同带抽运高效率光纤放大器

以光纤光栅为谐振腔搭建了波长为1020 nm的光纤激光器,并通过两级级联放大获得了590 mW的最大输出功率. 利用获得的波长为1020 nm的激光进行了波长为1064 nm种子光同带抽运放大,实验研究了不同增益光纤长度时放大器的输出功率和转换效率. 当增益光纤长度为8.5 m时,放大器最大输出功率为385 mW,斜率效率为81%. 进行了波长为976 nm的半导体激光器直接抽运波长为1064 nm种子光的实验. 在增益光纤长度最优时,其斜率效率为56.4%. 实验结果表明,同带抽运方式比传统抽运方式具有更高的转换效率. 研究结果可为波长为1020 nm的激光高功率放大和波长为1064 nm的光纤激光高功率同带抽运放大提供一定的参考. 关键词： 同带抽运 光纤放大器 斜率效率     

33 W continuous-wave single-frequency green laser by frequency doubling of a single-mode YDFA

A high power continuous-wave single-frequency green fiber laser by second-harmonic generation of a Yb-doped fiber amplifier(YDFA)is developed.A linearly polarized single-mode fiber amplifier produces a 60 W infrared laser at 1064 nm with a 103 W incident diode pump laser at 976 nm,corresponding to an optical conversion efficiency of 58%.An external bow-tie enhancement cavity incorporating a noncritically phase-matched lithium triborate crystal is employed for second-harmonic generation.A 33.2 W laser at 532 nm is obtained with a 45 W incident 1064 nm fundamental laser,corresponding to a conversion efficiency of 74%.     

Wavelength spacing tunable dual-wavelength single-longitudinal-mode fiber ring laser based on fiber Bragg gratings

A wavelength spacing tunable dual-wavelength single-longitudinal-mode fiber ring laser is presented by employing separated fiber Bragg gratings. By using a saturable-absorption-induced grating filter and a hybrid gain medium formed by a semiconductor optical amplifier and an erbium-doped fiber amplifier, stable single-longitudinal-mode lasing is achieved at room temperature. Wavelength spacing of the proposed fiber laser can be tuned in a range from 0.1 to 1.3 nm.     

High-peak-power second-harmonic generation of single-stage Yb-doped fiber amplifiers

A high-peak-power and high-repetition-rate fiber laser architecture is successfully demonstrated using a single-stage fiber amplifier. Nonlinear optical effects in a fiber amplifier degrade the monochromaticity of amplified laser pulses. In general, it is difficult for a non-monochromatic laser pulse to realize high-order harmonic generation with bulk nonlinear optical crystals. To overcome this problem, a single-stage amplifier architecture and a gain fiber with a high cladding absorption coefficient are employed. Furthermore, single-stage amplification enables the use of a multi-longitudinal mode electro-optically (EO) Q-switched micro seed laser. This architecture can generate a peak power of 100 kW at 50 kHz and an average power of 10 W. A second-harmonic conversion efficiency of 51% is obtained using this architecture and a LiB₃O₅ (LBO) crystal.     

32 W百兆赫兹高重频可调谐单频激光光源

通过对连续种子光源的光强调制,并利用光纤放大器和固体介质放大器结合的混合放大方式,实现了百兆赫兹高重频可调谐单频激光光源。系统在基模输出条件下的最大输出功率为31.9 W,光束质量因子小于1.5,脉冲重复频率达到100 MHz,脉宽1 ns,测量得到的光束线宽小于0.8 GHz。实验结果验证了通过对连续光源进行光强调制获得高重频脉冲光源的可行性,并验证了混合放大方式是获得功率放大的一种有效手段。     

All-fiber clad-pumped Tm3+-doped fiber amplifier using high power fiber combiner

The diode laser (LD) clad-pumped 1947.6 nm continuous wave (CW) Tm³⁺-doped fiber amplifier is reported using the master oscillation power amplifier (MOPA) method. The injected seed laser is provided by an all-fiber LD-clad-pumped Tm³⁺-doped single-mode fiber laser, which has a nearly 2.4 W maximal output power and 0.1 nm ultra-narrow linewidth based on the intracore reflection FBG. Using the 25/400 μm double-clad LMA Tm³⁺-doped fiber as the gain fiber, the output maximal output power is 30.6 W from the fiber amplifier, with a slope efficiency of 39.1% respected to the LD total output power. A high power multi-mode fiber combiner is used to couple high power LD light into the gain fiber. The output wavelength is also located at 1947.6 nm, with the slightly expanded laser linewidth of 0.2 nm.     

主振荡功率放大结构窄线宽全光纤激光器334 W高功率输出

 搭建了一台全光纤结构的窄线宽高功率掺镱光纤激光器。种子激光的输出功率大于40 mW,线宽窄于100 MHz。采用主振荡功率放大结构三级放大,主放泵浦功率为405 W时得到了334 W的窄线宽高功率激光输出,光光转换效率为82.4%。目前,激光器输出功率仅受限于泵浦功率,增加有效泵浦功率即有望进一步提高输出功率。     

Dual-core ytterbium fiber amplifier for high-power 1060 nm swept source multichannel optical coherence tomography imaging

A novel (to our knowledge) dual-core ytterbium (Yb(3+)) doped fiber, as an optically pumped amplifier, boosts the output power from a 1060 nm swept source laser beyond 250 mW, while providing a wavelength tuning range of 93 nm, for optical coherence tomography (OCT) imaging. The design of the dual-core Yb-doped fiber amplifier and its multiple wavelength optical pumping scheme to optimize output bandwidth are discussed. Use of the dual-core fiber amplifier showed no appreciable degradation to the coherence length of the seed laser. The signal intensity improvement of this amplifier is demonstrated on a multichannel in vivo OCT imaging system at 1060 nm.     

基于高双折射光纤布拉格光栅的自动增益控制掺铒光纤放大器

掺铒光纤非均匀展宽引起的空间烧孔现象导致单波长激光并不能完全控制放大器增益,提出了一种新颖的自动增益控制掺铒光纤放大器的结构:即采用高双折射光纤布拉格光栅产生抽运光,其写制光栅的波峰对应的波长分别为1549.3 nm和1549.83 nm,波长间隔为0.53 nm。通过调整偏振控制器,就实现了单激光或双激光的增益控制。这种设计增益控制范围为40 nm(1530~1570 nm),当输入功率在-40~-15 dBm的动态范围内,双激光增益控制的掺铒光纤放大器的平均增益和噪声系数分别约为22.22 dB和8.69 dB,而它们的漂移分别被钳制在0.69 dB和1.51 dB。系统性能测试表明:双激光控制掺饵光纤放大器在稳定性方面比单激光有着明显的优势。     

增益竞争双波长放大单频光纤放大器理论研究

引入增益竞争是抑制单频光纤放大器中受激布里渊散射(SBS)的有效方式. 在单频光纤放大器的基础上, 推导了描述增益竞争双波长放大单频掺镱双包层光纤放大器的稳态速率方程组, 建立了增益竞争双波长放大单频光纤放大器的理论模型; 利用建立的理论模型模拟分析了信号光波长间隔、 信号光种子功率比、 抽运方式和增益光纤长度等因素对放大器的单频激光输出 效率以及SBS抑制效果的影响.     

间隔可调多波长光纤激光器的实验研究

半导体光放大器(SOA)的非均匀加宽特性对产生多波长激光非常有利。本文对两段式立奥-萨尼亚克(Lyot-Sagnac)滤波器进行了详细的理论分析,实现了一种基于半导体光放大器的新型多波长光纤激光器。它利用立奥-萨尼亚克滤波器的波长选择性,在室温下得到了约18个具有30 dB信噪比的多波长激光输出。波长范围1556~1577 nm。通过调节立奥-萨尼亚克环内的偏振控制器,多波长激光的波长间隔可在两种国际电信联盟(ITU)标准波长间隔(0.4 nm和0.8 nm)间选择。这种构型的光纤激光器具有稳定性好、波长间隔可控、信噪比高等优点。     

Eye-safe,single-frequency pulsed all-fiber laser for Doppler wind lidar

A single-frequency pulsed erbium-doped fiber(EDF) laser with master-oscillator power-amplifier configuration at 1 533 nm is developed. A short-cavity,erbium-doped phosphate glass fiber laser is utilized as a seeder laser with a linewidth of 5 kHz and power of 40 mW. The seeder laser is modulated to be a pulse laser with a repetition rate of 10 kHz and pulse duration of 500 ns. The amplifier consists of two pre-amplifiers and one main amplifier. The detailed characteristics of the spectrum and linewidth of the amplifiers are presented. A pulse energy of 116 μJ and a linewidth of 1.1 MHz are obtained. This laser can be a candidate transmitter for an all-fiber Doppler wind lidar in the boundary layer.     

High-power superfluorescent source with a side-pumped Yb-doped double-cladding fiber

A compact supe uorescent source based on an Yb-doped double-cladding fiber amplifier is described. The packaged amplifier is pumped at 975 nm by side-coupling emission from a 2.0-W broad-stripe laser diode through an imbedded V groove. The fiber source generates 485 mW of broadband emission centered at 1055 nm with a 41-nm FWHM flat power spectrum.     

Microstructured polymer fiber laser

A microstructured polymer optical fiber doped with Rhodamine 6G dye was fabricated and demonstrated as an optical amplifier and a fiber laser. As an amplifier, the fiber achieved a gain in excess of 30 dB. As a pulsed fiber laser, the fiber exhibited a threshold of 20 microJ, a slope efficiency of 18%, and a lifetime as high as 130,000 shots at 10 Hz. The maximum output energy was 16 microJ. The advantages that such fibers offer lie in the simplicity and flexibility of their fabrication and in their potential for use as compact, tunable solid-state sources.     

(1+1)型长距离侧面泵浦光纤实现17.4 kW激光输出

长距离侧面泵浦激光光纤在泵浦光注入、热管理、非线性抑制等方面具有天然优势,是实现高功率激光输出的有效途径。研制了（1+1）型长距离侧面泵浦激光光纤,采用1018 nm同带泵浦反向注入方式实现了17.4 kW激光输出,斜率效率为82.1%,3 dB线宽为1.3 nm,拉曼抑制比为37.8 dB。研究结果展示了长距离侧面泵浦光纤作为数十千瓦光纤激光放大器增益介质的巨大应用潜力。     

Multiwavelength fiber laser using S-band erbium-doped fiber amplifier and semiconductor optical amplifier

A multiwavelength fiber ring laser that is based on an S-band erbium-doped fiber amplifier (EDFA) and a semiconductor optical amplifier (SOA) is developed. An optical switch is used to switch the multiwavelength fiber laser between S-band and L-band. This fiber laser can stably lase seven wavelengths in the S-band or 28 wavelengths in the L-band. Additionally, the lasing wavelengths with a signal-to-noise ratio of over 33 dB and a wavelength spacing of 100 GHz are demonstrated experimentally. The average powers of the lasing wavelength in the S-band and the L-band are −7.53 and −12.15 dBm, respectively.     

Multiple-Output Fiber-Ring Lasers and Amplifiers in a Hybrid CATV and ADSL Broadcasting Optical Fiber Communication System

In this article we propose two kinds of new fiber ring structure with a semiconductor optical amplifier. The first structure is a one-fiber-ring amplifier with an 8 × 8 fiber coupler and a semiconductor optical amplifier (SOA). The second fiber ring structure is a two-fiber-ring laser including an 8 × 8 fiber coupler, a 2 × 2 E/O modulator, and an SOA. The 14-output spectra of the fiber laser are measured. The gain coefficients of each port of the multiple-output-fiber-ring amplifiers are also measured. We apply these two kinds of fiber ring structures in a hybrid CATV and ADSL broadcasting optical fiber communication system. This application can develop a broadcasting system with large coverage area without using many laser diodes and optical amplifiers. The performance of such a system is also analyzed in this article.     

国产光纤实现直接抽运全光纤化3000 W级激光输出

基于国产光纤构建了直接抽运全光纤化主控振荡器功率放大器结构光纤激光器, 放大级分别采用武汉烽火锐光科技有限公司和中国电子科技集团公司第四十六研究所提供的国产20/400 μm掺镱双包层光纤作为增益光纤, 通过全国产化放大级实现了3050和3092 W的1080 nm激光输出. 放大级提取效率分别为67.3%和68.2%, 光-光效率分别为63.0%和63.9%. 据可查询资料, 这是公开报道的直接抽运全光纤激光输出的最高水平, 同时由于采用了国产光纤作为放大级增益光纤, 表明国产光纤具备了3 kW级光纤激光器输出能力. 通过国产光纤横截端面以及光纤熔接显微镜图像实验分析知, 光纤制造工艺的不足是导致国产光纤激光器效率低的主要原因. 继续改进光纤工艺, 提升抽运功率, 优化光纤长度, 有望实现更高功率的全国产化光纤激光器输出.     

高功率宽带射频调制连续激光源

射频强度调制激光作为激光雷达系统的载波可以有效提高系统的抗干扰和抗散射能力,高功率宽带射频强度调制光源是实现高分辨率远距离探测的关键.本文采用在Nd:YAG激光器的耦合腔中插入一对四分之一波片的方法实现了频差调谐范围为30 MHz—1.5 GHz的双频激光输出,结合光纤振荡功率放大技术,将双频信号光功率放大为50 W.耦合腔双频种子源具有良好的功率和频率稳定性,输出功率为9.5 mW时,功率标准差为0.145 mW,稳定性为1.52%,输出双频激光的频差为250 MHz时,拍频的标准差为1.6144 MHz.种子光进行三级光纤功率放大,得到50 W双频激光输出.放大后的双频激光功率波动范围小于0.1 W,双频拍频的标准差为1.777 MHz,很好地保持了放大之前的功率稳定性和双频频差稳定性.     

All-fiber design of hybrid Er-doped laser/Yb-doped amplifier system for high-power ultrashort pulse generation

We propose a design of an all-fiber laser system that combines the most advanced Er:fiber laser in the telecommunication range and an efficient Yb-doped amplifier for generation of high-power ultrashort pulses. The system is based on nonlinear wavelength conversion of 1.56 μm ultrashort Er:fiber laser pulses to the 1 μm range in a short pigtail of dispersion-shifted silica fiber with subsequent amplification in the Yb-doped fiber amplifier. Pulses with a duration as short as 85 fs and averaged power of 200 mW are demonstrated.