Optical pumping of CO by a convective flow CO laser

A convectively cooled CO laser has been used to optically pump the vibrational distribution of CO preheated in a dc discharge. For maximum pump flux levels of 8 kW/cm², it was found that optical coupling to flowing CO could be achieved only in the presence of discharge preheating and the extent of optical pumping was a strong function of pump wavelength over the range5.0-5.1 mum. The excited CO vibrational distribution was derived by spectroscopic analysis to be similar to the highly nonequilibrium distributions obtained in prior work. Numerical calculations of the vibrational distributions have been performed and reasonable agreement with the experimental results was found.     

Spectral beam combining of a single-mode 980-nm laser array for pumping of erbium-doped fiber amplifiers

With a view to improve the power level and brightness of semiconductor pump lasers, we have resorted to a scalable implementation and achieved spectral beam combining through a low-quality-factor external cavity. For that purpose, a high-power single-mode laser array emitting up to 2.1 W at 3.2 A at 980 nm has been realized, which delivers 1.5 W in external cavity. A power of 0.66 W was finally coupled into the single-mode fiber, with a coupling efficiency of 44%. Pumping experiments of an erbium-doped fiber amplifier utilizing this laser have demonstrated efficiency and noise characteristics similar to what is usually obtained with conventional sources, with the noteworthy advantage of a lower gain excursion over the C-band.     

Narrow-band CO2-TEA laser for efficient FIR laser pumping

To reduce the linewidth mismatch between the emission lines of a CO2-TEA laser and the absorption lines of a low-pressure FIR gain medium a tiltable Ge etalon has been introduced into the TEA resonator. The resulting spectral compression and tunability increase the energy conversion efficiency in a TEA laser pumped CH3OH laser by as much as a factor of 37 and has led to the observation of 14 new FIR laser lines.     

用腐蚀熔融法制造单模激光二极管与单模光纤相耦合的半球微透镜

近年来由于单模光纤研究的极大成功，促进了单模光纤通信系统和单模光纤应用技术的迅速发展。单模光纤的实际损耗已降到接近理论值，因此为进一步改善单模光纤传输系统的信噪比，提高激     

Stable single-mode erbium fiber-grating laser for digitalcommunication

In this paper we report the fabrication of a short, robust, single-mode Er³⁺ fiber-grating laser. This laser is proven by the successful outcome of a long-term bit-error-rate test at the 10^-15 level in a 5- G/s fiber transmission experiment. In the process we present a new pumping geometry, the elucidation of one origin of relaxation oscillations that have plagued previous lasers and the demonstration of a simple electronic feedback scheme for suppressing them. This prototype source shows real promise for use in a high-speed communications system     

Injection locked single mode operation of a tea CO2 laser with high energy extraction

Generation of reproducible smooth pulses from longitudinal mode control of a TEA CO₂ laser by signal injection from a cw CO₂ laser is reported and the operating conditions investigated for several new geometries. Applied to unstable resonators, the efficient and spectrally pure, high power output obtains has important application in the area of optical pumping.     

医用波导CO2激光器

本文报导一种符合医用要求的新型玻璃波导CO2激光器。该器件采用大孔径玻璃波导（d=3～4mm）。提出近场非匹配凹面镜选模的新方法和整体冷却管体的新结构。激光器全长310mm时，能得到输出功率8W左右的稳定基模。连续工作寿命大于1000小时。     

Experimental and theoretical study of noncooled CO laser with short pulse pumping

This paper describes experiments and theory relating to CO laser action in various CO mixtures with N2and/or He. Short-pulse electron beam excitation of1-2 mus produced laser output between 1600 and 1900 cm^-1; the most intense line was at 1788.4 cm^-1and the shortest pulses of 4 μs duration were generated in the CO:He mixture. Although the calculated maximum efficiency was 7 percent, the maximum measured efficiency was 3 percent.     

GaInAsP semiconductor laser amplifiers for single-mode fiber communications

Gain, polarization sensitivity, saturation power, and noise characteristics of quaternary semiconductor laser amplifiers of the Fabry-Perot (FP) and traveling-wave (TW) types are reviewed. The status of antireflection coatings for TW amplifiers is presented. New results concerning the polarization sensitivity and output saturation power of a 1.5-μm buried-heterostructure (BH) amplifier are reported. A theoretical model is presented concerning the influence of the waveguide structure on the maximum internal gain of a CW-operating 1.5- μm BH amplifier, including thermal effects, and a comparison of this model with recent experimental results is reported. The influence of nonresonant losses on the noise factor of 1.5-μm amplifiers is discussed.     

Simple RF-excited CO2 laser

In the letter we describe the construction of a simple RF-excited low-power carbon dioxide laser built with ordinary materials. We achieved an output of 0.5 to 1 W and an efficiency of 5%.     

An improved single-mode Y-branch design for cascaded 1:2 splitters

The power splitting ratio of Y-branches based on step index waveguides has been calculated using three-dimensional (3-D) finite-difference beam propagation method (FD-BPM). Due to interference of the guided mode with quasiguided modes generated at distortions of the waveguide the splitting ratio depends on the wavelength and design parameters of the Y-branch. The simulations show how variations of the splitting ratio can be minimized using a mode-filter in the input section without significant increase of losses or component size     

An injection-locked unstable resonator rare-gas halide discharge laser of narrow linewidth and high spatial quality

An oscillator-amplifier KrF discharge laser system capable of providing up to 400 mJ output with 0.1-cm^-1linewidth in a 20-ns pulse is described. The output beam divergence is described and shown to be affected by the discharge current. The output beam is near the diffraction limit in the direction parallel to the discharge and about three times the diffraction limit transverse to the discharge. Operation with XeCl at up to 250 mJ with similar linewidth and spatial quality is also described.     

Fir laser emissions from population inversion transition by TEA-CO2 laser pumping

In this paper, the numerical analysis is given which is applicable for a TEA-CO₂ laser pumping in search of effective pumping method. The analysis also can estimate the optimum pressure for a given molecule and a given pulse laser. Also we report in this work many FIR laser emissions from population inversion transition which have never observed before using a TEA-CO₂ laser.     

工具钢CO2激光熔凝和相变硬化的研究现状

综述了CO2激光熔凝和相变硬化的国内外研究现状，就目前该领域中存在的问题及其发展方向提出了自己的看法。     

On single-mode injection laser structures for reduced output fluctuations

This paper explores the possibilities of two principles for reducing the fluctuations in power output of the main mode of an injection laser: 1) including within the laser cavity a section of larger bandgap than the energy of the photons generated; and 2) use of very small wavelength-selective loss differences between the main mode and the side modes. Transient response and steady-state fluctuations are calculated from a rate-equation model. New approximate analytical expressions are given to make possible the calculation of 1) the critical gain-loss term and 2) the consequent laser characteristics. It is shown that a very small side-mode loss difference increases the coupling between the carrier density and the main-mode photons. This produces very fast transient response. It is also shown that the larger bandgap region smoothens the output power and enhances the main-mode power at constant driving current. These results give promise of a low-power-level laser capable of multigigabit direct modulation     

适用于动目标激光测距系统的GICC TEA CO2激光器

（一）引言 TEA CO2激光器在脉冲放电过程中由于工作气体的分解而产生O2。它们的存在使放电中的负离子密度大大增加，从而引起放电的不稳定性。在通常的封离式器件中，放电空间中的这种生成物是靠扩散弛豫的。对于放电区宽度为厘米量级的激光器，从放电区扩散出去的时间为另点几秒到几秽。因此，激光器只能在1～2次／秒的低脉冲重复频率（PRF）下工作。     

激光汽化兼热杀癌肿瘤理论模型的研究与定量计算

本文研究了光纤插入法汽化兼热杀癌肿瘤的激光治癌模型及定量计算方法，并给出了临床上三种常见热效应激光的数据计算结果，根据汽化兼热杀的特点把激光在生物组织中的热传导分为三个子过程，并建立了相应的定量模型，从理论上证明需分两段时间调节激光功率密度，以控制或选择光纤端面汽化区域的大小，给出选择安全有效的激光功率密度，照射时间和热杀癌边界等理论方法，尝试解决如何在激光治癌中心汽化后可能发生癌细胞溅射或扩射或     

Injection seeding for single-mode operation in an optically pumped high-power D2O laser

Spectrally narrow, pulsed outputs consisting of almost a single mode have been obtained from an optically-pumped high-power (200kW) D₂O laser by adopting the injection seeding method, where single-mode radiation (seed pulse) from a low-power, compact D₂O laser has been injected into the main D₂O laser. Spectrally narrow outputs with high power having spectral widths as narrow as 5 MHz have been obtained, when the seed pulses with frequency tuned to one longitudinal mode of the main D₂O laser have been injected at a time sufficiently before the lasing of the main laser took place. The experimental results have been compared with those of numerical simulation modified to include the injection field with varying injection times.     

Improved acousto-optic modulators for CO2 heterodyne laser systems

Acoustic damping layers of indium on germanium acousto-optic modulators are found to reduce unwanted acoustically delayed modulations of transmitted CO2 laser beams by, typically, 10 dB for the first reflected pulse, the second reflected pulse becomes barely observable; subsequent reflections become unobservably small. A more sensitive monostatic laser radar is therefore obtainable.