Wavelength-switchable fiber ring laser using cascaded fiber Bragg gratings combined with amplitude modulator

The wavelength-switchable fiber laser has been studied in this paper. A wavelength-switchable erbium-doped fiber ring laser constructed using cascaded five fiber Bragg gratings (FBGs) incorporated with amplitude modulator is achieved and switching over 5 separate wavelengths has been demonstrated. The output power is about −4 dB m, the 3-dB linewidth is less than 0.02 nm, and the side mode suppression ratio is more than 45 dB. The transit process of the wavelength switching from one wavelength to another is studied and the lasing competition is also investigated.     

A Stabilized and Tunable Single-Frequency Erbium-Doped Fiber Ring Laser Employing External Injection Locking

A stabilized and tunable single-longitudinal-mode erbium-doped fiber ring laser has been proposed and experimentally demonstrated. The laser is structured by combining the compound cavity with a fiber Fabry-Peacuterot tunable filter. An injection-locking technique has been used to stabilize the wavelength and output power of the laser. One of the longitudinal modes is stimulated by the injected continuous wave so that this mode is able to win the competition to stabilize the system. A minimum output power of 0.6 dBm and a signal-to-noise ratio of over 43 dB within the tuning range of 1527-1562 nm can be achieved with the proposed technique. A wavelength variation of less than 0.01 nm, a power fluctuation of less than 0.02 dB, and a short-term linewidth of about 1.4 kHz have also been obtained     

注入锁定掺铒光纤环形腔激光器及波长调谐技术

研究了掺铒光纤环形腔激光器(EDFRL)的注入锁定现象,提出了一种实现可调谐的单纵模EDFRL波长及功率稳定的新方法,即利用注入锁定技术向法布里-珀罗可调滤波器结合复合腔结构的EDFRL腔内注入低功率的连续光,使某一纵模在注入连续光的基础上起振.这个纵模在对增益介质的竞争中可以稳定地占据优势,从而与注入信号发生锁定,实现激光器输出光谱的稳定.实验得到激光器在1527.4～1561.9 nm范围内波长可调,输出功率＞0.6 dBm,信噪比(SNR)＞43 dB;输出光波长与功率抖动分别＜0.01 nm和≤0.02 dB,且线宽约为1.4 kHz.     

平坦功率输出的宽带波长可调光纤环型激光器

为了获得一种平坦功率输出的宽带波长可调的掺铒光纤环型激光器，提出采用一高双折射光纤环镜获得其平坦功率输出，在高双折射光纤环镜中，采用了大量的高双折射光纤段和偏振控制器，它们的反射光谱可补偿掺铒光纤环型激光器输出功率光谱的不平坦，通过压缩或者延伸激光腔里的分布式光纤布喇格光栅即可实现波长调谐。实验验证可以获得一种宽达38nm的宽带波长调谐(1527nm～1565nm)，输出功率的不平坦被控制在±0．8dB范围之内，总输出功率大约4dBm、3dB线宽为0．01nm、旁瓣抑制比为48dB的光纤环型激光器。     

一种高性能环形可调谐光纤光栅激光器研究

研制了一种新型的高性能环形可调谐光纤光栅激光器。该激光器使用980nm LD作为泵浦源,使用长度为10. 8m的新型增益平坦掺铒光纤作为增益介质,采用可调谐光纤光栅滤波器进行波长调谐,调谐范围可达41nm (1528nm～1569nm) ,中心波长可精确调谐到C波段指定的ITU - T标准中心波长处, 3dB 带宽< 0. 08nm, 25dB带宽< 0. 2nm,波长稳定性优于0. 01nm,边模抑制比> 60dB。最大输出功率46. 94mW,功率稳定性优于±0. 02dB,阈值泵浦功率7. 3mW,斜率效率为39. 75%。并分析了不同腔长、不同输出耦合比对输出功率的影响。     

环行腔掺铒光纤激光器调谐实验研究

本文自行设计环行腔可调谐光纤激光器,研究环行腔掺饵光纤激光器的调谐技术,采用应力可调谐光栅进行实验,解决了光纤激光器普遍存在的泵浦光反射形成的回波影响问题和窄线宽激光输出功率与激光模式的矛盾,讨论了输出耦合比对调谐特性的影响,实现了窄带滤波和宽带调谐的双重特性,实现了窄线宽可调谐激光输出。     

Tunable Fiber Laser Using a Broad-Band Fiber Mirror and a Tunable FBG as Laser-Cavity Ends

By using a broad-band fiber mirror (BFM) and a tunable fiber-Bragg-grating at either end of laser cavity, a wavelength tunable erbium-doped fiber laser is demonstrated. In a forward pump scheme using 100 mW pump power at 1480 nm, stable lasing output power of 21.14-mW measured at 1544.8 nm is obtained with a threshold pump power of 4.7 mW. A side-mode suppression ratio as high as 57.9 dB, wavelength tuning range up to 30 nm with step resolution of 0.2 nm and power variation less than plusmn1.0 dB are achieved. For a backward pump scheme, the BFM acts as a broad-band reflector both for the lasing signal and pump source. The high performance, cost-effective BFM based tunable fiber laser may play an important role in fiber optics communication and fiber sensing applications.     

基于Hi-Bi FLM的离散式L带可调谐掺铒光纤激光器

研究了利用高双折射光纤环形镜（HiBiFLM）结合L带可调谐的波长选择薄膜滤波器,以掺Er^3＋光纤为增益介质,以0．8nm波长间隔计,可获得L波段41个离散可调谐波长的可调谐输出,各信道波长输出功率变化的最大幅度小于3．1dB,光信噪比（OSNR）优于32dB。     

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。     

Widely tunable S-band fiber-ring lasers and broadband amplified spontaneous emission sources with thulium-doped fluoride fibers

This paper reports our investigation on widely tunable fiber-ring lasers and broadband amplified spontaneous emission (ASE) light sources with thulium-doped fluoride fibers (TDFs). The experimental results for thulium-doped optical fiber amplifiers will also be discussed. We achieved widely tunable fiber lasers that had tuning ranges of 94 nm with 1550 nm + 1050 nm pump configurations and of 85 nm with 1550 nm + 1400 nm pump configurations, respectively. It was observed that the lasers oscillated under multilongitudinal-mode operation with linewidth of 400 MHz, signal-to-source noise ratio of 60 dB, and power stability of 0.003 dB for a laser output of 1 mW. A broadband ASE source with a power density of more than -15 dBm/nm between 1465 and 1535 nm was also demonstrated with a novel hybrid configuration by using both TDF and erbium-doped fiber.     

A tunable S-band erbium-doped fiber ring laser

In this paper, we experimentally investigate and demonstrate an S-band erbium-doped fiber (EDF) ring laser based on an erbium-doped silica fiber and 980-nm pumping laser. Widely tunable range from 1480 to 1522 nm, and the sidemode suppression ratio (SMSR) of >30 dB/0.1 nm and the output power of >-2 dBm in the operating range from 1482 nm to 1517 nm have been achieved for this ring laser. Under the constant power control, the output power variation less than /spl plusmn/0.05 dB can also be accomplished over the tuning range from 1482 to 1517 nm. This S-band EDF ring laser is promising for the future S-band applications.     

基于啁啾莫尔光栅的可调波长掺饵光纤环腔激光器

A simple and cost-effective wavelength-switchable fiber ring laser based on a chirped moire fiber grating (CMFG)and an erbium-doped fiber amplifier (EDFA) is proposed,and stable wavelength Iasing oscillations at room temperature iS experimentally demonstrated.To serve as a wavelength selective element,the CMFG possesses excellent comb-like filtering characteristics including stable wavelength interval and ultra-narrow passband.and its fabrication method iS easy and flexible.The measured optical signal-to-noise ratio reaches the highest value of 50 dB and the power fluctuation of each channel output iS less than 0.5 dB within an hour.The output laser power of different channels is almost identical(difference of less than 1 dB) within the tunable range.Methods to optimize the laser performance are also discussed and the superiority of the CMFG iS experimentally demonstrated.     

掺铥光纤激光器波长可调谐输出特性

利用1 550 nm光纤激光器搭建了一个同带泵浦环形腔掺铥光纤激光器,并对其光谱输出特性进行了研究。在1 550 nm激光泵浦下,1.6 m掺铥光纤自发辐射谱覆盖1 800~1 900 nm范围,3 dB带宽大于60 nm;通过在腔内插入隔离器,获得了线宽小于0.2 nm的激光输出,中心波长在1900 nm附近;进一步在腔内加入FP腔,获得了可调谐的窄线宽输出,光谱调谐范围达60 nm,覆盖从1 840~1 900 nm的光谱范围,激光线宽仅为0.07 nm。另外,在腔内使用通信波段用FP腔,同样获得了较宽调谐范围的窄线宽输出。输出光谱分为1 820~1 850 nm和1 865~1 915 nm两个区域,调谐范围共达80 nm。结合使用2 000 nm FP腔的可调谐光谱范围,该激光器在1 820~1 915 nm的范围都可以获得激光输出,与掺铥光线的自发辐射谱基本相符。     

A stabilized and tunable erbium-doped fiber ring laser with double optical filter

We have proposed and experimentally demonstrated a stabilized and tunable erbium-doped fiber ring laser by using a Fabry-Pe/spl acute/rot laser and a fiber Fabry-Pe/spl acute/rot filter. The sidemode suppression ratio of >30 dB/0.1 nm and the output power of >2.2 dBm can be achieved while this ring laser is tuned from 1528.28 to 1559.64 nm with the step of 1.12 nm. The wavelength variation of less than 0.01 nm and the power fluctuation of /spl les/0.04 dB have also been obtained. When the constant output power is controlled by adjusting the bias current of 980-nm pump laser, the power variation of less than /spl plusmn/0.05 dB can be obtained over the entire tunable range.     

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。     

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。     

基于马赫-曾德尔干涉仪的可调谐掺镱光纤激光器

A ring-shaped all fiber tunable Yb-doped fiber laser with tuning range over 20 nm is demonstrated by using a fiber Mach-Zenhder interferometer as an intra-cavity filter which is constructed with two 3-dB optical couplers. The method for fabricating the fiber Mach-Zenhder interferometer is detailed. The fiber laser has a moderate milli-Watt level output power over the whole tuning range from 1050 to 1071 nm, a side-band suppression ratio greater than 45 dB, and a bandwidth less than 0.1 nm.     

Tunable microwave photonic filter based on a fiber ring and erbium-doped fiber amplifier

The tunable microwave photonic filter based on a fiber ring and erbium-doped fiber amplifier （EDFA） was proposed. By introducing a section of erbium-doped fiber （EDF） into the fiber ring, the loss of the signal can be compensated by the EDFA gain through adjusting the pump power. This can largely increase the number of the effective sampling taps, and then improve the performance of the microwave photonic filter notably. When the pump power was set to be 42.7 roW, a microwave bandpass filter with the 3-dB bandwidth of 0.15 MHz, the Q factor up to 100 and extinction ratio up to 20 dB was achieved. By employing a tunable optical delay line in the above fiber ring, a tunable microwave photonic filter has been realized through tuning the length of the optical delay line. The proposed tunable microwave photonic filter can fred great applications in microwave signal processing and ROF system.     

A 1.7 Gb/s ASK and a 622 Mb/s incoherent FSK transmissionexperiment using a 1.55-μm multiquantum well distributed feedbacklaser

A multiple-quantum-well distributed-feedback (MQW-DFB) laser with narrow linewidth and low frequency chirp at low output power may experience linewidth rebroadening at high output power. the rebroadening is mostly due to a large carrier-induced change of refractive index, which also causes a large frequency modulation response for the MQW-DFB lasers. Using a 1.55-μm MQW-DFB laser, a 622-Mb/s amplitude-shift-keying (ASK) transmission experiment employing 200-km of fiber and an erbium-doped fiber amplifier has been demonstrated having a dispersion power penalty less than 9.8 dB. The receiver sensitivities at BER=10^-9 of the ASK system are -34.5 dBm and -42.5 dBm for 1.7-Gb/s and 622-Mb/s modulation, respectively. A 622-Mb/s incoherent frequency-shift-keying (FSK) transmission experiment using the same laser has also achieved a receiver sensitivity of -42.5 dBm     

Highly optimized tunable Er3+-doped single longitudinalmode fiber ring laser, experiment and model

A continuous wave (CW) tunable diode-pumped Er³⁺-doped fiber ring laser, pumped by diode laser at wavelengths around 1480 nm, is discussed. Wavelength tuning range of 42 nm, maximum slope efficiency of 48% and output power of 14.4 mW have been achieved. Single longitudinal mode lasing with a linewidth of 6 kHz has been measured. A fast model of erbium-doped fiber laser was developed and used to optimize output parameters of the laser