高速近红外1550nm单光子探测器

高速近红外1 550 nm单光子探测器采用半导体制冷和热管风冷混合技术,雪崩二极管工作于盖革模式下,使用交流耦合方式提供门脉冲信号,通过延迟补偿和采样边沿锁存方式消除尖脉冲干扰,采用反馈门控减小后脉冲的影响。采用了ECL(Emitter Couple Logic)与TTL(Transistor-TransistorLogic)混合电子技术提高单光子探测系统的运行频率,其频率可大于10 MHz;另外,通过对雪崩信号的放大来提高信号的动态范围,进一步优化探测器的性能。实验测试与分析表明,探测器在时钟频率10 MHz、温度-62℃、门脉冲宽度8 ns的条件下的最优性能参数为:量子探测效率12.8%,暗计数率3.76×10-6ns-1,噪声等效功率8.68×10-19W/Hz1/2。     

pin硅波导在1550 nm波段的光电流雪崩增强效应实验研究

The photocurrent effect in pin silicon waveguides at 1550 nm wavelength is experimentally investigated. The photocurrent is mainly attributed to surface-state absorption,defect-state absorption and/or two-photon absorption.Experimental results show that the photocurrent is enhanced by the avalanche effect.A pin silicon waveguide with an intrinsic region width of 3.4μm and a length of 2000μm achieves a responsivity of 4.6 mA/W and an avalanche multiplication factor of about five.     

General matrix theory of self-imaging in multimode interference(MMI) couplers

We present a simple and very general matrix method for predicting the properties of integrated optical multimode interference (MMI) couplers with single-mode input and output guides. We derive a set of N×N matrices which (in the paraxial limit) can be used to predict the complex mode amplitudes in the output guides from the complex mode amplitudes in the input guides for any type of MMI coupler, splitter or recombiner. We compare this theory with experiment for an 11×11 nonuniform coupler     

用光纤光栅稳定980 nm激光器波长的研究

文章通过将一根弱反馈的光纤光栅连接在无致冷的980 nm泵浦激光器尾纤上,使激光器工作在相干失效状态下,大大改善了无致冷激光器的波长和功率的稳定性.文章根据实验结果分析了光纤光栅的主要参数对激光器输出功率和光谱的影响.通过对光纤光栅参数的优化,可以使无致冷980 nm泵浦激光器在0～70 ℃下稳定工作.     

大功率980 nm LD-FBG多光腔组件波长锁定的研究

文章介绍了980 nm LD-FBG(激光器-光纤布拉格光栅)多光腔组件的组成和工作原理;报告了该组件在不同驱动电流和环境温度下的光谱测试结果;分析讨论了楔型耦合光纤反射率对组件光谱的影响以及波长锁定和结构优化问题.实验表明,当光功率为100~250 mW、环境温度为25~75 ℃时,优化的多光腔组件峰值波长变化＜0.6 nm,边模抑制比>45 dB.     

Low-noise narrow-linewidth fiber laser at 1550 nm (June 2003)

We present a compact integrated fiber laser with more than 200 mW of output power. It combines polarized fiber output with very narrow linewidth of less than 2 kHz. The coherence length of the laser is measured to be longer than 5 km. The laser features high mode stability of less than /spl plusmn/10 MHz over hours. The relative intensity noise (RIN) spectrum is dominated by a peak at the relaxation oscillation frequency and is shot-noise limited otherwise. The RIN peak at 1 MHz is reduced to /spl sim/-130 dB/Hz by integrating a negative feedback circuit. In addition to thermal wavelength tuning, the laser frequency can be modulated at a bandwidth of up to 10 kHz via the piezoelectric effect.     

Single-mode fused biconical couplers for wavelength divisionmultiplexing with channel spacing between 100 nd 300 nm

The authors report on single-mode fused biconical couplers tailored to the requirements of wavelength-division-multiplexing systems. The wavelengths of the two channels can be chosen arbitrarily for wavelength separations between 100 and 30 nm. For separations between 150 and 300 nm, the couplers can be manufactured with an accuracy of ±5 nm at the two operating wavelengths. For decreasing wavelength separation of the channels, the influence of the state of polarization results in an increased inaccuracy of the two wavelengths, increased far-end crosstalk, and power fluctuations after the coupler. This sets a lower limit for channel separation. Good agreement between theory and experiment is achieved     

All-optical 1310 to 1550 nm wavelength conversion by utilising nonlinear polarisation rotation in semiconductor optical amplifier

A 1310 to 1550 nm wavelength converter based on nonlinear polarisation rotation in a single semiconductor optical amplifier is demonstrated. Error-free 1310 to 1550 nm wavelength conversion is shown at 20 Gbit/s.     

Dual-wavelength (1050 nm +1550 nm) pumped thulium-doped fiber amplifier characterization by optical frequency-domain reflectometry

We present experimental results of distributed gain measurements from a dual-pumped (1050 nm +1550 nm) thulium-doped fiber amplifier using optical frequency-domain reflectometry. We show that significant reductions in total pump power and/or fiber length are realized with the addition of a few milliwatts at 1550 nm. For our experimental conditions, the addition of 5 mW of 1550 nm allows for a reduction of 100 mW of pump power at 1050 nm or a reduction of 44% of doped fiber length to reach the same gain as with 1050-nm pumping alone.     

Study of optical output couplers for submillimeter wavelength backward-wave oscillators (BWO's)

The machining of slow wave structures for high frequency BWO's is extremely difficult beyond l THz. Recently a microfabrication technique using photolithography and ion-beam assisted etching has been used to construct a prototype BWO operating at 200 to 265 GHz. The output coupler for such tubes remains a problem. Waveguides do not exist or are very lossy at the frequencies of interest (300 to 2000 GHz). This paper discusses several scaled experiments of optical output couplers for submillimeter BWO's. Various designs of planar antennas (Vivaldi horns) and lens-feed systems (hyperhemispherical lens) were constructed and tested between 20 and 100 GHz using a spectrum analyzer. The lens system was also tested at 337 GHz using a CO₂ pumped FIR laser.     

Short wavelength (699 nm) electrically pumped vertical-cavitysurface-emitting lasers

Room-temperature lasing has been achieved in vertical-cavity surface-emitting laser structures for wavelengths as short as 699 nm under pulsed electrical excitation. The molecular beam epitaxially grown structures have p- and n-type semiconductor quarter wave mirror stacks enclosing an active region containing a short period GaAs-AlAs superlattice     

用于光纤测量的1310nm/1550nm半导体激光驱动电源

为了实现光纤的精确快速测量, 设计了一种高稳定功率连续可调的1310nm/1550nm半导体激光驱动电源。该电源采用电流串联负反馈技术组成精密恒流源驱动半导体激光二极管,恒温控制电路驱动半导体制冷器,从而保证了激光器输出功率的稳定。控制器局域网络总线电路实现激光源的功率连续可调及激光的选择,通过变速积分PID控制算法消除了积分饱和,加速系统温度的稳定。采用激光保护和软启动电路,实现半导体激光器可靠稳定运行。结果表明,半导体激光器工作在室温25℃时,温度稳定性达0.01℃,激光长期输出功率稳定度达0.018dB。相对于传统的1310nm/1550nm半导体激光光源,该光源稳定性高、稳定速度快、体积小,方便光纤在线测量。     

烟雾环境中532 nm/1550 nm线偏振光前向传输实验研究

针对烟雾环境中偏振前向传输在短波红外波段是否具有偏振信号增强的问题,实验研究了烟雾环境中水平线偏振光在532 nm和1 550 nm波长下的前向传输偏振特性。烟雾环境由烟饼燃烧所制,其主要由悬浮氯化铵颗粒和水汽组成,且氯化铵颗粒在烟饼点燃7~16 min内稳定沉积。搭建了532 nm和1 550 nm两套单波长激光前向传输测试平台,用以测量水平线偏振光在烟雾环境中的前向传输偏振特性。分析测量误差主要由激光源的光强波动误差、测量时间变化误差、偏振器件的安装误差和转角误差引起,计算了532 nm和1 550 nm激光前向传输测试平台的测量误差峰值分别约为1.03%和0.89%。测试烟饼燃烧7~16 min时的偏振状态保持率RoPS,测试结果表明:相比532 nm波长,水平线偏振光在1 550 nm波长前向传输后具有更优异的偏振状态保持特性,且随着烟雾浓度降低,两者之间的偏振状态保持差异逐渐缩小。文中研究通过实验验证了所制烟雾环境中水平线偏振光在1 550 nm波长前向传输后具有优异的偏振信号,这可为短波红外偏振技术的实际应用提供一定的实验支撑。     

High-power lasers (λ = 940–980 nm) based on asymmetric GaInAs/GaInAsP/AlGaAs separate-confinement heterostructure

Asymmetric GaInAs/GaInAsP/AlGaAs heterostructures with the emission wavelength of 940 and 980 nm were grown by MOCVD. The composition of solid solution in the waveguide layer, Ga_0.74In_0.26As_0.47P_0.53, was chosen based on the calculations of the escape energy of electrons from the quantum well of the active region into the waveguide. Semiconductor lasers with the emission aperture of 100 μm were fabricated from these heterostructures. The CW output optical power of 12 W was achieved at room temperature. The internal optical loss was 0.6 and 0.3 cm^?1 for 940 and 980 nm wavelengths, respectively.     

Cabled-fibre, 1.6Gbit/s, 1550nm transmission experiment

We report on a 1.6Gbit/s transmission experiment through 82.5 km of production-type low-loss pure-silica-core cable (stranded and ribbon) with 43 rotary splices and 2 biconic connectors. A packaged 1.55?m distributed feedback (DFB) laser was the light source. A bit error rate of 2 × 10?10 was achieved using manufacturable transmitters and receivers with no observable error floor.     

Broad range (34nm) quasi-continuous wavelength tuning insuper-structure-grating DBR lasers

The authors present super-structure-grating distributed Bragg reflector lasers that provide a quasi-continuous wavelength tuning of 34 nm with stable singlemode oscillation     

掺饵光纤放大器用1480 nm/1550 nm波分复用器的优化设计

以组合波导理论为基础，分析了1480/1550 nm波分复用器的耦合区横截面形状和尺寸与偏振灵敏度的关系。着重比较了矩形截面和椭圆形截面二种波分复用器的偏振性能，并发现当椭圆截面的短轴与长轴之比为1:1.88时，器件性能几乎与偏振无关。研制成功的1480/1550 nm波分复用器的波长隔离度大于20 dB,偏振灵敏度小于0.1 dB,附加损耗小于0.5 dB。     

A 980-nm band laser diode pump source with a detuned wavelength of1000 nm for praseodymium-doped fiber amplifiers

By using practical high-power 980-nm band laser diodes, efficient direct pumping for a praseodymium-doped fiber amplifier (PDFA) is achieved. The lasing wavelength is detuned from 980 to 1000 nm by selective optical feedback from a fiber grating     

High Efficiency Al-Free 980nm InGaAs/InGaAsP/InGaP Strained Quantum Well Lasers

980nm InGaAs/GaAs/AlGaAs strained quantum well lasers have attracted considerable attentionas pumping sources for the Erbium-doped fiber amplifiers(EDFA) and solid-state lasers[1,2].However,for InGaAs/GaAs/AlGaAs strained quantum well lasers,there liabilityist...