高精度半导体激光器温控系统的设计与实现

为了使半导体激光器辐射波长和发光强度的稳定性不受环境温度的影响,设计了一款高精度半导体激光器温控系统。采用AD620和LTC1864芯片设计了温度采集电路,用MAX1968和LTC1655设计了温度控制电路,而用TMS320F2812实现对整个系统的精确控制;提出了自适应模糊比例-积分-微分控制策略并完成了软件实现。在环境温度约15℃时,分别设定25℃和20℃进行试验,温度控制精度达±0.05℃。结果表明,该温控系统响应速度快、稳定性高。     

通信用大功率半导体激光器的温控系统

温控系统在半导体激光器运行中具有重要作用,基于温度控制技术主要应用在DFB结构中,其原理在于调整激光腔内温度,从而可以使之发射不同的波长。文章首先概述了通信用大功率半导体激光器温控系统,进而分析了两种开发模式。     

基于数字滤波的半导体激光器温控系统设计

为了使光收发模块发射光波长稳定,突破现有半导体激光器温控系统大都采用模拟器件实现的常规设计,提出了一种基于数字滤波方式的控制方案,采用数字信号处理方式,以固件形式实现了半导体激光器温度控制。通过理论分析和实验验证,取得了采用该方案的光收发模块在应用温度范围内的发射波长变化数据。结果表明,该系统性能稳定,温度控制精度达0.053℃。     

半导体激光器驱动及温控系统研究

体积小、重量轻、稳定性高的特点,使半导体激光驱动器在许多领域都有广泛的应用,而且在未来仍具有突出的发展前景。本文就半导体激光器驱动及温控系统进行研究,首先介绍了半导体激光器恒流驱动的整体设计以及驱动电路设计,再针对温控系统的系统方案设计和温控硬件系统设计进行简要介绍。     

大功率半导体激光器驱动电源及温控系统设计

为了解决大功率半导体激光器的输出波长和功率的稳定性问题,设计了一套大功率激光器恒流驱动电源及温控系统。利用深度负反馈电路实现对激光器驱动电流的恒流控制,采用硬件比例-积分（Proportional-Integral,PI）温控电路结合恒流驱动,控制半导体制冷器（Thermoelectric Cooler,TEC）的工作电流,实现激光器工作温度的精确控制。所设计的驱动电源可实现输出电流0~12.5 A连续可调,同时具有电流检测、过流保护、晶体管-晶体管逻辑（Transistor-Transistor Logic,TTL）信号调制等功能。所设计的温控系统的控制精度可达到0.05℃,同时设定温度连续可调,温度可实时监测。实验结果表明该设计能够保证稳定的电流输出和温度控制,满足大功率激光器的使用要求。     

半导体激光器高精度稳频输出控制系统

为了在光纤干涉仪中得到光源高精度稳频输出,采用高稳定度的恒温控制以及功率稳恒控制方法,通过高信噪比的运算放大器、半导体制冷器,设计了一种激光电源驱动系统,并进行了理论分析和实验验证。其能为半导体激光器提供温度控制精度在±0.01℃,制冷驱动电流可达800mA,同时使得半导体激光器输出波长控制精度在±0.1nm,驱动电流最大输出可达180mA,输出电流的稳定度为10-4~10-5。结果表明,该系统不仅结构简单,而且温度控制稳定、准确度高,可使半导体激光器的输出波长保持稳定,保证了干涉型光纤传感器的测量准确度以及在通信领域中的应用。     

TEC 的高精度半导体激光器温控设计

热电制冷器（TEC）作为半导体激光器（LD）的制冷方案,具有体积小、易于控制等优点。但基于TEC 的制冷方案中TEC 的制冷功率和目标散热功率之间需要有良好地匹配关系,否则将会导致制冷不足或者导致功耗过大。根据LD 组件热负载匹配TEC 制冷功率,并通过比例-积分-微分（PID）控制方法实现温控参数的优化设计,实现了基于TEC 的LD 温度控制系统。经实验验证:该系统能够对LD 的工作温度实现控制范围为5℃~41℃、稳态误差小、控制精度为0.05℃的高精度、高稳定性控制,并在高精度的波长测试中得到了很好的应用。     

半导体激光器的高精度温控仪

温度对半导体激光器的特性有很大的影响.在要求半导体激光器输出波长稳定的情况下,必须对其温度进行高精度的控制。本文利用高信噪比的运算放大器和普通的负温度系数温度传感器及半导体致冷器做控温元件,研制了一种用于半导体激光器温度控制的高精度温控仪,控制精度可达±0.05℃.     

大功率半导体激光器驱动电源的设计

设计一种大功率半导体激光器的驱动电源。恒稳电流范围为 0～ 10 A,稳流精度为 1m A,脉冲输出电流频率为 10 KHz,脉冲电流的占空比为 1∶ 10 ,脉冲电流幅值为 0～ 10 A可调     

高精度半导体激光器驱动电源及温控电路设计

为了解决布里渊光纤传感系统中半导体激光器光源输出功率和波长易受驱动电流和温度影响的问题,设计了一种高精度恒流驱动和温控电路。该电路利用深度负反馈积分电路对激光器驱动电流进行精密的恒流控制,同时采用集成温度控制芯片MAX1978控制半导体制冷片的工作电流,实现对激光器工作温度的精确控制。结果表明,本设计实现了驱动电流0mA~100mA可调,电流控制最大相对误差为0.06%,电流稳定度为0.02%,温度控制最大误差为0.03℃,在温控的条件下,光功率稳定性达到0.5%,最大漂移量为0.005dBm。该设计实现了对电流和温度的有效控制,保证了输出光的稳定性。     

Dual-thermistor temperature control for semiconductor lasers

A technique using two thermistors for maintaining junction temperature of a laser diode over a wide current range is proposed. The wavelength of a 980 nm module was stabilised within 1 nm with this technique from 25 to 400 mA. compared to a wavelength shift of 5 nm with traditional one-thermistor control.     

基于DRV595的激光器恒温控制系统

半导体激光器的输出波长和功率随温度变化而变化,为了确保激光器工作性能,须对其进行恒温控制。采用脉冲宽度调制功率驱动器DRV595驱动半导体制冷器的方法,设计了一种双向大电流输出的高精度温度控制系统。在S域对系统进行了建模分析,搭建经典比例-积分-微分控制器,采用桥式采样电阻,纯硬件电路实现,结构简单,省掉了数字控制器的复杂软件编写。在常温试验中取得了±0.03℃的控制精度,DRV595集成脉冲宽度调制和双向MOSFET,输出电流最大为±4A。双向电流驱动半导体热电制冷器,实现了无死区控制。结果表明,脉冲宽度调制方式驱动和低输出级电阻大大降低了功率耗散。该系统工作稳定、功耗低、控制精度较高,具有实用价值。     

面阵半导体激光器的耦合理论设计

用光线追迹方法计算了面阵半导体激光器的光束在透镜导管内传播及分布情况。理论给出了设计透镜导管时主要考虑的参数及其选取原则,在输出平面上得到了近高斯分布的激光输出,理论表明,利用透镜导管对面阵半导体激光器进行耦合能够获得高功率密度的光束输出,这种方法将是今后高功率全固态激光器耦合系统的主要耦合方法。     

High-order diffraction gratings for high-power semiconductor lasers

A deep diffraction grating with a large period (∼2 μm) within one of the cladding layers is proposed for the implementation of selective feedback in a semiconductor laser. Frequency dependences of reflectance in the 12th diffraction order for rectangular, triangular, and trapezoidal diffraction gratings are calculated. It is shown that the maximum reflectance of the waveguide mode is attained using a rectangular or trapezoidal grating ∼2 μm deep in the laser structure. Deep trapezoidal diffraction gratings with large periods are fabricated in the Al_0.3Ga_0.7As cladding layer of a GaAs/AlGaAs laser structure using photolithography and reactive ion etching.     

可调谐半导体激光器的精密控制系统设计

为了满足高精密测量领域对半导体激光器高稳定度的要求,设计了一种高稳定度、低噪声的半导体激光器控制系统。该控制系统由电流驱动和温度控制两部分组成,电流控制部分采用负反馈控制保持电流稳定,温度控制部分采用高度集成的MAX1978作为主控芯片,驱动半导体制冷器进行温度补偿。经过实验验证,电流在200mA范围内连续可调,电流控制精度高达1A,在3kHz~100kHz带宽内交流噪声有效值小于300nA,长期温度漂移小于2m℃。结果表明,该系统可用于驱动分布式反馈外腔半导体激光器和分布式布喇格反射半导体激光器。     

Quantification of thermoreflectance temperature measurements in high-power semiconductor devices—lasers and laser bars

In this paper we present results of the analysis of the thermoreflectance (TR) measurements performed on the high-power laser diodes and laser bar emitting at 808 nm. TR is a modulation technique relying on periodic facet temperature modulation induced by pulsed current supply of the laser. The periodic temperature change of the laser induces variation of the refractive index and consequently modulates probe beam reflectivity. Spatially resolved TR spectroscopy is applied to measure line-scans and maps of temperature distribution at the laser mirrors and emitter facets in laser bar. However, to get the absolute values of temperatures, TR needs calibration. Different calibration methods, such as μ-Raman spectroscopy and in situ determination of TR coefficient (C_TR), will be discussed. The knowledge of temperature distribution at laser facets gives insight into thermal processes occurring at devices’ facets and consequently leads to the increased reliability and substantially longer lifetimes of such structures.     

A metallization scheme for junction-down bonding of high-power semiconductor lasers

High-power semiconductor lasers have found increasing applications in industrial, military, commercial, and consumer products. The thermal management of high-power lasers is critical since the junction temperature rise resulting from large heat fluxes strongly affects the device characteristics, such as wavelength, kink power, threshold current and efficiency, and reliability. The epitaxial-side metallization structure has significant impact on the thermal performance of a junction-down bonded high-power semiconductor laser. In this paper, the influence of the epitaxial-side metal (p-metal) on the thermal behavior of a junction-down mounted GaAs-based high-power single-mode laser is studied using finite-element analysis. It is shown that a metallization structure with thick Au layer can significantly reduce the thermal resistance by distributing the heat flow to wider area laterally, and the thermal resistance of a junction-down bonded laser with thick Au metallization is much less sensitive to the voiding in the die attachment solder interface than a laser with thin Au metallization. A metallization structure of Ti-Pt-thick Au-Ti-Cr-Au is designed and implemented, and the metallurgical stability of this metallization scheme is reported. It was found that, without a diffusion barrier, the thick Au layer in the epi-side metallization would be mostly consumed and form intermetallics with the Sn from the AuSn solder during soldering and thermal aging. The Ti-Pt-thick Au-Ti-Cr-Au metallization scheme prevents the diffusion of Sn into the thick Au layer and preserves the integrity of the metallization system. It is a promising candidate for junction-down bonding of high-power semiconductor lasers for improved thermal management and reliability.     

Optimized cooling systems for high-power semiconductor devices

Straightforward air cooling of semiconductor devices has gradually been replaced by methods using liquid coolants, especially water cooling. In this paper, more advanced cooling devices for hockey-puck-type and module-type semiconductors are suggested. An established heat sink made of aluminum nitride for the water cooling of hockey-puck-type semiconductors has been used as a basis for the development of high-performance heat sinks for increased heat flux densities. By means of thermal and fluid dynamics simulation tools the internal geometry has been optimized with regard to improved heat transfer and reduced pressure drop. The simulation results have been confirmed by a number of experiments using various measuring techniques. As an alternative cooling method for semiconductor modules, a modified baseplate comprising a number of fins for direct water cooling has been suggested. For an intelligent temperature management control algorithms have been developed, resulting in a prototype application-specific integrated circuit which has been implemented for test purposes     

Wavelength sensed mode control of semiconductor lasers

A wavelength detector suitable for use with semiconductor laser packages has provided control of laser emission wavelengths to better than 0.1 ?. Special features of the detector have also enabled mode hopping, gain profile shift and end of single-mode lifetimes to be observed.