级联复合腔对光纤激光模式的抑制影响

提出了一种复合腔结构的稳定单纵模(SLM)掺铒光纤激光器,其复合腔结构由主环形有源腔和两个次级无源腔组成。在光纤环形镜中嵌入未抽运的掺铒光纤作为可饱和吸收体以抑制多纵模,用光纤环谐振腔作为滤波器抑制拍频噪声,用光纤光栅作为波长选择器件,最终得到了单纵模输出并消除了拍频噪声。在整个波长调节范围内边模抑制比大于50dB,当泵浦功率为80mW时,掺铒光纤激光器输出功率为20.51mW,激光器的输出很稳定,在25min的观察时间内,输出功率的变化小于0.02%,实现了稳定的激光功率输出。     

基于角度调谐F-P干涉仪的C波段可调谐激光器的研究

研究了基于法布里一珀罗(F-P)干涉原理的角度调谐的滤波器特性,使用自制的滤波器进行可调谐掺Er^3 光纤激光器实验。当980nm泵浦功率为30mW时获得了稳定的单纵模激光输出,输出功率约。0.65mW,线宽低于0.1m,在35．76nm波长调谐范围内功率变化不超过1dB,边模抑制比(SMSR)大于35dB;泵浦功率为46mW时获得了最大的输出功率,约为1mW。     

DBR单纵模光纤激光器波长温度调谐

报道了采用DBR方式,利用8 mm的高浓度掺Yb3+单模光纤,实现了波长为1 064 nm的单纵模调谐激光稳定输出的实验结果。该DBR谐振腔有效腔长为16 mm,输出最大功率为7.4 mW,通过半导体制冷器温控改变谐振腔的温度,实现了0.824 nm的单纵模无跳模调谐。采用光纤外差法,并利用低损耗环形器和光纤反射镜倍增延迟线长度提升测量精度的方式,测量得到激光最大线宽为4.4 kHz。单纵模激光的弛豫震荡峰位于900 kHz处,其相对强度噪声为-110 dB/Hz,当频率大于1.5 MHz时相对强度噪声为-145 dB/Hz。     

基于F-P干涉技术的通信波段可调谐激光器

根据F-P干涉原理设计制作了楔型F-P滤波器,使用这种滤波器进行可调谐掺铒光纤激光器实验,980nmLD泵浦功率为25mW时获得了稳定的单纵模激光输出,输出功率约0．6mW,线宽低于0．06nm,在34．2nm波长调谐范围内功率变化不超过0．5dB,边模抑制比大于35dB。     

低阈值光纤激光器稳频特性研究

为了实现低阈值光纤激光器的频率稳定输出,设计了环形腔光纤激光器,以光纤光栅作为波长选择元件,在未泵浦光纤饱和吸收体和其锥形化结构的协同作用下实现激光纵模选择,获得了短光纤饱和吸收体长度下的单纵模激光稳定输出。介绍了未泵浦光纤饱和吸收体选频原理和锥形结构滤波原理,实验研究了不同光纤饱和吸收体长度下激光纵模特性和波长稳定性,以及锥形化光纤饱和吸收体的激光输出特性。实验表明,引入锥形化结构的饱和吸收体后,激光器能够稳定输出1545 nm波长的单纵模激光,并有效降低光纤激光器阈值至7.58 mW,采用延迟自外差方法测得该光纤激光器的线宽小于8 kHz。     

应力对相移DFB光纤激光器输出特性的影响

通过对相移DFB激光器的光栅中心位置部分施加应力,可以使得相移光纤DFB激光器工作在单纵模单偏振状态下.在远离中心位置施加应力, 可使得相移DFB激光器成为具有单向取向输出的激光器. 掺Yb3+光纤参数如下:光纤芯径为6.10 μm,截止波长为907 μm.对975 nm的吸收为68 dB/m.相移光纤光栅制作在Yb3+光纤上,长度为10 cm, 相移在光纤光栅的中间.实验所用抽运源为波长为976 nm的带尾纤的半导体激光器,抽运光经WDM进入DFB光纤激光器,激光器运行在1053 nm. 在未加应力前,当抽运功率为78 mW时,DFB激光器的两端最大输出功率为216 μm±10%.用自由光谱范围为640 MHz,精细度为20的扫描F-P干涉仪测量其光谱图, 发现激光运行在双偏振输出状态,用格兰棱镜测量激光输出的偏振特性,消光比仅为1.6 dB. 对光纤光栅的中心位置施加一个应力,这时从扫描F-P所测的光谱来看,激光输出为稳定的单纵模单偏振输出,用格兰棱镜测量其消光比为14 dB,当抽运功率为78 mW时,最大输出功率抽运端达到356 μW,另一端为230 μW. 对离光纤光栅相移区的位置为1cm的地方施加同样的应力,从上述F-P干涉仪所测的光谱来看,激光输出为单纵模输出.格兰棱镜所测消光比为4.14 dB.抽运端最大输出为800,另一端为112. 对离光纤光栅相移区为2 cm的地方施加应力,从扫描F-P干涉仪来看,激光输出为单纵模输出,用格兰棱镜所测消光比为1.47 dB,抽运端最大输出为932 μW,另一端为83 μW.(OC10)     

准共线声光可调谐掺铒光纤激光器的研究

提出了一种新颖的单纵模、单偏振的可调谐掺铒光纤激光器结构。使用准共线型声光可调谐滤波器作为调谐元件。利用饱和吸收效应在未泵浦低掺铒光纤中形成自写入瞬态光栅,用以压窄输出激光的线宽,并且有效地防止跳模。理论计算表明:当泵浦功率为100mW时,激光器的输出功率可达5.5mW,输出线宽在10-4nm量级。这些数据对后续的实验研究有指导作用。     

单纵模波长可开关的环形腔光纤激光器

提出并实现了一种单纵模窄线宽输出、波长可开关的光纤激光器.该激光器采用环形腔结构,利用一段未抽运的掺铒光纤(EDF)的饱和吸收效应来实现光纤激光器的单纵模运转与窄线宽输出;同时利用1×2光开关和2个并联的不同中心波长的光纤光栅(FBG)的选波作用,通过控制光开关的电压信号,实现2个输出波长的可开关功能.在17.5 dBm的掺铒光纤放大器(EDFA)输出功率下,获得了2.5 dBm峰值功率,3 kHz线宽的单纵模激光输出;并且输出光的波长在控制电压的作用下可在1545.2 nm和1556.4 nm两个波长之间任意选择.     

掺Yb相移分布反馈光纤激光器的后期制作与研究

采用二次曝光法先在一根10cm长的掺Yb光纤上制作出近似λ/4相移分布反馈(DFB)掺Yb光纤激光器。再利用紫外修整的方法,同时通过F-P扫描干涉仪及示波器实时监控激光运行模式,获得了阈值低而单纵模运行特性好的λ/4相移DFB掺Yb光纤激光器。所制作的激光器阈值为20mW。当抽运功率为130mW时,获得了25mW的1053um单纵模激光。     

窄线宽高效率的全光纤Yb^3＋激光器

利用光纤布拉格光栅（FBG）作为腔镜，研制了一种全光纤结构的掺Yb^2 光纤激光器。以泵浦波长978nm的LD作为抽运算，在1060.4nm波段获得了0.14nm的窄线宽激光输出。实验中发现掺Yb^3 光纤长度对激光器的阈值及输出功率均有影响，但光纤激光器的输出线宽保持不变。最大激光输出功率为2.36mW，斜率效率达到22.2%。     

Novel performance of fiber lasers: tunable operation in visible range

A review of the main physical processes important for frequency doubling of fiber lasers and the results of development by the Novosibirsk group of the fiber lasers operating from blue-green to yellow-red spectral ranges with a potential of the broad continuous tuning are presented. These lasers with ～100 mW power are treated to be attractive light sources for applications in medicine, especially in confocal microscopy and flow cytometry.     

光纤激光器的相干输出

研究了两路光纤激光的相位锁定和相干输出, 用融锥光纤耦合器实现了两路高掺铒光纤激光之间的相互耦合。提出了在激光器高反射率前腔镜的前面加融锥光纤耦合器的方法构成简单的共振腔, 从而实现两路光纤激光的相干叠加。开展了基于融锥光纤耦合器互注入锁相的两路光纤激光器的相干合成实验, 成功实现了两路光纤激光器的注入锁定, 观察到了波长锁定（中心波长稳定在1549.8 nm, 线宽为0.08 nm）、远场干涉条纹和线宽压缩现象。分析了单个激光器和激光器阵列的斜率效率, 当反射率为70%, 抽运功率均为145 mW时, 获得最大合成功率为127 mW。     

光纤激光外腔频谱组束的实验研究

实验中采用激光二极管作为泵浦源、大模面积Er3+Yb3+共掺双包层光纤作为增益介质,利用傅里叶变换透镜、闪耀光栅和输出耦合镜组成的外腔结构,实现了两路Er3+Yb3+共掺双包层光纤激光器的频谱组束。在单路光纤激光器的最大输出功率为520 mW和545 mW、光栅衍射效率为80%的条件下,获得了690 mW的组束功率,组束效率为65%,同时对组束激光的光束质量进行了评估。测得水平和垂直方向的光束质量因子分别为M2x=1.592,M2y=1.335。     

Semiconductor pump laser technology

Recent progress in high-power semiconductor lasers for erbium-doped fiber amplifiers is described, focusing on 1.48-μm InGaAsP/InP lasers and 0.98-μm InGaAs/GaAs lasers. The experimental output powers exceed 200 mW (the maximum power was 325 mW) for 1.48-μm lasers, and simulation results indicate that over 400 mW could be obtained by optimizing parameters in strained-layer (SL) multiple-quantum-well (MQW) lasers. Stable operation over a few thousand hours under 100-mW power is demonstrated for liquid-phase-epitaxy-grown lasers, MQW lasers, and SL-MQW lasers grown by all-metal organic vapor-phase epitaxy (MOVPE). For 0.98-μm lasers, improvement in the fiber coupling efficiencies and long-term reliabilities are described. Their power coupled into a single-mode fiber has reached over 100 mW, with coupling efficiencies of approximately 40%. Although reliability seems to be one of the drawbacks compared with 1.48-μm lasers, stable operation for over 10,000 h at 50°C and 30 mW has been reported     

High-power aging tests of 1.3 and 1.5 ?m VIPS lasers

1.3 and 1.5 ?m VIPS lasers were tested under high-power aging levels up to 130 mW. The output powers of the lasers were enhanced by AR/HR-coating of facets and optimisation of cavity lengths. Aging power levels were 75% of ?Pmaxand were up to 130mW at 25°C and up to 90 mW at 70°C for 1.3?m VIPS lasers. The median lifetimes were estimated to be 150,000 h at 25°C and 60,000 h at 70°C. For the 1.5?m VIPS lasers, the aging power levels were up to 90 mW at 25°C and up to 50 mW at 70°C. Median lifetimes of about 60,000 h and 45,000 h for 25 and 70°C aging tests, respectively, were achieved.     

High temperature, high power InGaAs/GaAs quantum-well lasers withlattice-matched InGaP cladding layers

The authors report the high-temperature and high-power operation of strained-layer InGaAs/GaAs quantum well lasers with lattice-matched InGaP cladding layers grown by gas-source molecular beam epitaxy. Self-aligned ridge waveguide lasers of 3-μm width were fabricated. These lasers have low threshold currents (7 mA for 250-μm-long cavity and 12 mA for 500-μm-long cavity), high external quantum efficiencies (0.9 mW/mA), and high peak powers (160 mW for 3-μm-wide lasers and 285 mW for 5-μm-wide laser) at room temperature under continuous wave (CW) conditions. The CW operating temperature of 185°C is the highest ever reported for InGaAs/GaAs/InGaP quantum well lasers, and is comparable to the best result (200°C) reported for InGaAs/GaAs/AlGaAs lasers     

UV generation by frequency quadrupling of a Yb-doped fiberamplifier

The pulsed output of a Yb-doped fiber amplifier was frequency doubled and quadrupled to generate visible and UV radiation. When pumped with 150-200 mW at 980 nm and seeded at 1064 nm, the amplifier produced an average power of 90 mW at 1064 nm, 45 mW at 532 nm, and 1.4 mW at 266 nm. These results indicate that frequency-converted fiber lasers and amplifiers will be able to replace conventional tunable UV sources (e,g,, frequency-converted dye lasers) in a number of applications     

基于氧化石墨烯被动锁模的窄线宽皮秒脉冲掺铒光纤激光器

报道了用氧化石墨烯作为可饱和吸收体的全光纤结构皮秒脉冲掺铒光纤激光器。该激光器的线形谐振腔由窄带的光纤布拉格光栅和氧化石墨烯可饱和吸收镜构成。当抽运功率为22mW时,实现了稳定的重复频率为5.82MHz的锁模激光脉冲输出,脉宽为87ps,光谱中心波长为1549.3nm,3dB谱宽为0.06nm,信噪比为66dB。     

Littman光栅外腔可调谐Yb3+双包层光纤激光器

本文对LD泵浦的光栅外腔可调谐双包层Yb3 光纤激光器进行了实验研究．采用Littman外腔结构，研究了Yb3 光纤激光器的调谐特性．输出激光调谐范围42nm，谱线宽度0．08nm，最大输出功率达到了460mW，斜率效率约30％．并对其输出光功率随波长的变化进行了观测和分析．     

The influence of power level on injection laser linewidth andintensity fluctuations including side-mode contributions

The contribution of side modes to the main-mode line-width is calculated as function of power output using analytic relations and verified using a series of Monte Carlo calculations. For well-behaved lasers having photon lifetimes of 0.88 and 1.57 ps and gain compression of 10% or less, it is found that the total linewidth decreases monotonically with increasing power output. These lasers have main-mode to side-mode ratios in the range 100-300 at 3 mW output; they exhibit side-mode contributions to main-mode linewidth of 17 and 57% respectively at a power level of 10 mW and modal ratios of 940 and 390. When the gain compression exceeds 10% as it may in lasers running at 10 mW or more, the linewidth can reach a minimum and then increase with increasing power level, in accordance with laboratory observation on some lasers