Wavelength-switchable single-frequency erbium-doped fiber ring laser

We demonstrate a single-frequency and wavelength-switchable fiber ring laser obtained by a Lyot filter used in combination with a sampled fiber Bragg grating and a saturable absorber. The operating wavelength of the laser can be tuned, with a constant 0.8-nm step, in the range 1552.6-1555.8 nm. The tuning mechanism works on the rotation of the polarization of Lyot filter input signal. The structure of the laser is very simple regarding its characteristics: an output power of 6 dBm, with a signal-to-noise ratio higher than 60 dB and a spectral linewidth of 8 kHz.     

可调谐单频掺镱光纤DBR激光器

对分布布拉格反射(DBR)的透射特性进行了分析,制作了一个单频窄线宽掺镱光纤DBR激光器.在977 nm半导体激光器泵浦下,在1052.5 nm波长处输出功率可达4 mW,线宽小于8 MHz(受测量仪器分辨率限制).采用弧形梁调谐光纤光栅,实现了DBR光纤激光器在单纵模工作状态下的连续调谐,调谐范围可达20.4 nm(1036.1～1056.5 nm),并研究了调谐对激光器的泵浦阈值和斜率效率的影响.     

1550 nm全光纤单频脉冲光纤激光器

设计并实现了一种基于人眼安全波段的1550 nm全光纤化结构单频脉冲光纤激光器。激光器采用外腔稳频技术的单频半导体激光器作为种子源,其线宽1.8 kHz,功率20 mW。通过预放大器和声光调制器获得单频脉冲激光,并运用两级光纤放大器实现了线宽1.9 kHz、平均功率521 mW、脉冲宽度200 ns、重复频率10 kHz的单频脉冲光纤激光输出。输出脉冲峰值功率达260 W。输出端采用了双包层单模光纤,保证了输出激光的光束质量。整个激光器通过对种子光级联放大,结合放大器的增益控制,成功抑制了受激布里渊散射(Stimulated Brillouin Scattering,SBS)效应,消除了放大过程中噪声对线宽的影响,获得了线宽稳定的单频脉冲激光。     

Continuous-wave and giant-pulse operations of a single-frequency erbium-doped fiber laser

We present a compact diode-pumped single-frequency single-polarization erbium-doped fiber laser with fiber Bragg gratings (FBGs) written in the active fiber itself. The single-polarization regime was obtained by applying uni-axial stress to one of the two FBGs forming the cavity. The laser is shown to operate in two regimes-quasi-continuous-wave regime with a few-percent of modulation in the output power and a giant-pulse regime accessible under sinusoidal pump modulation.     

保偏光纤饱和吸收体单频窄线宽光纤激光器

研制了一种基于保偏(PM)光纤可饱和吸收体结合光纤光栅Fabry-Perot(FBG F-P)标准具的单频窄线宽光纤激光器.该激光器以高增益掺Er3+光纤(EDF)作为增益介质,采用行波环形腔消除空间烧空效应,并结合FBG F-P标准具选模,实现激光器单频运转.用一段PM EDF作为可饱和吸收体抑制跳模,以获得高效、稳...     

Experimental measure of dynamic spatial-hole burning in DFB lasers

Spatially resolved measurements of carrier density in two 1.3-μm distributed feedback laser diodes are reported. By measuring the response of the spontaneous emission intensity to a 50-MHz drive current, small relative changes in the carrier density can be observed. When biased below threshold, the carrier density fluctuates uniformly in the laser cavity with a phase delay corresponding to the carrier lifetime. When biased above threshold, the carrier density response shows clear evidence of spatial hole burning. The location of the minimum and the net change in carrier density, however, depend on the particular laser     

Cancellation of associated frequency dithering in a single-frequency compound-ring erbium-doped fiber laser

The stabilizing mechanism of a single-frequency compound-ring erbium-doped fiber laser is greatly improved by canceling the associated frequency dithering. This is achieved by exploiting the filter feature of an optical fiber compound-ring resonator to produce a net resultant intensity modulation. The theory of this cancellation method, derived from the phase resonant condition of the compound-ring resonator, shows that a full cancellation of the frequency dithering can be attained when two antiphase dithers are applied. Experimentally, the frequency jitter of the laser is greatly suppressed and the linewidth is less than 5 kHz.     

Widely tunable single-frequency Er-doped fiber laser with longlinear cavity

A widely tunable single-frequency Er-doped fiber laser is demonstrated in a 21-m-long linear cavity incorporating all-fiber acoustooptic frequency shifters and a saturable absorption grating. Stable single-frequency operation is achieved with a sidemode suppression ratio higher than 50 dB and a wavelength tuning range greater than 40 nm     

345-mW 1836-nm single-frequency DFB fiber laser MOPA

We demonstrate an in-band-pumped continuous-wave single-frequency distributed-feedback (DFB) fiber laser emitting at a wavelength of 1836 nm with an output power of /spl sim/5 mW. The laser is subsequently amplified to 345 mW using a master-oscillator power amplifier configuration. To the best of the authors' knowledge, this is the first report of a Tm-co-doped single-frequency DFB fiber laser that is in-band pumped at 1565 nm. The laser is confirmed to operate in a single mode, using a scanning Fabry-Pe/spl acute/rot interferometer.     

Characterization of wavelength-tunable single-frequency fiber laser employing acoustooptic tunable filter

This paper demonstrates and characterizes a novel wavelength-tunable single-frequency erbium-doped fiber ring laser incorporating an all-fiber acoustooptic tunable bandpass filter and a self-constructed saturable absorption grating (SAG). Stable single-longitudinal-mode operation was achieved over the wavelength range of 48 nm with a sidemode suppression ratio higher than 50 dB. The wavelength tuning characteristics, and the laser dynamics in wavelength switching and sweeping are analyzed in detail. A theoretical analysis on the effect of the SAG is also described.     

基于MOPA结构的1550 nm单频脉冲光纤激光器

人眼安全的1550 nm全光纤单频脉冲激光器具有广泛且诱人的应用前景。本文所研制的激光器采用全光纤主振荡功率放大(MOPA)结构和腔外声光调制的方法,一级预放大级采用1.5 m单模保偏掺铒光纤,输出功率21.45 mW;二级预放大级采用1.5 m双包层保偏铒镱共掺光纤,输出功率253.6 mW;功率放大级采用1 m双包层保偏大芯径铒镱共掺光纤,泵浦功率15.9 W时,最终实现了输出功率2.6 W、脉宽260 ns、重复频率10 kHz的单频脉冲激光输出。通过对各级增益光纤和无源光纤的长度优化,成功抑制了放大自发辐射(ASE)和受激布里渊散射(SBS),消除了放大过程中噪声的影响,得到了峰值功率1 KW的稳定单频脉冲特性。     

基于CPM-FBG的单频窄线宽DFB光纤激光器

利用电弧放电对光纤Bragg光栅(FBG)折射率的调制作用,提出了基于折射率周期调制(CPM)FBG的单频窄线宽分布反馈(DFB)光纤激光器方案。建立了CPM-FBG的数学模型并进行了仿真,验证了CPM-FBG的相移光栅特性;在掺铒光纤(EDF)上制作出CPM-FBG,形成了DFB单频窄线宽光纤激光器,激光器阈值功率为25.4mW,3dB线宽为805Hz,边摸抑制比大于48.8dB。     

Frequency pulling in a Brillouin fiber ring laser

The lasing frequencies of a Brillouin fiber ring laser are shifted slightly from the resonant frequencies of the cold fiber ring resonator due to the optical Kerr effect and the nonlinear phase shift associated with stimulated Brillouin scattering (SBS) used as the gain mechanism in this type of laser. These frequency pulling effects are investigated in detail both theoretically and experimentally. The results of this study are useful in many Brillouin fiber ring laser applications such as Brillouin fiber optic gyroscopes, microwave generators, and frequency shifters. To the authors' knowledge this is the first time the frequency pulling effect caused by the nonlinear phase shift associated with SBS is reported     

60 mW 1.5 μm single-frequency low-noise fiber laser MOPA

The operating characteristics of an efficient 60 mW, single frequency, low noise integrated master oscillator power amplifier (MOPA) with active noise suppression is presented. With active noise reduction this source demonstrated a maximum relative intensity noise of -110 dB/Hz below the CW lasing level in the relaxation oscillation regime and a broadband RMS noise of 0.39% with respect to the CW lasing level in a 2 MHz bandwidth     

基于多模光纤偏振烧孔效应的双波长掺铒光纤激光器

基于多模光纤(MMF)引入的偏振烧孔(PHB)效应,研制了一种环形双波长掺铒光纤(EDF)激光器.单模光纤(SMF)-MMF-SMF组成的结构使MMF不同偏振方向的反射模在波长上分开,利用PHB效应实现双波长的输出,输出波长间隔可通过改变MMF的长度改变.实验对比了1.6 m和3.0 m长的MMF输出波谱特性,结果表明...     

单频光纤激光技术的研究进展（特邀）

单频光纤激光具有单色性好、谱功率密度高等特点,在通信传感、雷达、引力波探测、非线性频率变换等领域有广泛的应用需求。目前单频光纤激光技术正朝着更高功率、更宽波段和更高性能等方向发展,是激光技术领域的研究前沿和热点。文中系统梳理了近年来单频光纤激光领域取得的重要进展,具体从单频激光实现方式、功率增长、波长拓展以及性能提升等方面对相关标志性工作进行了总结,讨论了单频光纤激光技术当前所面临的挑战,并展望了其未来发展趋势。     

一种新颖的自反馈光注入单频窄线宽光纤激光器

报道一种基于自反馈光注入的单频窄线宽光纤激光器。激光器采用线形腔结构,用高掺杂Er3+光纤作为增益介质,利用输出信号光分束反馈与腔内振荡激光干涉,形成折射率光栅与增益光栅共同作用选择纵模,获得稳定的1 549.85 nm单频窄线宽激光输出。在975 nm单模激光二极管(LD)抽运下,激光器的抽运阈值光功率为13 mW。当抽运光功率为112 mW时,最大输出信号光功率为30.6 mW,对应的光-光转换效率为27.3%,斜率效率为30.2%,信噪比大于50 dB。采用延时自外差方法测量线宽,当使用30 km单模光纤延迟线时,测量得到激光器的3 dB线宽为4.0 kHz。     

Characteristics of a single-frequency Michelson-type He-Ne gas laser

A new mode suppression configuration is described for producing a single-frequency output from gaseous lasers. This configuration has the form of a modified Michelson interferometer where the basic modification is in the introduction of a third feedback mirror for coupling the two branches of the Michelson. Small path length differences between the two branches of the Michelson are responsible for the mode suppression properties of the device which come about through interference phenomena at the beam splitter. This results in a frequency-dependent power loss out of the beam splitter which can provide for large amounts of mode discrimination. The device is made into an oscillator by introducing gain into each of the two branches of the Michelson. A detailed analysis of the device is given based on the scattering matrix formalism. The results of the analysis give the oscillation frequencies, the degree of mode discrimination, the internal laser radiation intensity, and equations for the output power. Experimentally, a 10 mW single-mode 6328 Å He-Ne Michelson-type gas laser is described. Data on the frequency spectrum, output power, and amplitude stability of a free running laser are given and correlated with theory. While it is shown that single-frequency operation is easily obtained, the device in its present form does not include a means for stabilizing the frequency.     

高功率单频掺铒光纤激光技术研究进展（特邀）

近年来,在相干探测、激光雷达、激光冷却以及引力波探测等领域应用需求的驱动下,窄线宽、低噪声的高功率单频掺铒光纤激光技术成为国内外光纤激光技术领域的研究热点。简要介绍了近些年高功率单频掺铒光纤激光技术的研究进展,包括单频掺铒光纤激光器和高功率单频掺铒光纤放大器,分析了高功率单频掺铒光纤激光的发展趋势和面临的挑战,并对下一步的发展方向进行了展望。     

Stabilized single-frequency output from a long ring laser

A technique for obtaining high-power single-frequency output from a long ring laser is described and demonstrated. A double feedback system is discussed, which stabilizes the laser frequency with respect to the center of the atomic gain curve. Experiments are reported which demonstrate the existence of a narrow atomic-line-center discriminant. The extension of this technique to dc-excited ion lasers is discussed.