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相干光时域反射仪中受激布里渊散射的抑制 总被引:1,自引:1,他引:0
采用对分布反馈半导体激光器(DFB-LD)直接进行小信号电流调制的方法抑制相干光时域反射仪(COT-DR)中的受激布里渊散射(SBS),分析了DFB-LD受到小信号电流调制时的频谱特性以及SBS阈值和频谱宽度的关系,设计了实验电路和光路抑制光纤中SBS。理论分析和实验结果表明,在低频调制电流处,光源频谱宽度随调制频率增加而减小,随调制幅度增加而增加,而SBS随频谱宽度增加而减弱,直接用电流调制激光器可抑制COTDR中的SBS。 相似文献
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近年来,全固态激光器快速发展,将取代灯抽运固体激光器成为激光器件领域的主流.在激光加工和激光显示等领域的应用中,常常需要对光进行调制.直接调制抽运LD的电流实现全固态激光器的调制将是一个重要的发展方向.
本文基于激光显示应用的需要,首次对全固态红外光和绿光激光器的低频(100 Hz~20 kHz)和大电流(-2 A)调制特性进行了实验研究.测量了激光输出功率、接通延迟时间、阈值电流、正脉冲的占空比等与调制频率和调制电流的关系,对808 nm 抽运光、1064 nm基频光和 532 nm倍频光的调制特性进行了比较和讨论.(OC26) 相似文献
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(上接第14期) 光发射机的任务是把从前端送来的高频电视信号变成光信号,使其能在光导纤维中传输.光发射机按照调制方式划分为调频、调幅和数字调制等多种.目前用得最多的是多路调幅光发射机,在调幅光发射机中按照强度调制的方式不同又分为直接调制光发射机和外调制光发射机.直接调制光发射机是利用高频电视信号(将信号电流叠加到激光器的偏置电流上)来控制半导体激光器的偏流,进而控制激光器的输出光强.外调制光发射机是在激光器输出激光之后,让其通过一个外调制器,使激光的强度随多路调幅信号电压而改变.无论哪种形式的光发射机都具有射频激励单元电路,此功能电路的好坏直接决定着光发射机指标的优劣.鉴于目前市场上直接调制光发射机占大多数,此处RF驱动电路的介绍偏重于直接调制光发射机. 相似文献
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第三章光发射机的射频激励功能电路
光发射机的任务是把从前端送来的高频电视信号变成光信号,使其能在光导纤维中传输.光发射机按照调制方式来划分有调频、调幅和数字调制等多种.目前用得最多的是多路调幅光发射机,在调幅光发射机中按照强度调制的方式不同又分为直接调制光发射机和外调制光发射机.直接调制光发射机是利用高频电视信号(将信号电流叠加到激光器的偏置电流上)来控制半导体激光器的偏流,进而控制激光器的输出光强;外调制光发射机是在激光器输出激光之后,让其通过一个外调制器,使激光的强度随多路调幅信号电压而改变.无论哪种形式的光发射机都具有射频激励单元电路,在光发射机中,射频激励功能电路是最重要的单元电路.此功能电路的好坏直接决定着光发射机的指标的优劣.鉴于目前市场上直接调制光发射机占大多数,此处RF驱动电路的介绍偏重于直接强度调制光发射机. 相似文献
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引言红外探测器的响应速度是系统设计中的一个头等重要的参数。响应速度通常用频率响应曲线表示,或用系统对一个光脉冲的响应表示。在低频时,是使用调制信号源来得到频率响应曲线。当频率接近兆赫级时,必须采用其他方法来获得频率响应曲线。在注入式激光器工作的光谱区,可对这类激光器进行电流调制而取得高频调幅光。已采用的其他方法是利用连续波激光器在荧光线宽范围 相似文献
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808nm量子阱激光器电流调制特性的实验研究 总被引:3,自引:0,他引:3
本文首次对高功率GaAs/GaAIAs量子阱激光器(808nm)的低频(100Hz-20KHz)电流调制特性进行了实验研究。结果表明:激光发射的接通延迟时间、阈值电流、正脉冲的占空比、平均功率、峰值功率随调制频率和电流而变化。 相似文献
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本文介绍了利用光谱分析测量DFB LD调制特性的方法及装置。介绍了测量装置光路部分和电路部分的技术要点。对DFB LD的实测说明:注入DFB LD电流的变化不会引起注入载流子密度明显变化,进而不会由此引起光频率的变化。这种测量方法可方便而准确地测量使用DFB LD的光端机的直接光强调制深度。 相似文献
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Transmission characteristics of a CPFSK differential detection system with LD direct modulation are studied by computer simulation. Simulation results show that the optimum wavelength for LD direct modulation CPFSK transmission shifts to a wavelength longer than zero dispersion wavelength because of the phase difference between the intensity and frequency modulation components. A precise investigation of the dependence of optimum total dispersion on several parameters reveals the essential role of the phase difference between intensity and frequency modulation induced by LD direct modulation. The transmission distance allowing a 1-dB power penalty at 10 Gb/s is 117 km for a wavelength 30 nm shorter than the zero dispersion wavelength, while the distance is 183 km for a wavelength 30 nm longer. This indicates that the zero dispersion wavelength shift is 11 nm for 100-km transmission 相似文献
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本文讨论了半导体激光器(LD)的直接调频(FM)特性,指出随着偏置电流的增大,FM响应降低,伪强度调制(IM)响应增大,并给出了一种新的描述FM能力的方法. 相似文献
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Wavelength shift during the period of direct modulation (dynamic wavelength shift) for injection lasers having a BH structure has been investigated both experimentally and theoretically. A GaInAsP/InP BH laser emitting a nominal wavelength of 1.61 μm was modulated by a sinusoidal current at frequencies in the range of 0.2-2 GHz. The full width of the dynamic wavelength shift was 0.35 nm at a modulation frequency of 1.8 GHz, and a modulation depth of 63 percent at a bias current 1.14 times the threshold current. It was found that the width of the dynamic wavelength shift increases with proportion to the modulation depth, and with inverse proportion to the bias current at a frequency below 1 GHZ. The differential coefficientdn/dN of refractive indexn for carrier densityN in the active region was measured for the purpose of the analysis. The value obtained is-1.2 times 10^{-20} cm3. The dynamic shift of the lasing wavelength was found to be characteristic of the change of the refractive index induced by the oscillation of carrier density in the active region during intensity modulation. The theoretical shift shows maximum value at a resonance-like modulation frequency. The peak height of the resonance wavelength shift is strongly affected by carrier diffusion in the transverse direction, and has a minimum value when stripe width is nearly equal to carrier diffusion length. 相似文献
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Fujita T. Ishizuka S. Fujito K. Serizawa H. Sato H. 《Quantum Electronics, IEEE Journal of》1984,20(5):492-499
Static and dynamic properties of a GaAlAs laser diode with an external cavity (1.5-50 cm) have been studied experimentally, it is found that the optical feedback induced intensity noise is strikingly suppressed by 30 dB when a single frequency oscillation is realized with good phase matching. The threshold of modulation depth, over which intensity noise increases abruptly, has been measured as a function of the modulation frequency in a range of 10-400 MHz. It has the maximum at about 40-70 MHz and increases with the decrease of the external cavity length. On the basis of the compound cavity model the phase and gain conditions for the single frequency oscillation are discussed and the threshold modulation depth is calculated, which is shown to be in good agreement with the experimental results. 相似文献
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在激光二极管(LD)正弦相位调制(LD-SPM)干涉仪中,通过注入电流调制激光二极管波长的同时,光源输出的光强也被调制,成为测量误差的主要来源之一.提出一种新的消除激光二极管正弦相位调制干涉仪中光强调制影响的干涉仪,给出了具体的理论分析.该干涉仪采用全光纤结构,有效减小外界干扰对干涉测量的影响;采用容易实现的前置信号处理电路和实时相位检测器对干涉信号进行处理,消除了激光二极管光强调制产生的测量误差;同时实现了物体微小位移的高精度实时测量,测量的重复精度达到1 nm.实验结果与其他消除光强调制影响的方法测得的结果基本一致,验证了该方法的实用性. 相似文献
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Measurements of the intensity modulation induced on the optical output of a proton-bombarded stripe-geometry junction laser by sinusoidal modulation of the laser current at 1200 MHz are reported. Emission occurs in short pulses at any bias current if the current modulation is sufficiently Strong, but only at bias currents which place the laser's internal resonance in the vicinity of one half or one times the modulating frequency if the current modulation is weak. The apparent threshold for lasing is shown to decrease when the RF modulation depth reaches 100 percent, but linearity of the current dependence of the average output power is not maintained at high optical power levels. 相似文献