A Low-Pump-Threshold Photonic Crystal Fibre Raman Laser

We investigate a photonic crystal fibre Raman laser using fibre Bragg grating pairs as cavity mirrors. The threshold pump power is up to 0.65 W by decreasing the cavity loss and using a photonic crystal fibre with high Raman gain coefficient. A maximum continuous-wave output power of 2. 7 W is obtained at the maximum incident pump power of 5.6 W. The corresponding optical conversion efficiency and the slope efficiency are about 48% and 56%, respectively.     

Two-Frequency Brillouin Fiber Laser Based on Bragg Grating Fabry-Perot Cavity

Abstract

A novel and simple two-frequency Brillouin fiber laser is presented. It is based on a fiber Fabry-Perot cavity with fiber Bragg gratings as reflectors. The model of stimulated Brillouin scattering in fiber grating–based Fabry-Perot resonator is investigated. The laser allows conversion efficiency of close to 100% and suppresses the higher-order Stokes waves. The theoretical prediction is presented and the experimental demonstration is realized.     

Single-frequency Brillouin distributed feedback fiber laser

We demonstrate a single-frequency Brillouin distributed feedback laser (DFB). The DFB laser cavity was a 12.4 cm long fiber Bragg grating with a π-phase shift offset from the grating center. It exhibited a threshold of 30 mW and conversion efficiency from pump to Stokes wave as high as 27%. Higher-order Stokes waves were suppressed by more than 20 dB. The Stokes output of the laser could be obtained in either the forward or backward direction, simply by changing the orientation of the offset of the discrete phase shift with respect to the pump propagation direction. The DFB laser operated over a pump frequency range of 1.2 GHz, more than 60 times larger than the SBS gain bandwidth.     

Two-Frequency Brillouin Fiber Laser Based on Bragg Grating Fabry-Perot Cavity

A novel and simple two-frequency Brillouin fiber laser is presented. It is based on a fiber Fabry-Perot cavity with fiber Bragg gratings as reflectors. The model of stimulated Brillouin scattering in fiber grating-based Fabry-Perot resonator is investigated. The laser allows conversion efficiency of close to 100% and suppresses the higher-order Stokes waves. The theoretical prediction is presented and the experimental demonstration is realized.     

基于光子晶体光纤中受激布里渊散射的光载波抑制

设计了一种基于光子晶体光纤中受激布里渊散射的载波滤波器.该滤波器利用两个环形器和一段光子晶体光纤构成了一个环形腔,这种腔结构有效地降低了光纤中受激布里渊散射的阈值.理论分析了光子晶体光纤载波滤波器对提高光调制深度和射频增益的影响.利用25 m的高非线性光子晶体光纤作为受激布里渊增益介质,当入射载波功率为70 mW时,微波光子信号的射频增益为5.38 dB,实验结果与理论计算相吻合.     

Subwatt threshold cw Raman fiber-gas laser based on H2-filled hollow-core photonic crystal fiber

We report on what is, to our knowledge, the first cw pumped Raman fiber-gas laser based on a hollow-core photonic crystal fiber filled with hydrogen. The high efficiency of the gas-laser interaction inside the fiber allows operation in a single-pass configuration. The transmitted spectrum exhibits 99.99% of the output light at the Stokes wavelength and a pump power threshold as low as 2.25 W. The study of the Stokes emission evolution with pressure shows that highly efficient Raman amplification is still possible even at atmospheric pressure. The addition of fiber Bragg gratings to the system, creating a cavity at the Stokes wavelength, reduces the Raman threshold power below 600 mW.     

Multiwavelength L-band fiber laser with bismuth-oxide EDF and photonic crystal fiber

A multiwavelength laser comb using a bismuth-based erbium-doped fiber and 50 m photonic crystal fiber is demonstrated in a ring cavity configuration. The fiber laser is solely pumped by a single 1455 nm Raman pump laser to exploit its higher power delivery compared to that of a single-mode laser diode pump. At 264 mW Raman pump power and 1 mW Brillouin pump power, 38 output channels in the L-band have been realized with an optical signal-to-noise ratio above 15 dB and a Stokes line spacing of 0.08 nm. The laser exhibits a tuning range of 12 nm and produces stable Stokes lines across the tuning range between Brillouin pump wavelengths of 1603 nm and 1615 nm.     

An Efficient Photonic Crystal Fiber-Based Brillouin Erbium Fiber Laser Using a Fiber Bragg Grating for Multi-Wavelength Generation

Abstract

An efficient multi-wavelength Brillouin erbium fiber laser is demonstrated using an improved configuration with a broadband fiber Bragg grating and a piece of photonic crystal fiber. The laser generates more than 55 lines of optical comb with a line spacing of approximately 0.09 nm in a 1,565-5 nm region using pump powers of 3 dBm and 150 mW for the Brillouin and 980-nm pumps, respectively. The Brillouin erbium fiber laser with a fiber Bragg grating's reflectivity of 50% obtained a higher number of comb lines compared to that of 99% reflectivity.     

Monochromatization of semiconductor laser diodes using one-dimensional photonic crystals

The results on the development of the single-frequency semiconductor laser with external cavity based on a fiber Bragg grating (one-dimensional photonic crystal) formed in a single-mode fiber waveguide are presented. Stable single-frequency lasing at a wavelength of 977 nm with a spectral half width of 0.2 nm is achieved with a laser power output of 350 mW. The temperature dependence of lasing parameters is studied.     

高效率599 nm Ba(NO3)2外腔喇曼激光器

橘黄色波段固体激光器在基于荧光探测的生物医学诊断和显示等众多方面有着广泛的实际应用. 报道了利用532 nm的Nd∶YAG倍频激光抽运外置喇曼腔内的硝酸钡晶体,获得高效率的599 nm橘黄色喇曼激光的实验结果.对外置喇曼腔实验装置和运转参量进行了优化,喇曼振荡腔由对二阶斯托克斯光有最优化反射率的腔镜构成,对实验中所得到的二阶斯托克斯喇曼激光脉宽压缩及出现双尖峰的现象进行了分析.当抽运光功率达到4.1 W时,获得二阶斯托克斯喇曼激光功率为710 mW,输出光中心波长为599.38 nm,半峰全宽（FWHM）为1.1 nm,激光器最大光光转换效率为17.5%,斜率效率为24.8%.     

Output Characteristics of High-Power Continuous Wave Raman Fiber Laser at 1239 nm Using Phosphosilicate Fiber

A high-power singlemode Raman fiber laser (RFL) with maximum output power of 4.11 W and maximum power conversion efficiency of 47.40% at 1239 nm is realized using continuous wave 8.4 W Yb-doped double-clad fiber laser as a pump, 700 m phosphosilicate fiber, and a Raman cavity formed by a pair of fiber Bragg grating mirrors at 1239 nm. The output characteristics of the RFL at 1239 nm for different fiber lengths and output mirror reflectance are reported. Theoretical simulation is done to numerically optimize for fiber length and output coupler reflectivity to obtain maximum first Stokes power.     

Numerical analysis of stimulated Brillouin scattering in high-power double-clad fiber lasers

A theoretical analysis of stimulated Brillouin scattering (SBS) in linear cavity Yb³⁺-doped double-clad fiber lasers is presented by solving the steady-state rate equations with the SBS. The effects of cavity length, fiber core diameter, input mirror reflectivity at Stokes wavelength, Yb³⁺ concentration and laser linewidth on the SBS are discussed. Numerical results show that the SBS threshold power can be improved by shortening the cavity length, using large mode area fiber, reducing the input mirror reflectivity at Stokes wavelength, lowering the Yb³⁺ concentration and broadening the laser linewidth, and the influence of the laser linewidth on the SBS threshold power is more noticeable than other system parameters.     

Yb3+-doped double-clad fiber laser with all fiber cavity

A novel all fiber cavity Yb3+-doped double-clad fiber laser (DCFL) based on two double-clad fiber (DCF)Bragg grating is presented. The fiber Bragg gratings (FBGs) as the input and output mirrors have been formed in Yb3+-doped DCF with the phase-mask method, and their reflectivities are 99% and 22%,respectively. When the input pump power is 417 mW, the maximum output power is 144 mW with linewidth ＜0.1 nm at the wavelength of 1.057μm, over 40-dB signal-to-noise ratio (SNR), and 50.8% slope efficiency.     

Photonic crystal ber-based multi-wavelength Brillouin ber laser with dual-pass ampli cation con guration

A simple technique for achieving a stable, room temperature and multi-wavelength lasing with narrow linewidth is demonstrated using Brillouin ber laser (BFL) with a 100-m-long photonic crystal ber (PCF) in conjunction with a dual-pass configuration. A broadband ber Bragg grating (FBG) operating in the C-band region is incorporated at the end side of the setup to allow a dual-pass operation. The proposed BFL can operate at any wavelength depending on the Brillouin pump wavelength and the FBG’s reflection region used. With a Brillouin pump (BP) of 15.7 dBm, approximately 7 Stokes and 4 anti-Stokes lines are obtained with a line spacing of 0.08 nm.     

Threshold reduction of stimulated Brillouin scattering in photonic crystal fiber

A simple configuration for the reduction of stimulated Brillouin scattering threshold in photonic crystal fiber is presented. The threshold reduction is contributed by the bidirectional pumping scheme through the reflection of transmitted Brillouin pump back to the gain medium. The pump recycling scheme has greatly reduced the Brillouin threshold of a 200-m long of photonic crystal fiber from 50 to 30 mW of Brillouin pump power.     

Continuous-wave mid-infrared intracavity singly resonant optical parametric oscillator based on periodically poled lithium niobate

This paper reports a continuous-wave (CW) mid-infrared intracavity singly resonant optical parametric oscillator based on periodically poled lithium niobate (PPLN) pumped by a diode-end-pumped CW Nd:YVO$_{4}$ laser. Considering the thermal lens effects, it adopted an optical ballast lens and the near-concentric cavity for better operation. At the PPLN's grating period of 28.5\,$\mu$m and the temperature of 140\du, the maximum idler output power of 155\,mW at 3.86\,$\mu$m has been achieved when the 808\,nm pump power is 8.5\,W, leading to an optical-to-optical conversion efficiency of 1.82{\%}.     

High Power Photonic Crystal Fibre Raman Laser

A cw Raman laser based on a 100-m photonic crystal fibre is demonstrated with up to 3.8 W output power at the incident pump power of 12 W, corresponding to an optical-to-optical efficiency of about 31.6%.. The second order Stokes light, which is firstly reported in a cw photonic crystal fibre Raman laser, is obtained at 1183nm with an output power of 1.6 W and a slope efficiency of about 45.7%.     

Double Brillouin frequency spaced multiwavelength Brillouin-erbium fiber laser with 50 nm tuning range

A 50 nm tuning range multiwavelength Brillouin-erbium fiber laser (MWBEFL) with double Brillouin frequency spacing is presented. Two separated gain blocks with symmetrical architecture, consisted by erbium-doped fiber amplifiers (EDFAs) and Brillouin gain media, are used to generate double Brillouin frequency spacing. The wider tuning range is realized by eliminating the self-lasing cavity modes existing in conventional MWBEFLs because of the absence of the physical mirrors at the ends of the linear cavity. The Brillouin pump (BP) is preamplified by the EDFA before entering the single-mode fiber (SMF), which leads to the reduction of threshold power and the generation enhancement of Brillouin Stokes (BS) signals. Four channels with 0.176 nm spacing are achieved at 2 mW BP power and 280 mW 980 nm pump power which can be tuned from 1525 to 1575 nm.     

Continuous-wave Raman generation in a diode-pumped Nd3+:KGd(WO4)2 laser

Continuous-wave Raman generation in a compact solid-state laser system pumped by a multimode diode laser is demonstrated. The Stokes radiation of stimulated Raman scattering at 1.181 microm is generated as a result of self-frequency conversion of the 1.067 microm laser radiation in Nd3+:KGd(WO4)2 crystal placed in the cavity. The Raman threshold was measured at 1.15 W of laser diode power. The highest output power obtained at the Stokes wavelength was 54 mW. The anomalous delay of Raman generation relative to the start of laser generation (the oscillation buildup) due to slow accumulation of Stokes photons in the cavity at low Raman gain and Raman threshold dependence not only on the laser intensity but also on the time of laser action are observed.     

Achieving single-longitudinal-mode output about Tm:YAG laser at room temperature

We report on the single-longitudinal-mode Tm:YAG laser with a volume Bragg grating pumped by laser diode at room temperature. The maximum SLM power of 142 mW was achieved under incident pump power of 3.22 W. The central wavelength was 2012.6 nm accords with the resonant wavelength of the VBG. Three cavity lengths were used to achieve high efficiency and clear spectrum. The maximum output power were measured to be 450.5, 451.4, and 457.3 mW at incident pump power of 3.22 W, corresponding to a slope efficiency of 17.1, 16.9, and 16.7% for the cavity length of 30, 40, and 50 mm, respectively. 40 mm cavity length having the cleanest spectrum among the three was used for SLM laser with one 1 mm F-P etalon inserted into the cavity.