Linear-cavity fiber laser in nearly single-frequency operation using Faraday rotator mirror

A nearly single-frequency selection is realized in a linear-cavity fiber laser constructed using a Faraday rotator mirror (FRM) and a partial reflectance fiber Bragg grating (FBG) as the cavity ends. At 1552.46 nm wavelength, the measured optical signal-to-noise-ratio (OSNR) is 58.5 dB with a linewidth less than 400MHz obtained using a subring cavity and a polarization controller as the mode filters. The pumping efficiency is improved by 10% by recycling the residual pump power to the gain medium.     

Single-longitudinal-mode linear-cavity fiber laser using multiple subring-cavities

A single-longitudinal-mode selection is realized in a linear-cavity fiber laser construction using a loop-back optical circulator and a partial reflectance fiber Bragg grating as the cavity ends. At 1551 nm wavelength, the measured signal-to-noise-ratio is 56 dB and with a line width less than 1 MHz obtained using multiple subring cavities as mode filters. The pumping efficiency is 10% improved by recycling the residual pump power to gain medium.     

Er-doped fiber ring laser gyroscopes operating in continuous waves

A direction related polarizer was inserted into a ring laser cavity to eliminate one of the two eigen-modes as well as spatial hole burning of the gain medium in a bidirectional Er-doped fiber ring laser. Thus, a fiber ring laser gyroscope (FRLG) operating in continuous wave was demonstrated. A beat signal of over 30-dB noise was observed and a good inear relation between the beat frequency shift and cavity rotation rate was obtained.     

Linear-cavity fiber laser using subring-cavity incorporated saturable absorber for single-frequency operation

By using a subring cavity incorporated with a saturable absorber, a stable single-frequency selection is realized in a linear-cavity fiber laser, which is constructed using a broadband fiber mirror and a partial reflectance fiber Bragg grating as the cavity ends. At 1550.33 nm, the laser has an optical signal-to-noise-ratio of >53.28 dB and with linewidth less than 1 MHz. The pumping efficiency is 25% improved by recycling the residual pump power to gain medium. The power stability and wavelength stability have also been studied.     

Multiwavelength fiber ring lasing by use of a semiconductor optical amplifier

A multiwavelength fiber ring laser obtained by use of a semiconductor optical amplifier (SOA) with a simple laser cavity configuration is reported. A Fabry-Perot filter was used in the fiber laser ring cavity to achieve more than 50 simultaneous wavelength lasing oscillations with a frequency separation of 50 GHz. The resulting stable broadband multiwavelength lasing operation was attributed to broadband and flat gain of the SOA, which has a gain flatness of 0.8 dB for more than 20 nm. The laser has a total output power of -3 dBm and a signal-to-spontaneous-noise ratio of 30 dB.     

一种控制环形激光器光学腔长的新方法

提出了一种控制环形激光器光学腔长的新方法.该方法是利用压电陶瓷电控环形激光器毛细管内干燥空气的折射率,实现对环形激光器光学腔长的控制.这种控制方法对环形激光器性能影响很小,具有响应速度快、灵敏度高、功耗低等优点,可用于全反射棱镜式环形激光器、反射镜式环形激光器的稳频系统.对于激光陀螺、激光计量等应用具有重要意义.     

复合腔全光纤环形激光器单纵模双向同时激射的实验研究

提出并实验证实了三能级掺杂光纤复合腔环形激光器共振选模振荡原理和腔内自建可饱和吸收机制对双向行波共振谱的去耦作用，并实现复合腔掺Ｅｒ＾３＋全光纤环形激光器单纵蓦以向同时激射。     

850 nm centered wavelength-swept laser based on a wavelength selection galvo filter

A wavelength-swept laser is constructed using a free space external cavity configuration coupled with a fiberbased ring cavity at the 850 nm region. The external cavity filter employs a galvo-mirror scanner with a diffraction grating for wavelength selection. The filter is connected to a ring cavity through an optical circulator.The ring cavity contains a broadband semiconductor optical amplifier with a high optical output. The performance of this laser is demonstrated with broad bandwidths and narrow linewidths. The 3 dB linewidth and the bandwidth of this source are 0.05 nm(~20 GHz) and 48 nm, respectively. The maximum output power is 26 m W at 160 m A current.     

稳定可调谐的单纵模多环形腔掺铒光纤激光器

提出了一种多环形腔(MRC)结构的稳定可调的单纵模(SLM)掺铒光纤激光器,多环形腔结构由双环形有源腔和两个次级无源腔组成.这种激光器是利用光纤法布里珀罗可调滤波器(FFP-TF)以及光学光栅滤波器(OGF)两种滤波器和多环形腔结构相结合来共同选模.可实现波长调节范围为1528～1565 nm,在整个波长调节范围内边模抑制比大于44.53 dB,在1554 nm附近边模抑制比可以达到最大值51.18 dB, 输出功率为-8.84 dBm,通过应用多环型腔结构,激光器的输出很稳定,在18 min的观察时间内,中心波长的变化小于0.02 nm,输出功率的变化小于0.04 dBm,实现了稳定且可调谐的单纵模输出.     

Room temperature multiwavelength erbium-doped fiber ring laser using a highly nonlinear photonic crystal fiber

A multiwavelength laser source is demonstrated with a high power erbium-doped fiber amplifier as the gain medium. A highly nonlinear photonic crystal fiber (PCF) is inserted in the ring cavity to provide nonlinear gain by four-wave mixing. A Sagnac loop is incorporated in the ring cavity serving as a comb-like multichannel filter. The comparison between fiber ring laser without PCF and with PCF shows that the highly nonlinear PCF can generate a larger number of excited wavelengths and help stabilize the output power.     

大色散稳定腔长的光纤锁模激光器的锁模特性研究

报道了一种新型的采用大色散腔结构的光纤锁模激光器,它可以有效地克服激光器腔长抖动对锁模的不良影响,同时,实验中发现,该结构对超模噪声也有很好的抑制作用。完成了大色散控制,电光调制器调制的,稳定的光纤锁模激光器实验,得到形状为sech^2的光脉冲输出,脉冲宽度为7.6ps,脉冲带宽积为0．335。     

Fundamental frequency noise properties of extended cavity erbium fiber lasers

A multimode linear cavity and a single-mode unidirectional ring cavity fiber laser with meter-long cavity lengths are shown to exhibit frequency noise limited by fundamental thermodynamic noise from 100?Hz to 100?kHz. Their measured spectra agree closely with theoretically derived thermodynamic noise and the characteristic dependence of the frequency noise power spectrum on the inverse of the cavity length is observed. The unidirectional ring laser exhibits a frequency noise of 2?Hz/Hz(1/2) at 1?kHz, one of the lowest published values to date from a free-running laser. The multimode linear cavity laser is shown to be a suitable candidate for thermal-noise-limited, meter-long fiber laser strain sensors with a strain resolution of 14?f?/Hz(1/2) at 1?kHz.     

10 GHz regeneratively mode-locked semiconductor optical amplifier fiber ring laser and its linewidth characteristics

A 10 GHz regeneratively mode-locked semiconductor optical amplifier fiber ring laser with a picosecond pulse duration was newly constructed, and the linewidth change of a longitudinal mode was measured for various laser cavity lengths using a delayed self-heterodyne detection method. The detected line shape was approximately Gaussian for cavity lengths of 3.4-171 m. This result indicates that the laser linewidth depends strongly on thermal or acoustic cavity length fluctuations. The linewidth was proportional to the inverse square root of the cavity length, and a linewidth of 1.7 kHz was obtained for a cavity length of 171 m.     

Spectrum control and shaping of optical pulses in optical fibre interferometers

This paper discusses the use of single-mode fibre ring interferometers for injection laser line narrowing and for enhancement of optical emission power. The efficient launching into fibre ring interferometers of multi-frequency external cavity injection laser emission, in both the c.w. and mode-locking regime, has been achieved. Matching the optical lengths of the external cavity and fibre interferometer allowed the measurement of mode width of such a laser. A method is proposed for shaping optical pulses in fibre ring interferometers from constant intensity frequency modulated emission. The mode-locking regime of all-fibre external cavity injection lasers has been achieved.     

基于扫描激光的腔增强吸收光谱研究

介绍了一种建立在半导体激光扫描基础上的腔增强吸收光谱技术。简要介绍了从衰荡吸收光谱技术向腔增强吸收光谱的发展及腔增强吸收光谱的实验装置,实验证明能够将 DFB 型半导体激光与高精密光学谐振腔相结合,用简单的实验装置进行高灵敏、高分辨直接吸收光谱测量。实验中,激光器的输出波长用一台波长计精确测量,当激光器的输出频率与某一腔模的频率共振时,激光被耦合到一个用两块高反射率平凹透镜(在 1.572μm 附近,R~0.994)组成的 34cm 长的高精密光学谐振腔,通过测量激光透过谐振腔后的光强,得到了二氧化碳分子在6358.654cm-1附近的吸收光谱,探测灵敏度达到了 1.2×10-5cm-1。     

Unidirectional Single-Mode 532-nm Nd:YAG Laser Using Intracavity Frequency Doubling in Nonplanar Ring Geometry

Intracavity frequency doubling of a single-mode Nd:YAG laser using a nonplanar ring cavity is demonstrated. The nonplanar ring cavity consists of a Brewster-angled Nd: YAG crystal placed in a magnetic field, a KTP crystal, and two spherical mirrors. In this design the Nd:YAG crystal acts as both a nonreciprocal polarization rotator and a partial polarizer, and the nonplanar portion of the ring cavity, which is formed by a relative twist angle between the Brewster-angled end surfaces of the crystal, serves as a reciprocal polarization rotator. Eigenpolarization theory for the cavity configuration is presented and a suitable value of the relative twist angle for unidirectional operation is estimated. A single-mode output power of 22 mW at 532 nm is obtained with a 1.2-W diode laser at 809 nm and a laser linewidth of less than 100 kHz is inferred from a beat note frequency spectrum between two identical laser systems.     

Travelling-wave operation of a tunable cw dye laser

A ring cavity configuration for a tunable cw dye laser is described. A substantial reduction of the output bandwidth of the ring laser with increase in power for unidirectional or traveling-wave operation has been demonstrated. The advantages of the ring configuration for single-frequency operation of cw dye lasers are explored.     

A Microcomputer System for Automatic Mode Sweep of Ring Laser Angular Rate Sensor(Ring Laser Gyro)

On the basis of analysis and principles of the operational modes and mode sweep of a ring laser, a microcomputer system for automatic mode sweep of ring laser angular rate sensor is presented. A 0～300 V continuous adjusted power supply system for PZT used to accurately adjust the cavity lens of the ring laser also is described in the paper. The test result shows that the microcomputer system could solve the problem of automatic mode sweep of ring laser successfully.     

用声光调制器实现的1 W Nd∶YAG单纵模环形激光器

鉴于单向环形腔是目前获得较大功率单纵模激光最有效的方式之一,为使环形腔单向运行,需要在环形腔内插入对正反2个方向的光产生损耗差的光学元件。采用激光二极管泵浦Nd∶YAG晶体,用声光调制器作为光学二极管使环形腔单向运行,实现四镜矩形环形腔单纵模激光器。实验中谐振腔的稳定性由增益介质的热透镜保证,声光调制器给正反2个方向的光提供损耗差,这使得在竞争过程中有较大损耗的光不能运行从而获得单向输出。实验获得了连续功率1 W、光束质量因子M2为1.21 的1.06 m单纵模激光。     

A Microcomputer System for Automatic Mode Sweep of Ring Laser Angular Rate Sensor (Ring Laser Gyro)

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