外腔半导体激光器的单纵模机制

本文建立了一种外腔半导体激光器单纵模机制的模相互作用模型。由于引入四波混频耦合项,模相互作用的效应对次级模的影响是对称的,均使次级模受到增益抑制。     

一种内反射耦合的单纵模半导体激光器模型

提出了一种内反射耦合的单纵模半导体激光器模型。利用谐振放大器的原理计算了光谱特性。计算表明:如果选用适当腔长的激光器耦合,可以得到单纵模输出。     

YAG laser operation by semiconductor laser pumping

Yttrium aluminum garnet (YAG) laser operation has been achieved using a single gallium arsenide laser diode as the pump. Repetition rates of 200 pulses per second have been achieved in initial experiments. Compared to flashlamp pumping, semiconductor laser pumping requires less. than 5 percent of the light energy to accomplish YAG lasing. Extraordinary repeatability of laser output, pulse to pulse, has been obtained.     

Single longitudinal mode operation of a transversely excited CO2laser

High peak-power output has been obtained from a transversely excited CO2laser in a single longitudinal and lowest order transverse mode. An intracavity etalon was used for mode selection in a laser system designed to operate effectively at reduced pressures.     

Single longitudinal mode control of semiconductor lasers by rectangular conical diffractor system for wavelength-division-multiplexing transmission

A new external feedback system named the rectangular conical diffractor (RCD), which is composed of a diffraction grating and a mirror, is designed. This system has advantages for wavelength-division-multiplexing transmission systems. By using this system in both single and multimode semiconductor lasers: 1) the oscillation wavelength of a semiconductor laser can be selected freely; 2) some semiconductor lasers oscillate at different wavelengths from one another simultaneously, and no interference exists between the oscillation wavelengths under the condition that each semiconductor laser is operated independently; and 3) the selected wavelength is stable against temperature variation of the lasers.     

Single longitudinal mode operation of a CO2TEA laser by injection locking with a tunable CO2waveguide laser

A CO2TEA laser was frequency tuned by means of injection locking with a tunable waveguide laser as master oscillator, using a special injection method. Injection-locking experiments were performed at different operating conditions and varying parameters such as laser lines, master oscillator power, and frequency offset from the line center.     

CuBr激光器的自锁模的极限和单纵模运转

本文报道了在小尺寸的CuBr激光器中,采用三镜复合腔的模式淬灭效应,通过调整复合腔的结构参数,使CuBr激光的纵模间隔在660MHz的范围内实现可调,从而在实验上清晰地观察到CuBr激光自锁模的极限。同时,在复合腔CuBr激光器中,首次实现了激光的单纵模运转。     

An efficient electron-beam-pumped semiconductor laser for the green spectral range based on II–VI multilayer nanostructures

Emission characteristics of an electron-beam-pumped Cd(Zn)Se/ZnMgSSe semiconductor laser are studied. The laser’s active region consists of a set of ten equidistant ZnSe quantum wells containing fractional-monolayer CdSe quantum-dot inserts and a waveguide formed by a short-period superlattice with the net thickness of ～0.65 μm. Lasing occurs at room temperature at a wavelength of 542 nm. Pulsed power as high as 12 W per cavity face and an unprecedentedly high efficiency of ～8.5% are attained for the electron-beam energy of 23 keV.     

Influence of electron energy on the characteristics of electron-beam-pumped semiconductor lasers

The influence of electron energy on the characteristics of electron-beam-pumped GaAs lasers is studied experimentally. Increases in the electron energy lead to increases in output power and decreases in beam divergence. Above radiation-damage threshold, a degradation of the laser output with time is observed due to bulk defects created by the beam. These defects are partially self-annealing if radiation is stopped.     

Transverse and longitudinal mode control in semiconductor injection lasers

Mechanisms which determine the oscillating transverse and longitudinal modes in semiconductor injection lasers are discussed in this paper. The analysis is based on the semiclassical method in which the optical field is represented by Maxwell equations and the lasing phenomenon is analyzed quantum mechanically using the density matrix formalism. Guided modes are classified by the relation between refractive index and gain-loss differences at the boundaries of the active region as normal guided mode (index guiding), active-guided mode (gain guiding), and leaky mode (anti-index guiding). The guiding loss and cutoff conditions are given for these modes. The optimum range to obtain stable fundamental transverse mode operation is discussed with respect to several guiding factors, such as width of active region, the refractive index difference, and gain-loss differences at the boundaries of the active region. Longitudinal mode behavior is discussed in terms of electron transition mechanism in semiconductor crystals. The relaxation effect of the electron wave is introduced in this model. Profiles of the saturated gain and the spatial diffusion of the electron are related to this relaxation effect. Mode competition phenomena are analyzed, and a strong gain suppression among the longitudinal modes is shown to be as an intrinsic property of semiconductor lasers. The possibility of obtaining single longitudinal mode operation is postulated. Physical influences for stable single longitudinal mode operation are discussed in terms of transverse mode control (or stripe structure), spontaneous emission, threshold current level, impurity concentration in the active region, and direct modulation. Some experimental results are also given to support these analyses.     

Lateral and longitudinal mode discrimination in index-guidedcircular ring semiconductor lasers

We present the first analysis of the mode structure and thresholds of index-guided ring lasers, and on longitudinal mode discrimination of X-junction-coupled ring lasers. Submilliampere thresholds can be achieved with single-lateral-mode ring lasers having small refractive index steps. In addition, strong longitudinal mode discrimination can be obtained with ring lasers of different cavity lengths coupled via an X junction     

半导体激光器的自脉动与被动锁模

利用普适GaAlA3双异质结半导体激光器，观察到被动锁模现象。讨论了半导体激光二极管的自脉动、外腔中的诱导自脉动以及被动锁模间的区别与联系。     

锑化物中红外单模半导体激光器研究进展

锑化物材料因为其天然的禁带宽度较小的优势,是2~4 m波段半导体光电材料和器件研究的理想体系。近年来,国内外在锑化物大功率半导体激光器方面的研究取得了很大的进展,实现了大功率单管、阵列激光器的室温工作。然而,由于锑化物材料与常见的半导体单模激光器制备工艺的不兼容性,只有少数几个研究单位和公司掌握了锑化物单模激光器的制备技术。文中介绍了锑化物单模激光器常用的侧向耦合分布反馈激光器的基本原理,分析了其设计的关键技术,回顾了锑化物单模激光器的设计方案和制备技术,并针对国内外锑化物单模激光器主要研究内容进行了总结。     

外腔半导体激光器单频输出的长期稳定

一、引言 由于光纤通讯、光纤传感、检测二光谱分析、频标、光陀螺等领域的需要；单频半导体激光器的研究近年来受到广泛重视并得到迅速发展，由于采用了长外腔选模技术，已实现了线宽小于100 kHz的单频输出~[1-3]。而频率长期稳定工作则刚刚开始~[4]。通常认为，造成半导体激光器输出频率漂移及跳模的原因是管芯温度和注入电流的波动，因此稳频工作     

Theoretical analysis of longitudinal mode coupling in external cavity semiconductor lasers

The single longitudinal mode behavior in long external cavity semiconductor lasers is discussed. Experimentally, the laser exhibits a single frequency oscillation even for an external cavity length of 100 cm. The mode selectivity of a composite cavity is shown to be insufficient to explain the experiments. Longitudinal mode coupling in semiconductor lasers is found to arise from an interference effect between the modes on the interband transition probability of electrons. Mode coupling equations are derived, which indicates that the single mode oscillation in long external cavity semiconductor lasers is brought about when the coupling strength goes beyond a critical value. It is shown that the effect of the hole burning in the external cavity semiconductor lasers is similar to that in the solitary laser.     

Transition from the lowest linewidth mode operation to coherencecollapse in a semiconductor laser with feedback from a distant reflector

The influences of optical feedback from a distant reflector on single-mode semiconductor laser operation are analyzed theoretically. The stable operation in the lowest linewidth mode and the feedback parameter for the onset of coherence collapse are systematically derived. In the feedback regime for the lowest linewidth mode operation, the laser principally operates at the emission frequency of the solitary laser at the beginning of the operation with the feedback. It is shown exactly by asymptotic analysis of the equation for the field phase in the semiconductor cavity considering the time-lag of the feedback that the laser comes to operate in the lowest linewidth mode. In the lowest linewidth mode operation, the laser is stably phase-locked to the feedback. In the semiconductor cavity, the field amplitude and the field phase oscillate in almost the same phase in the fluctuation modes related to the relaxation oscillations, In the lowest linewidth mode operation, the phase oscillations enhance the amplitude oscillations through the feedback-action's dependence upon the phase difference between the field in the semiconductor cavity and the feedback. Thus, the damping of the relaxation oscillations decreases with further increased feedback and the transition to the coherence collapse occurs     

561 nm全固态单纵模激光器

报道了一台激光二极管端面泵浦的全固态、单纵模561 nm黄光激光器。采用镀制窄带反射膜的方法来抑制增益较大波长的起振,并通过I类临界相位匹配LBO晶体腔内对1123 nm 基频光倍频及V型腔结构,选择单一波长运转,进一步通过F-P标准具选频方法,获得 561 nm 单纵模激光的稳定输出。在泵浦功率为2.4 W时,获得了80 mW的561 nm单纵模激光,光-光转换效率为3.3%,纵模线宽为24.1 MHz。该激光器在人眼黄斑病变治疗仪及流式细胞仪等生物医学领域,具有很高的实用价值,是近年全固态激光器的研究热点之一。     

Time duration of output pulse in electron-beam-pumped CdS laser

Time duration of the output pulse of electron-beam-pumped CdS laser was investigated. It increased with increase of the excitation current density and was of the order of 100 ns at the beam voltage of 25 kV. It was shown experimentally that the quenching of the laser oscillation is due to the rise of the threshold current density as the result of the temperature rise in the active region of the crystal. The expression for the duration of laser oscillation based on this model was derived and compared with the experimental results. The dependence of the duration on the excitation current density was explained by this model.     

Theoretical and experimental investigation of amplified spontaneous emission in electron-beam-pumped semiconductor lasers

Linear and nonlinear theories of amplified spontaneous emission in longitudinally-pumped semiconductor lasers have been developed. Spatial inhomogeneity in three dimensions and spectral inhomogeneity of gain and spontaneous emission are taken into account. Experiments to investigate the dependency of lasing threshold and differential efficiency of electron-beam-pumped semiconductor lasers on excited region diameter have been performed. The results of threshold measurements have agreed well with the linear theory calculations, while accounting for the results of differential efficiency measurements has required the development of a nonlinear theory. The data for non-linear calculations were provided by experiments on saturation of spontaneous emission. The results of experiments have definitely proved the inhomogeneity of gain. Based on the data obtained from experiments, the nonlinear calculations have explained the dependence of differential efficiency on the excited region diameter.