力的的影响。
从图2,我们知道,APD 偏置电压的性能可表示为:图2.APD 的外围电路V (7)由方程3和7,偏置电压apd V 、背景光功率b P 和负载电阻C R 间的关系可以表示为: (8) 基于温度补偿,并假设只考虑背景光功率b P 对APD 最佳偏置电压opt V 的影响,opt V 和b P 之间的关系给出如下:(9) 如果方程8中工作电压等于方程9的最佳值,温度补偿后APD 获得最佳倍增因子,检测电路信噪比也能达到最高水平。
为了检查上述方法的有效性,我们在汽车半导体激光测距仪设计中运用此方案,并设定具体参数来检测150米远的目标。
如图3所示,APD 偏压apd V 、背景光功率和串行电阻C R 之间的关系可通过对方程8和9进行数值计算和分析得到。
通过同样的方式,如图4,检测电路当前的i SNR 、背景光功率和串行电阻C R 之间的关系可以通过方程1、8和9得到,这里s P =30 nW, 0R =0.35, B =35 M, b P =0~500nW 。
在背景光较弱时,b P =200nW, db i =8×10-11A, k =0.02, l R =400 Ω, n F =1, B V =158.6 V, 0V =0.95 V B.图3显示了c R 取不同值时APD 偏压和的背景光之间的关系,其中实线代表最佳偏压opt V 和背景光之间的关系,虚线代表工作偏压apd V 和背景光之间的关系。
该图显示了opt V 和apd V 随着c R 变化的补偿。
因而可以找到一个最佳的c R 使opt V 和apd V 保持一致。
图4对应于图3,显示了c R 取不同值时检测电路当前SNR 和背景光之间的关系,其中实线呈现了最佳SNR 和背景光间的关系,虚线显示了c R 取不同值时实际SNR 和背景光间的关系。
该图显示了APD 检测电路和最佳偏压因c R 不同而产生不同的偏移时的实际SNR 。
为了优化检测电路的性能,认真选择c R 对保持实际SNR 和最佳SNR 恒等非常重要。
从图3和4,我们知道背景光对检测电路造成的不良影响可以通过选择合适的c R 得到一定的补偿,并能够改善检测电路的性能。
图3.()c s R 不同时apd V 和b P 间的关系 图4.()c s R 不同时i SNR 和b P 间的关系这种雪崩光电二极管激光检测电路已广泛地运用于汽车防撞激光测距仪中,其性能测试的方法有两种。
途径之一是在恒定的背景光下改变雪崩光电二极管的负载电阻,这时激光测距仪测距能力范围变化很明显。
在明亮的背景光下,c R 为1.1M Ω时的测量范围比c R 等于5 M Ω或100 k Ω的范围大10 %~20 %左右。
另一种方式是在相同的测量范围下改变APD 负载电阻,这时测量的抗背景光干扰能力具有明显的差距。
在同一测量范围,c R 为1.1M Ω对比c R 等于5 M Ω或100 k Ω抗背景光能力增加了20 %~30 %。
从以上理论分析和实验结果,我们发现基于负荷电阻的温度补偿和背景光补偿的APD 偏压控制方法可以大大地提高相同条件下APD 检测电路的检测能力范围和抗背景光能力。
这种方法的电路设计特点是结构简单,成本低,所以它是一个实际可行的项目。
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