Electrooptic narrow linewidth wavelength tuning and intensity modulation of an erbium fiber ring laser

We report an electrically tunable fiber laser featuring a 50-channel wavelength switching capability with a 0.2 nm linewidth and -20 dB crosstalk. The laser consists of an Er-doped fiber resonator and an electro-optic TE-TM convertor used as a wavelength tunable filter. It allows wavelength tuning over a spectral range of 10 nm with a tuning rate of 0.05 nm/V and a linewidth of 0.06 nm.     

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     

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     

光纤光栅外腔半导体激光器波长调谐方法研究

可调谐光纤光栅外腔半导体激光器（FBG-ECL）激射波长由光纤光栅布喇格波长决定,调谐光纤光栅布喇格波长可以改变激光器的激射波长.重点介绍采用轴向应力、径向应力和温度对光纤光栅布喇格波长的调谐.布喇格中心波长的偏移与轴向应力、径向应力和温度等变化量均呈极好的线性比例关系,且在较大的测量范围内一直保持线性关系.详细说明了光纤光栅外腔半导体激光器采用这三种方法调谐时的特点、适用范围,并对它们的性能进行了比较,给出在不同条件下适合的调谐方法.     

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     

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.     

Frequency tuning and pulse generation in a fiber laser with anintracavity semiconductor active filter

The authors demonstrate optical frequency tuning by direct electrical means as well as FM and AM mode-locking in an erbium-doped fiber laser with an intracavity distributed Bragg reflector active filter/modulator. They obtained a 6 nm discrete tuning range and pulses of 38 and 78 ps duration in AM and FM mode-locking, respectively     

Electrical tuning of semiconductor interferometric laser

A semiconductor laser with a Michelson interferometer type cavity was electrically tuned by pumping each of its two branches separately. Two tuning modes were observed, small continuous tuning over 2.5 to 3 ? and step tuning with a total shift of 34 ?.     

Wavelength tuning of a semiconductor laser using nematic liquidcrystals

The authors report a single frequency, extended cavity laser diode operating at 1500 nm wavelength and using an intracavity liquid cell wavelength filter to tune the wavelength over 6 nm by mode hopping. Continuous tuning over the free spectra range of the cavity is also demonstrated     

Theoretical analysis of tunable wavelength conversion based on FWM in a semiconductor fiber ring laser

A comprehensive broad-band dynamic model of a tunable wavelength converter based on four-wave mixing (FWM) in a semiconductor fiber ring laser (SFRL) is presented. Critical factors, e.g., the material gain profile, the longitudinal variation of the optical field, the carrier density, photon density, and the broad-band spontaneous noise emission, are considered in the model. Therefore, the static and dynamic characteristics of this kind of wavelength converter can be predicted more accurately. By numerical simulation, the effects of the input signal power, injection current, the coupling coefficient of the output coupler, and the lasing wavelength on the conversion efficiency of the wavelength converter are investigated. Also, the optical pulse pattern, frequency chirp, and extinction ratio of the conjugate signal are evaluated. To widen the dynamic range of input signal power, an erbium-doped fiber amplifier (EDFA) is added into the SFRL. The characteristics of this tunable wavelength converter with an SFRL are investigated in detail.     

NOLM-NALM fiber ring laser

We study the bidirectional lightwave propagations in an erbium-doped fiber ring laser and an inverted-S fiber ring laser, and observe their optical bistability behaviors. We develop a model for the inverted-S fiber ring laser using nonlinear optical loop mirror and nonlinear amplifying loop mirror (NOLM-NALM) principle, which operates in the nonlinear region. Good agreements between the laser experimental performance and the developed model are achieved. The laser shows good switching and pulse compression capabilities. In addition, the laser model illustrates the route to chaotic operation via period doubling bifurcation, when the input power increases. We also obtain quasi-periodic operation when the laser is amplitude modulated experimentally.     

Electric tuning of semiconductor laser using acousto-optic device

An electrically tunable semiconductor laser system is given using an acousto-optic (AO) device and a commercially available semiconductor laser. Rapid scanning of laser oscillation frequency is obtained using frequency modulation of the driving RF power for the AO device. Also, simultaneous two-frequency oscillation is realised using two RF power sources.<>     

基于半导体光放大器和取样光纤光栅结合Sagnac环的多波长光纤激光器

Multi-wavelength fiber ring laser based on the semiconductor optical amplifier(SOA)with sampled fiber Bragg grating(SFBG)in a Sagnac loop interferometer as the wavelength-selective filter is proposed.Four lasing wavelengths with 1.8 nm spacing have been generated stably at room temperature.The proposed laser has the advan-tages such as removal of the high-cost circulator,flexibility in channel-spacing tuning,and simple all-optical fiber configuration,which has potential applications in high-capacity wavelength-division-multiplexed(WDM)systems and mechanical sensors.     

外腔半导体激光器宽带调谐特性

本文分析了强反馈外腔半导体激光器的宽带频率调谐特性,得到了最大频率调谐范围公式,利用1.5μm外腔半导体激光器实现了1.45μm至1.57μm范围内的波长宽带调谐(120nm调谐范围)。     

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     

Single-longitudinal-mode multiwavelength fiber ring laser

A single-longitudinal-mode multiwavelength fiber ring laser is proposed and demonstrated. The single-longitudinal-mode operation is realized using a fiber loop mirror with a saturable absorber. The fiber loop mirror acts as a passive self-tracking narrow multiband optical filter. Single-longitudinal-mode multiwavelength lasing is generated by using either a Lyot-Sagnac filter or a fiber grating array.     

Injection-seeded Q-switched fiber ring laser

We present a narrow linewidth, injection-seeded Q-switched Er fiber ring oscillator, that provides over 600 /spl mu/W of average output power at 500 Hz, with 1.2 /spl mu/J per pulse, before the output appears to be significantly affected by stimulated Brillouin scattering. This laser configuration provides multiple advantages in LIDAR systems because it offers the possibility of broad and rapid tunability.     

A fiber Raman ring laser

A fiber Raman ring laser was synchronously pumped by a cavity-dumped argon laser. The Raman laser was tuned with either a piezoelectric intracavity interferometer or by varying the pump pulse rate.     

Postgrowth tuning of semiconductor vertical cavities formultiple-wavelength laser arrays

Combined lateral-vertical oxidation of AlGaAs is investigated as a means of tuning the resonant wavelength of a semiconductor microcavity after the epitaxial growth. It is shown that this technique can provide arrays with a wavelength spread equal to the cavity's free spectral range with a single postgrowth processing step. Design issues for multiple-wavelength vertical-cavity laser arrays using this postgrowth tuning technique are discussed, comparing the performance of devices with all-semiconductor and partially or totally oxidized Bragg mirrors. Experimental results are presented on arrays with a 48-nm lasing span around 970 nm, using partially and totally oxidized mirrors     

Frequency pulling in a Brillouin fiber ring laser

The lasing frequencies of a Brillouin fiber ring laser are shifted slightly from the resonant frequencies of the cold fiber ring resonator due to the optical Kerr effect and the nonlinear phase shift associated with stimulated Brillouin scattering (SBS) used as the gain mechanism in this type of laser. These frequency pulling effects are investigated in detail both theoretically and experimentally. The results of this study are useful in many Brillouin fiber ring laser applications such as Brillouin fiber optic gyroscopes, microwave generators, and frequency shifters. To the authors' knowledge this is the first time the frequency pulling effect caused by the nonlinear phase shift associated with SBS is reported