Stimulated Brillouin Scattering in a Single-Mode Tellurite Fiber for Amplification, Lasing, and Slow Light Generation

In this paper, Brillouin gain performances of tellurite fiber are investigated for photonics applications. We demonstrate stimulated Brillouin amplification and lasing and the simulated performance of slow light generation in a single-mode tellurite fiber. A Brillouin gain of 29 dB is achieved in a 100-m tellurite fiber with a pump power of 10 mW at 1550 nm. A peak value of Brillouin gain coefficients of 1.6989 X 10^-10 m/W is measured on the base of gain characteristics. An all-fiber Brillouin laser with the maximum unsaturated power of 54.6 mW at 1550 nm and a slope efficiency of 38.2% is achieved from a 200-m tellurite fiber by employing a ring cavity. Furthermore, widely tunable (~27 nm) Brillouin comb laser with 26 lines spaced at 7.97 GHz is obtained from the ring laser cavity including an erbium-doped fiber amplifier (EDFA). A simple theoretical model based on laser threshold theory successfully explains the properties of Brillouin comb lasers. Stimulated Brillouin scattering (SBS)-induced time delay per unit power and per unit length is also calculated using the measured data of Brillouin gain coefficients. A peak value of 0.09246 ns/mW/m and a time delay slope efficiency of 1.75 ns/dB are obtained for this tellurite fiber. Potential performance of a tellurite fiber for slow light generation is clarified on the base of Brillouin gain characteristic. Our results show that tellurite fiber is a promising gain medium for Brillouin fiber amplifiers, lasers, and slow light generation due to its low background loss and large Brillouin gain coefficient.     

一种线形腔的多波长布里渊掺铒光纤激光器

布里渊掺铒光纤激光器(BEFL)是一种利用非线性效应——布里渊散射来实现多波长输出的激光器,波长间隔大约为0.088 nm(11 GHz).研究了一种多波长布里渊掺铒光纤激光器线形结构,通过引入反馈实现多波长输出.在布里渊泵浦功率为11 mW,980 nm泵浦功率为12 mW时获得了波长间隔为0.08 nm的34个波长的激光输出以及1 525～1 570 nm可调谐范围.并通过调节980 nm抽运光功率以及布里渊泵浦光波长,实现了可调谐的多波长输出.还研究了980 nm抽运光功率对产生的斯托克斯光波数的影响.     

A stable optical comb with double-Brillouin-frequency spacing assisted by multiple four-wave mixing processes

A stable optical comb with a double-Brillouin-frequency spacing, employing a 2.5-km common single mode fiber (SMF) is proposed and demonstrated experimentally. The simultaneous existence of the first-order and third-order Stokes within the ring cavity excites the higher-order Stokes and anti-Stokes via multiple four-wave mixing (FWM) processes. Ten odd-order Stokes, nine odd-order anti-Stokes and a second-order Stokes signal with a wavelength spacing of 0.172 nm (∼20 GHz) are simultaneously achieved at a Brillouin pump (BP) level of 160 mW. The maximum power fluctuation of the proposed optical comb is less than 1 dB at room temperature within 100 min. The optical comb can show a good stability and flexibility in the choice of operating wavelength.     

超短环形腔布里渊掺铒光纤激光器

提出了一种超短环形腔布里渊掺铒光纤激光器(BEFL),腔长仅为10m。该BEFL以4m长的普通掺铒光纤(EDF)为激光增益介质,腔外布里渊抽运光和980nm抽运光的注入在掺铒光纤中,分别引入非线性布里渊增益和线性掺铒光纤放大器(EDFA)增益。实验结果表明,BEFL工作在单纵模状态,输出信噪比高(>40dB),抽运阈值低(～20mW),输出功率大(>10mW),且布里渊抽运光不仅决定BEFL的输出波长,更对其抽运阈值和出光功率有重要影响。     

Linewidth narrowing in semiconductor laser pumped all-fibre Brillouin ring laser

Brillouin lasing in an all-fibre ring resonator made of polarisation-maintaining fibre using a semiconductor laser pump at 830 nm is reported. The stimulated Brillouin scattering (SBS) lasing threshold is 0.91 mW, and the Stokes output is polarised and exhibits linewidth narrowing.<>     

Tunable and narrow linewidth multi-wavelength Brill- ouin-erbium fiber laser using dual-wavelength pumping

We demonstrate a multi-wavelength Brillouin-erbium fiber laser (BEFL) with narrow linewidth and tunable wavelength interval using dual-wavelength Brillouin pumping. The generation of multi-wavelength output in BEFL is based on the combination of stimulated Brillouin scattering (SBS) and four-wave mixing (FWM) effect in a fiber cavity. The tunable wavelength interval is determined by the artificially controlled wavelength interval of the pumping lasers. The BEFL could compress a 1 MHz pump laser to a 340 Hz Brillouin Stokes laser, which proves the BEFL has excellent capability of linewidth compression. An erbium-doped fiber pumped by 980 nm laser is inserted into the cavity to further amplify the Brillouin laser. The wideband multi-wavelength BEFL covering over 50 nm is successfully generated when the 980 nm pump power is 400 mW. These features of multi-wavelength BEFL provide an effective method for optical communication systems and optical fiber sensing.     

波长间隔为20 GHz的多波长布里渊光纤激光器

设计了一种基于环形腔的双倍布里渊频移间隔的可调谐光纤激光器实验装置。 该实验装置由一个3 dB耦合器、一台可调谐激光源(TLS)、一台980 nm泵浦和一个实现双倍布里渊频移环形腔构成。该结构耦合输出偶数阶Stokes光,从而实现间隔约为20 GHz或0.16 nm的多波长输出。并研究了980 nm泵浦光和BP光功率对输出偶数阶Stokes光波数的影响。当980 nm 泵浦功率固定为26 dBm(400 mW),BP功率为10 dBm时,获得了间隔为0.16 nm的11个稳定激光输出以及36 nm(1530~1566 nm)的可调谐范围。     

间隔双倍频移的可调谐多波长布里渊/铒光纤激光器

设计了一种结构简单的波长间隔双倍布里渊频移的可调谐多波长布里渊/铒光纤激光器。利用一个3 dB耦合器形成复合环形腔结构,使奇数阶斯托克斯信号被局限在一个腔内循环,仅有初始布里渊抽运信号和偶数阶的斯托克斯信号能够耦合输出,实现了波长间隔双倍布里渊频移的多波长输出。分析了不同布里渊抽运功率、不同980 nm抽运功率下激光器的输出特性。在布里渊抽运信号功率10 dBm,980 nm抽运功率110 mW的情况下,激光器在1555~1565 nm范围内获得了波长间隔0.176 nm的6个波长输出。     

Broadband diode-pumped fibre laser

Reports the observation of a strong dependence of the emission spectrum (centre wavelength and linewidth) of Nd:silica fibre lasers on pump wavelength. In a particular fibre, careful selection of the pump wavelength has led to the operation of a broadband fibre laser at 1060 nm with 19 nm FWHM bandwidth. When pumped with a 30 mW diode laser, it exhibits a 1 mW threshold, a 2.5 mW output, and an intrinsic average wavelength temperature stability of about 10 p.p.m./°C     

Brillouin fibre laser with 20 m-long photonic crystal fibre

Brillouin fibre laser is demonstrated using a very short length of photonic crystal fibre (PCF). A simple ring resonator is used in the experiment which consists of a 20 m long highly nonlinear PCF and 49 cm long Bismuth-based erbium-doped fibre (Bi-EDF). The proposed Brillouin laser is able to generate up to 3 Stokes and 3 anti- Stokes lines in the 1560 nm region at a channel spacing of 0.09 nm.     

Highly efficient Er-doped fibre amplifiers pumped in 660 nm band

High gain coefficient in an erbium-doped fibre amplifier, 3.8 dB/mW at 1.536 mu m and 2.3 dB/mW at 1.552 mu m, is achieved for a pump wavelength of 664 nm by using an erbium-doped fibre with a high numerical aperture of 0.285 and thermally-diffused expanded core fibre ends. The gain at 1.536 mu m reaches 30 and 35 dB for launched pump powers of 10 and 15 mW, respectively.<>     

增益型受激布里渊相移谱宽范围功率特性

相移谱的功率依赖特性对矢量布里渊光时域分析系统的优化设计具有重要意义。对增益型受激布里渊散射（SBS）相移谱进行了建模分析；搭建了外差pump-Stokes系统，在5~90 mW泵浦光功率和5 W~9 mW斯托克斯光功率范围内测量了400 m标准单模光纤的增益型SBS相移谱；分析了Stokes光功率影响增益型SBS相移的机理。结果表明:当固定Stokes光功率时，增益型SBS相移范围与泵浦光功率成良好线性关系；因泵浦耗尽作用的影响，导致当Stokes光功率由5 W上升至8 mW时，增益型SBS相移范围的泵浦光功率灵敏度由1.448（）/mW下降至1.156（）/mW。根据理论和实验结果，对增益型VBOTDA系统进行了优化设计分析，为其在长距离和高精度传感领域的发展奠定了基础。     

Multiwavelength L-Band Brillouin–Erbium Comb Fiber Laser Utilizing Nonlinear Amplifying Loop Mirror

In this paper, we demonstrate a novel multiwavelength L-band Brillouin-erbium fiber laser utilizing nonlinear amplifying loop mirror. The erbium-doped fiber section in the fiber loop mirror provides efficient amplification of Brillouin pump (BP) to generate the stimulated Brillouin scattering in the single-mode fiber coil. The laser structure can achieve symmetry breaking of the loop without requirements to an asymmetric coupler or polarization controller. The proposed fiber laser has a low threshold power of about 10 mW to create the first Brillouin-Stokes signal. The maximum number of 27 Stokes signals with a spacing of 0.089 nm is achieved by setting the BP wavelength at 1604 nm and its BP power is set at 2.2 mW.     

基于受激布里渊散射的可调谐多波长激光器

可调谐多波长布里渊掺铒光纤激光器将光纤中的SBS非线性放大同掺铒光纤的线性放大相结合得到室温稳定的多波长输出,具有波长间隔一致、线宽窄、功率谱相对平坦等优点。设计了一种基于光纤布拉格(FBG)反射的线性可调谐多波长布里渊掺铒光纤激光器。该线性腔激光器的一端利用光纤布拉格光栅作为反射镜,有效抑制了腔内自激模的影响,增加激光器输出波长数。布里渊泵浦信号进入布里渊增益介质之前经过掺铒光纤放大器的两次放大,降低了布里渊增益的阈值。该多波长激光器实现了1 530～1 560 nm之间30 nm可调谐范围的输出。在布里渊泵浦信号功率2 mW,980 nm泵源抽运功率60 mW情况下,1 540～1 554 nm范围内,获得了波长间隔0.088 nm的16个波长的输出。     

Efficient operation of an Yb-sensitised Er fibre laser pumped in0.8 μm region

The dependence of threshold and slope efficiency on pump wavelength around 0.8 μm has been investigated for an Yb-sensitised fibre laser. Results confirm a wider choice of pump wavelength compared with unsensitised Er fibre. A 5 mW threshold and slope efficiency of 8.5% were observed for 820-830 nm pumping     

基于MOPA结构的1064nm单频光纤激光器

为了抑制受激布里渊散射效应, 提高单频窄线宽种子源的放大功率, 采用主振荡功率放大器结构, 并对光纤长度、纤芯直径和抽运参量进行优化, 实现了42W的1064nm信号光输出。实验中, 一级放大采用914nm半导体激光器作为抽运源, 增益光纤芯径10μm, 长度8m;二级放大采用976nm半导体激光器作为抽运源, 增益光纤芯径20μm, 长度2.4m。在种子光功率40mW、一级放大的抽运功率6.8W、二级放大的抽运功率85W时, 得到了42W的1064nm信号光输出。结果表明, 光光转换效率约49.4%, 偏振消光比27.5dB; 输出信号光中心波长1064.5nm, 线宽约70MHz, 保持了种子光的单频特性。在42W连续输出时没有观察到受激布里渊散射, 继续增大抽运功率, 有望实现更高功率的放大。     

Efficient upconversion pumping at 1.064 mu m Tm/sup 3+/-doped fluoride fibre laser operating around 1.47 mu m

1.064 mu m upconversion pumping was used to operate a highly efficient CW and Q-switched thulium (Tm/sup 3+/)-doped fluoride fibre laser at around 1.47 mu m. The maximum CW output power was 100 mW for a launched pump power of 570 mW. The threshold power was 200 mW, the slope efficiency 27% and the wavelength width 20 nm. A peak power of 70 W was generated for Q-switching at a launched pump power of 300 mW.<>     

宽带可调谐双频移多波长布里渊光纤激光器

提出了一种采用高非线性光纤作为布里渊增益介质 的双倍布里渊频移间隔的多波长布里渊光纤激光器(MW-BEFL)。激光器利用两个环形器构成 双倍频移结构,将奇数阶的斯托克斯信号隔离在腔内循环,仅有泵浦 信号和偶数阶的斯托克斯信号能够耦合输出,实现了双倍布里渊频移的多波长输出。激光器 腔内没有引入 任何的有源增益介质对斯托克斯信号进行放大,消除了腔内自激模的影响。激光器的调谐范 围由布里渊泵 浦的工作波长和掺铒光纤放大器(EDFA)的增益带宽决定。实验中,在布里渊 抽运 功率为0dBm、EDFA的输出功率为20 dBm的情况下,在1536~1605nm之间得到双频移间隔的多 波长输出,调谐范围是69nm。     

Slow light generation in singlemode er-doped tellurite fibre

The efficient generation of slow light in a singlemode Er-doped tellurite glass fibre, which has a Brillouin gain coefficient about an order of magnitude larger than silica fibre is reported. Pulses of 60 ns width were delayed by 67 ns in a 2 m length of fibre with a pump power of 630 mW. The large Brillouin gain and relatively low loss of tellurite fibre should be useful in the realisation of compact slow light devices operable at a lower pump power.     

Highly stable low-noise Brillouin fiber laser with ultranarrow spectral linewidth

We demonstrate an all-fiber high-power single-frequency Brillouin fiber ring laser with maximum power of 100 mW at 1.55 /spl mu/m, which is actively stabilized by using the Pound-Drever-Hall frequency-locking scheme. Significant reduction (/spl sim/20dB) of both relative intensity noise and frequency noise was observed in the Brillouin Stokes radiation as compared with those noises of its pump source, a narrow-linewidth Er-doped fiber laser. Ultranarrow spectral linewidth of the Brillouin fiber lasers was investigated by both delayed self-heterodyne technique and heterodyne beat technique between two independent Brillouin fiber lasers.