Optimized design of laser range finding system using the self-mixing effect in a single-mode VCSEL

An optimized design of laser range finding system using the self-mixing effect in a single-mode vertical-cavity surface-emitting laser (VCSEL) is proposed. In order to improve the ranging accuracy and expand dynamic measurement range, we apply difference frequency analog phase-locked loop (PLL) instead of fast Fourier transform (FFT) to process signal, and choose the optimum triangular wave frequency fm = 500 Hz and small modulation current △Ip-p = 0.28 mA to modulate single-mode VCSEL. The experiment results show that, without controlling the laser's temperature, the ranging accuracy is better than 2 mm and the measurement dynamic range is as large as 50-500 mm when the sampling time is 0,1 s and the room temperature is 0-55℃.     

Effect of speckle pattern on laser Doppler velocimeters

The effect of speckle pattern on laser Doppler velocimeters is studied theoretically and experimentally. We have found that dynamic speckle patterns can cause error in velocity measurement. Increasing sampling time and using proper signal processing circuits can eliminate this bad effect caused by speckle pattern. The accuracy of velocity measurement is better than 2.1% in a wide velocity range (4.66-468.86 mm/s) when speckle effects are taken into account.     

Costas环单片集成电路

介绍了多功能单片集成Ｃｏｓｔａｓ环ＫＤ８２的电路、版图和工艺设计方法。     

高精度宽测速范围精确方向判别单模VCSEL自混合LDV

单模VCSEL(Vertical cavity surface emitting laser)激光器自混合LDV(Laser Doppler veloci-tymeter)系统的温度特性和外腔长度Lext(激光器前腔镜到目标散射面之间的光程)可变范围优于多模激光器LDV系统.应用差频模拟锁相环信号处理技术,明显提高了单模VCSEL自混合LDV测速精度和测速动态范围.用多普勒频移,fd的分频跟踪三角波电流调制技术,提高了运动方向判别的精度和动态范围.实验结果表明,在外腔长度为30 mm±3 mm、温度为0℃～55℃、采样时间0.1 s、激光器无温控的条件下,分辨率优于0.2%;在测速范围为30～480 mm/s的条件下,测速精度优于1%;在速度范围为5～480 mm/s的条件下,测速精度优于2%.在电源电压为5 V时,正向运动方向指示电平大于4.9 V,反向运动方向指示电平小于0.1 V.     

半导体DFB激光多波长锁定器

密集波分复用 (ＤＷＤＭ )技术是扩大光纤通信传输容量的有效途径 ,国际通信联盟 (ＩＴＵ )规定了光纤中光载波信道间距为 10 0ＧＨｚ或 5 0ＧＨｚ ,相应的波长间距分别为 0 8ｎｍ和 0 4ｎｍ ,这便要求各信道上的ＤＦＢ激光器的波长有较高的稳定度 ,例如波长漂移 <2ＧＨｚ。     

激光线宽展宽因子对半导体激光自混合信号影响的研究

采用数值模拟法获得了自混合信号的时域特性,并在此基础上对激光器重要参量线宽展宽因子在混合信号中的影响进行了数值模拟和分析,得出了采用较大线宽展宽因子的激光器可以获得幅度较大以及较强的不对称自混合信号的结论.     

面发射半导体激光器自混合振动测量实验研究

采用新型垂直腔面发射激光器(VCSEL)作为激光自混合振动测量系统的激光光源,针对不同驱动信号频率(1 kHz,2 kHz)、驱动信号幅度(880 mV,1.66 v)的振动驱动信号对激光自混合振动测量信号系统进行实验研究,并与通过激光稳态方程所获得的激光自混合振动信号仿真进行了比较分析.结果表明,2 kHz相对1 k...     

Coarse error analysis and correction of a two-dimensional triangulation range finder

A real-time two-dimensional (2D) triangulation range finder is presented, which is composed of two linear complementary metal oxidation semiconductor (CMOS) chips, two camera lenses, and four light emitting diodes (LEDs). The high order distortion in image aberrations is the main factor responsible for the coarse errors. The theoretical prediction is in good agreement with experiments and the correction equation is used to obtain more reliable results with the unique distortion coefficient in the whole working region.     

半导体DFB激光多波长锁定器

密集波分复用(DWDM)技术是扩大光纤通信传输容量的有效途径,国际通信联盟(ITU)规定了光纤中光载波信道间距为100GHz或50GHz,相应的波长间距分别为0.8 nm和0.4 nm,这便要求各信道上的DFB激光器的波长有较高的稳定度,例如波长漂移<2 GHz。     

时分副载波半导体DFB激光多路波长锁定器

我们研制成功8路时分副载波半导体DFB激光器波长锁定器.用1kHz正弦时分电信号,分别对8个1.55μm波段的DFB激光器进行1％的幅度调制,每个DFB激光2％的光信号分成两路,一路通过自由光谱区为100 GHz的F-P标准具,另一路作参考光,两路的光电差分信号反馈控制DFB激光器的温度,使每个DFB激光器锁定在各自所需的波长上.测试结果表明波长锁定的激光频率间隔100 GHz,波长锁定精度优于±2.5GHz。该方法同样适用于50GHz频率间隔和更多路的波长锁定.本文着重介绍该锁定器的光电信号处理和控制方法.