半导体激光器稳频技术

窄线宽稳频激光器在精密干涉测量、光学频率标准、激光通信、激光陀螺、激光雷达、基本物理常数测量和冷原子系统等研究领域有着广泛的应用。自由运转的半导体激光器每天的频率漂移量可以达到GHz,因此研究半导体激光器的稳频具有十分重要的意义。以780 nm的半导体激光器稳频为例,介绍了目前广泛使用的各种半导体激光稳频技术的基本原理及试验方案,如消多普勒饱和吸收光谱稳频技术、消多普勒双色谱稳频技术、调制转移谱稳频技术、调频光谱稳频技术和频率-电压转换稳频技术,并对各种稳频方法的性能和特点进行了分析。     

半导体激光器稳频技术研究

具有窄线宽和较高频率稳定性的半导体激光器,在高分辨率激光光谱、原子频率标准、大气和环境监测、光通信等众多领域中具有极其重要的应用。因此半导体激光器的稳频研究具有十分重要的意义和应用价值。较为全面的总结了目前国内外广泛应用的各种半导体激光器稳频技术,简要介绍了各稳频技术的实验方案及基本原理;对各方案的特点、能够达到的频率稳定水平、优缺点等进行了全面的分析。对半导体激光器稳频发展趋势做了预测。     

单量子阱半导体激光器在输出反馈损耗调制方式下的双稳特性

利用速率方程求出了输出反馈损耗调制型双稳半导体激光器输出光强稳态解的解析表达式。利用双区共腔ＧａＡｓ／ＡｌＧａＡｓ单量子阱半导体激光器，观测到半导体激光器在输出反馈损耗调制方式下的光双稳特性。比较速率方程解的理论计算曲线和实验观测到的双稳特性曲线后发现，两种双稳特性曲线随反馈损耗调制系数等器件参量变化的规律完全一致。     

与光探测器单片集成双稳半导体激光器的特性

利用光输出反馈泵浦方式,首次观测到PD/LD单片集成型光学双稳态。电路简单、稳定性好;双稳范围的宽度可根据需要在很大范围内调节。利用半导体激光器的速率方程理论计算了这类双稳激光器的稳态行为,发现实验结果和理论计算符合的很好。     

铷吸收半导体激光稳频光波长标准研究

文中介绍了用铷吸收光谱法对半导体激光器进行稳频,从而稳定其输出波长;通过对包括半导体激光驱动源、稳频器、吸收室、光路等系统的优化设计,达到具有高信噪比微分误差信号,从而大大提高了半导体激光器稳频锁定灵敏度和长期稳定性。采用文中介绍的方法建立的光波长标准系统,其波长的测量重复性、稳定性可满足当前和将来很长一段时间光波长计校准的需要。     

半导体激光器光电混合双稳装置的双稳特性与器件参量之间的关系

报导了输出反馈泵浦型双稳半导体激光器双稳物性随器件参量变化的实验结果，双稳实验曲线和理论计算曲线的对比分析表明，双稳特性随各参量变化规律安全相同，实验和理论之间的微小差别来源于光探测器的实测饱和曲线和理论模型之间的差异，以及实际的半导体激光器存在自发辐射。     

研究双稳半导体激光器的新方法──逐点跟踪法＊

逐点计算非均匀泵浦半导体激光器输出双稳环上四个关键点处的运行参量,对吸收型双稳半导体激光器进行了研究。该法不但可以给出双稳激光器“启动”和“下跳“点的阈值电流和相应的输出功率,而且还可以给出用这些值来表示的增益截面的解析表达式,这将使得实验上可以简单地由测量到的双稳环的宽度和高度来确定难于测定的增益截面。     

半导体激光器的原子法拉第反常色散光学滤波器光反馈稳频

为提高半导体激光器的频率稳定性，利用原子法拉第反常色散光学滤波器（FADOF）超窄带的选频透射特性，将其置于半导体激光器的外腔中作选频元件，采用光反馈的方法，使得透射率低的激光频率分量被抑制，透射率高的激光频率分量被加强，有效地实现了光反馈激光稳频。利用Cs原子法拉第反常色散光学滤波器工作于D2线852nm的4峰窄带透射状态。通过调节半导体激光器的温度和电流，调谐半导体激光器的输出波长，将激光器锁定在任何一个透射峰上，用26％的光反馈量，使稳频后的激光频率长期稳定性保持在75MHz／2h以内，而且采用这种稳频方法的输出激光中心波长一直稳定在频率基准上，没有单方向漂移。同时，还实现了Cs原子法拉第反常色散光学滤波器稳频半导体激光器结构的一体化，使其具有实用性。     

吸收型双稳半导体激光器

对两段式吸收型双稳半导体激光器的速率方程组进行了解析求解,并逐点跟踪定义双稳环的关键点,确立了介质发射截面与双稳环宽度和高度的关系式。     

外腔半导体激光器输出双稳环形状分析

研究了因折射率与载流子相互关联而引起的外腔半导体激光器的双稳特性，分析了不同条件下各种不同形状的载流子密度双稳环，计算了相应情况下的功率双稳环。     

Operation of an all-optical bistable device dependent upon incidentand transmitted optical power

The authors describe the optically bistable operation of an all-optical nonlinear Fabry-Perot etalon (NLFP) in which the power-dependent cavity phase shift has a contribution dependent on the power incident on the cavity. When the contributions have the same parity, the optically-bistable behavior is essentially the same as that seen in the now standard bistable NLFP (counterclockwise hysteresis in transmission). For opposite parity there is a range of relative strengths for which bistable operation cannot be obtained, but, outside of that range, bistable behavior having clockwise hysteresis in transmission is possible. This latter bistable behavior is demonstrated, with the NLFP being a GaAlAs laser diode amplifier driven by a similar diode laser. Low-frequency modulation of the laser power by direct variation of the laser drive current produced a small shift in laser wavelength proportional to the laser power, providing the cavity phase shift term proportional to the incident power, while the nonlinear refractive index of the NLFP provided the phase shift proportional to the transmitted power     

19 ps switching of a bistable laser diode with 30 fJ optical pulses

19-ps optical switch-on of a bistable laser diode with only 30-fJ input coupled optical energy at a repetition rate of 500 MHz is reported. The bistable laser was an inhomogeneously pumped three-section Fabry-Periot laser diode. The switch-off time was 94 ps, probably limited by the duration of the electrical reset pulse. Longer turn-on delay times were recorded when switching with less input energy     

InGaAsP/InP CCTS双稳态激光器的纵模及偏振特性

本文给出了InGaAsP/InP CCTS双稳态激光器的模式特性。通过实验得到对双稳态激光器来说其吸收区的存在,使其对偏振及纵模的选择有一定的作用,使得TM模的输出强度在总输出中占的比例更小,及在双稳区内给出单纵模输出。     

The effect of electronic feedback on semiconductor lasers

Negative electronic feedback (EFB) has a strong effect on the performance of a bistable laser diode amplifier and on injection-locked lasers. Negative EFB drastically reduces the switching-up input power level and the hysteresis in the input-output power characteristic and in the tuning curves of the bistable laser amplifier. Furthermore, negative EFB leads to a reduction in the time delay associated with optical switching in diode laser amplifiers. This provides a means of enhancing the versatility of the proposed system in some potential applications. For an injected-locked laser, negative EFB achieves a broadening in the locking bandwidth and its dynamically stable region     

Large optical bistability and self pulsations in three section DBRlaser diode

A bistable operation with a hysteresis of 24 mA in the power-current curve of a three section DBR laser is reported. The laser threshold at increasing current is 51 mA while in the opposite direction the laser action is sustained down to 27 mA. The same effect was observed by monitoring the laser threshold through the Bragg and phase section currents. In a large part of the current range which corresponds to the bistable laser operation, strong self pulsations have been observed at frequencies between 1.5 GHz and 3.5 GHz with an amplitude of up to 31.4 dB     

Optical spectral bistability in a semiconductor fiber ring laserthrough gain saturation in an SOA

We demonstrate the operation of optical bistability in a widely tunable semiconductor fiber ring laser, using a semiconductor optical amplifier (SOA). The laser can be operated in two bistable states: the spectrum of the first state has one main lasing peak with very narrow linewidth, and the second state has simultaneous oscillation of two main peaks at different wavelengths. The two bistable states can be switched to each other using either electrical or optical methods. We further explain the bistable operation using the theory of two-mode competition through gain saturation in the SOA     

All-optical bistable switching dynamics in 1.55-μm two-segmentstrained multiquantum-well distributed-feedback lasers

All-optical bistable switching dynamics of 1.55-μm two-segment strained multiquantum-well (MQW) distributed-feedback (DFB) lasers were systematically studied both experimentally and theoretically. Some fundamental optical functionalities, including all-optical set-reset (flip-flop) operations, were demonstrated. The switching responses of these bistable lasers were studied, for the first time, with optical injection from a single-mode DFB laser, indicating that the switching dynamics based on gain quenching and absorption saturation are inherently different. A theoretical model including optical injection was developed to study these all-optical bistable switching characteristics in segmented bistable lasers. It was found that the nonuniform distribution of the photon density in the bistable laser cavity induced by optical injection was essential to perform the time-domain switching operations. Simulations showed a good agreement with experimental observations and indicated design improvements. Although the switching responses in the range of tens of picoseconds can be obtained with these bistable lasers, the maximum repetition frequency of the bistable systems would still be limited to the hundreds of megahertz due to the slow carrier recovery time (5 ns) of the lasers     

Magnetically programmable bistable laser diode with ferromagneticlayer

A new design of bistable laser diode, which consists of a gain section, absorption section, and nonreciprocal section, is proposed. The nonreciprocal section is made of a semiconductor optical amplifier covered by a ferromagnetic layer. The nonreciprocity of magneto-optical effect significantly modifies a photon density distribution in the laser cavity and enlarges a width of hysteresis loop of bistable laser diode. The bistability can be switched on or off by reversing magnetization of the ferromagnetic layer