Widely tunable narrow linewidth erbium doped fibre ring laser

An erbium doped fibre ring laser enabling singlemode operation over a continuous wavelength tuning range of 44 nm (1528 nm-1572 nm) with laser linewidths of less than 10 kHz is reported.<>     

Electrooptic tuning of a fiber ring semiconductor laser

This letter reports recent results obtained in the area of wavelength tuning of semiconductor lasers. The laser is constructed from an InGaAsP 1300-nm semiconductor optical travelling-wave amplifier. The cavity consists of a fiber ring resonator using a low fiber coupler as the output mirror. The intra-cavity electrooptic tuner works as a one-stage Lyot filter and allows wavelength tuning over a spectral range of 20 nm with a tuning rate of 0.05 nm V^-1. This is one of the best results reported using electrooptic birefringent tuning systems     

Wide continuous wavelength tuning of a narrow linewidth DBR laser

A continuous wavelength tuning range of 5.4 nm is obtained for a three-section DBR (distributed Bragg reflector) laser by applying one control current in both forward and reverse bias directions. In the reverse direction no significant linewidth broadening is seen due to the absence of injection-recombination shot noise, and a linewidth of less than 3 MHz is obtained over a wavelength span of 1.8 nm. The minimum linewidth observed is 580 kHZ     

A widely tunable narrow linewidth semiconductor fiber ring laser

We have demonstrated a novel approach to obtain a 0.1-nm line width laser with 38-dB sidemode suppression by utilizing a 1.3-μm semiconductor optical amplifier in a fiber unidirectional ring that consists of a linear polarizer and polarization controllers. The laser has a low-threshold current of 22.5 mA as well as a wide tuning range of 28 nm. The new approach is applicable to the 1.55-μm region as well. It is expected that nanosecond wavelength tuning speed is feasible using this approach in conjunction with fast electrooptic polarization controllers, short cavities and low-cavity losses     

Travelling-wave erbium fibre ring laser with 60 kHz linewidth

Operation of an erbium-doped-phospho-alumino-silicate-fibre ring laser in a unidirectional travelling-wave configuration enables narrow linewidth, single frequency emission to be obtained at a wavelength of 1.555 mu m. A 60 kHz linewidth has been measured.<>     

Narrow linewidth operation of an erbium fiber laser containing achirped Bragg grating etalon

A numerical model is presented which shows that a control signal suitable for preventing longitudinal mode hops can be derived by sensing changes in the polarization state of the light reflected from an intracavity etalon. This is verified experimentally by including a continuous fiber etalon formed from chirped Bragg reflectors in a unidirectional erbium ring fiber laser. Mode hop free operation is observed with resolution limited linewidths of 170 kHz     

Optimization of wavelength tuning of erbium-doped fiber ring lasers

The dynamics of erbium-doped fiber ring lasers undergoing wavelength tuning is examined. The relaxation oscillations and mode build-up time are characterized. An all-optical damping technique which is capable of complete elimination of relaxation oscillations is analyzed, and measurements on a tunable erbium-doped fiber lasers are reported. An analytical solution is derived for the mode build-up time of tunable fiber lasers. Limiting parameters for the design of a high-speed tunable fiber laser are identified. An equalization technique for obtaining uniform switching speed is described     

光纤激光器波长调谐技术研究

介绍了可调谐掺铒光纤激光器的工作原理和几种可调谐滤波器的工作特性及其调谐技术方法,重点介绍了光纤光栅作为滤波器的特性及其反射波长调谐技术.概述了掺铒光纤激光器输出波长调谐技术的现状,分析了有待解决的技术问题.     

High efficient and narrow linewidth fiber laser based on fiber grating Fabry-Perot cavity

A high Er3+-doped narrow linewidth fiber laser based on fiber Bragg grating Fabry-Perot cavity was demonstrated. The spatial hole burning effect was restrained by a fiber Faraday rotator. Two short fiber Bragg grating Fabry-Perot cavities as narrow bandwidth filters discriminated and selected laser longitudinal modes efficiently. A stable single-frequency 1534.83 nm laser was acquired. Pumped by two 976 nm laser diodes and two-ended output, the fiber laser exhibited a 12 mW threshold. Total 39.5 mW output power and one end 22 mW output power were obtained at the maximum 145 mW pump power. Optical-optical efficiency was 27% and slope efficiency was 29.7%. The output power seemed to be saturated when pump power increased. The 3 dB linewidth of the laser was less than 7.5 kHz, measured by the delayed self-heterodyne method with 15 km monomode fiber. The high power narrow linewidth fiber laser can be used in high resolution fiber sensor systems.     

Rapid continuous tuning of a single-polarization fiber ring laser

We have developed and studied what we believe is the first fiber laser operating in a single polarization at 1550 nm with PM fiber output and capable of wavelength tuning over a 20-nm bandwidth in less than 50 μs. The fast wavelength tuning speed in a fiber laser is achieved by incorporating an acousto-optic tunable filter into the laser. The same filter is used in an optoelectronic feedback loop to suppress the relaxation oscillations induced by wavelength transitions     

基于萨格纳克环与光栅的双波长光纤激光器

报道一种基于保偏光纤的萨格纳克环与级联的光纤布拉格光栅的双波长掺铒光纤激光器,该激光器采用简单的线性腔结构,所用的萨格纳克环担当了梳状滤波器,光栅组构成了波长选择器件;在偏振烧孔的作用下,通过调整偏振控制器,激光器能够输出5种不同的激发模式,其中,双波长2种,单波长3种;所有的激发线具有小于0.3nm线宽,大于24dB的光学信噪比;同时,该激光器展示了较好的波长与峰值功率稳定性.     

Widely tunable wavelength spacing dual-wavelength single longitudinal mode erbium doped fiber laser

A simple widely tunable wavelength spacing dual-wavelength single longitudinal mode (SLM) erbium doped fiber laser (EDFL) based on cascaded fiber Bragg gratings (FBGs) and birefringent fiber filter is proposed and demonstrated. Experimental results show that the lasing wavelength spacing is widely tunable in a range from 2 nm to 18 nm, which has potential to generate frequency tunable terahertz (THz) waves by beating the lasing dual-wavelength in a high speed photodetector. The birefringent fiber filter acts as an ultra-narrow bandpass filter and benefits the simultaneous oscillation of dual-wavelength in a single laser cavity. The output peak power of the lasing dual-wavelength is approximately equalized at room temperature, and a high optical signal-to-noise ratio (OSNR) is realized in the whole tuning range. The SLM operation of dual-wavelength fiber laser is verified by Fabry–Perot (F–P) scanning interferometer, and the clear eye diagram proves that the proposed fiber laser is effective in the application of fiber optic communication system.     

Soliton fiber ring laser stabilization and tuning with a broadintracavity filter

The periodic perturbations to the soliton in passively mode-locked fiber soliton lasers cause dispersive wave shedding, which lead to sharp spectral sidebands that limit pulse duration. By using a broad intracavity birefringent plate filter, the side-bands are greatly reduced, and the pulse duration is shortened. The filter also allows wavelength tuning, and a 43 nm continuous tuning range is demonstrated for pulses of 311-357 is duration in a fully self-starting diode pumped system     

Correlation of relative intensity noise with linewidth floors in narrow linewidth DFB lasers

The relative intensity noise of narrow linewidth DFB lasers in the vicinity of linewidth floors is measured. A strong correlation between linewidth rebroadening and a corresponding increase in the relative intensity noise for frequencies below 3 GHz is observed for devices with mode suppression ratios in excess of 35 dB.<>     

A 40-GHz 850-fs regeneratively FM mode-lockedpolarization-maintaining erbium fiber ring laser

An 850-fs pulse train at 40 GHz was directly generated from a regeneratively FM mode-locked fiber laser. The soliton effect was used to generate a short pulse and to suppress the supermode noise. The laser was locked to an external signal by a phase-locked loop (PLL) technique and the wavelength was tunable between 1540 and 1555 mn     

La-codoped bismuth-based erbium-doped fiber ring laser with 106-nm tuning range

Ultrawide-band tunable fiber ring lasers using 84.6-cm-long lanthanum-codoped bismuth-based erbium doped fiber and a narrow-band tunable microelectromechanical system filter are reported. The fiber ring lasers can be continuously tuned from 1520 to 1626 nm, covering both the C- and L-bands. The laser has two outputs; the high output power port exhibits better than 35-dB wavelength extinction ratio, and the second output has much lower power but exhibits a large extinction ratio of better than 60 dB.     

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。     

Multiple wavelength operation of an erbium-doped fiber laser

Wavelength-locked, six-channel, colasing operation using a single gain medium is reported for the first time. The system is an all-fiber, erbium-amplifier-based design that uses a grating wavelength division multiplexer with a fixed channel spacing of 4.8 nm for frequency selection. The authors investigate two possible configurations for the laser cavity     

IPG光纤激光发生器外部调制器调制激光强度和脉宽的实现

本文简述了IPG对调制信号的要求和下位机的工作原理,介绍了外部调制器调制激光强度和脉宽的实现过程。     

Characterization of the chirp and intensity modulation propertiesof an SOA-MZI wavelength converter

Wavelength converters based on cross-phase modulation in semiconductor optical amplifiers (SOAs) in the arms of a Mach-Zehnder interferometer (MZI) provide a key network element for reconfigurable optical networks that incorporate wavelength routing. For system design purposes, the properties of the intensity and phase (chirp) modulation of the wavelength-converted signal for an SOA-MZI wavelength converter are important. In this paper, the small-signal α parameter, which characterizes the converter chirp, and the conversion frequency response are characterized experimentally for an integrated all-active SOA-MZI wavelength converter. For both co- and counterpropagating signals, the variation of the a parameter along the interference and conversion curves is considered in detail. Three optical modulators with quite different chirp properties are used to generate the modulated input signal to the wavelength converter. The results demonstrate that the chirp of the wavelength-converted signal is primarily determined by the device properties and the intensity of the modulated input signal. The a parameter of the wavelength-converted signal is negative for noninverting operation and positive for inverting operation. An important contribution of the paper is the detailed assessment of this key device characteristic. The experimental characterization of the wavelength converter is incorporated into a device model that can be used to obtain the pulse response. Calculated and measured results for the time dependence of the intensity and chirp of the wavelength-converted signal are in good agreement. The conversion frequency response for the intensity modulation is also measured along the conversion curve. The 3-dB bandwidth is found to be generally about 8-10 GHz