Wavelength-switchable La-codoped bismuth-based erbium-doped fiber ring laser

A wavelength-switchable La-codoped bismuth-based erbium-doped fiber ring laser with the capability to switch to one of 35 lasing wavelengths, spaced at 0.8 nm from 1545 to 1575 nm, is reported. Excellent wavelength stability of better than 1 pm and power fluctuation of less than 0.15 dB were observed during a 2-h stability test.     

Wavelength-switchable single-frequency erbium-doped fiber ring laser

We demonstrate a single-frequency and wavelength-switchable fiber ring laser obtained by a Lyot filter used in combination with a sampled fiber Bragg grating and a saturable absorber. The operating wavelength of the laser can be tuned, with a constant 0.8-nm step, in the range 1552.6-1555.8 nm. The tuning mechanism works on the rotation of the polarization of Lyot filter input signal. The structure of the laser is very simple regarding its characteristics: an output power of 6 dBm, with a signal-to-noise ratio higher than 60 dB and a spectral linewidth of 8 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     

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.     

A self-seeded tunable multiwavelength erbium-doped fiber ring laser with fiber bending scheme

A new tunable multiwavelength fiber laser is proposed. Such a laser contains a homogeneous and inhomogeneous broadening media, i.e., a Fabry–Perót laser diode and an erbium-doped fiber amplifier, in the laser cavity. The Fabry–Perót laser diode is used to obtain tunable multiwavelength lasing. By adjusting the injection current of the Fabry–Perót laser diode, emission at a single wavelength, dual wavelengths, triple wavelengths or quadruple wavelengths are obtained. The lasing wavelength is tuned by bending a section of fiber in the laser cavity. The tuning ranges for single wavelength lasing and dual wavelength lasing are 20 nm and 10 nm, respectively, while those for triple wavelength lasing and quadruple wavelength lasing are 7 nm and 3 nm, respectively.     

单环掺铒光纤激光器光延迟反馈的混沌控制

为了找到更加简单稳定激光系统的混沌化方法,采用光延迟反馈方法对单环掺铒光纤激光器特性进行了数值仿真,得到了各种周期现象而且产生了混沌现象。结果表明,利用单模单环掺铒光纤激光器,在附加光延迟反馈环路的方法下可以实现混沌控制。这一结果对应用于保密通信的混沌化简化具有重要意义。     

Switchable multiwavelength erbium-doped fiber ring laser with a multisection high-birefringence fiber loop mirror

We proposed and demonstrated a new concept of switchable multiwavelength erbium-doped fiber ring laser with a multisection high-birefringence fiber loop mirror (HiBi-FLM). The HiBi-FLM results in the laser operating on different allowed wavelengths. The wavelength switching can be achieved by modifying the reflection spectrum of HiBi-FLM through two polarization controllers. The experiment demonstrates the switchable lasing operation within the random combination of three wavelengths, as well as with a large (/spl sim/40 dB) output signal to background noise ratio.     

150-nm tuning range in a grating-coupled external cavityquantum-dot laser

An antireflection (AR) coated single-stack quantum-dot (QD) laser in a grating-coupled external cavity is shown to operate across a tuning range from 1.095 μm to 1.245 μm. This 150-nm range extends from the energy levels of the ground state to excited states. At any wavelength, the threshold current density is no greater than 1.1 kA/cm ². This large tunable range is the product of the rapid carrier filling of the higher energy states under a low pumping current and homogeneous broadening in the QD ensemble. The possibility of a larger tuning range is discussed with the further improvement of the AR-coating     

A widely tunable narrow-linewidth triple-wavelength erbium-doped fiber ring laser

A widely tunable narrow-linewidth simultaneous triple-wavelength oscillation erbium-doped fiber ring laser (EDFRL) is investigated in detail. The EDFRL can produce double-wavelength oscillations with the same polarization output, as well as another widely tunable wavelength oscillation with orthogonal polarization in both the C-band and the L-band. By preventing two polarization-mode competitions, we have achieved a stable single-longitudinal-mode triple-wavelength lasing output along with a minimum side-mode suppression ratio of 40 dB.     

Broad-band injection seeding of an erbium-doped fiber ring laser

We present a broad-band (40 MHz) injection-seeded erbium-doped fiber ring laser with a low finesse cavity. Broad-band operation is achieved by seeding an arbitrary number of longitudinal modes in this cavity. This fiber laser is advantageous because it has the potential to substantially suppress stimulated Brillouin scattering for lidar applications.     

Multiwavelength erbium-doped fiber laser with 0.8-nm spacing using sampled Bragg grating and photonic crystal fiber

We propose and demonstrate a novel room-temperature multiwavelength erbium-doped fiber laser (EDFL) with a 0.8-nm wavelength spacing based on four-wave mixing (FWM) in a length of high-nonlinear photonic crystal fiber and sampled-fiber Bragg grating. The FWM processes suppress the wavelength competition of the EDFL and increase the number of lasing wavelength. By adjusting the FWM efficiency, the number of the concurrent lasing wavelengths can be changed, and the peak power differences among the main oscillation wavelengths are less than 2.0 dB.     

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     

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.     

Sampled grating tunable twin-guide laser diodes with over 40-nm electronic tuning range

Device and tuning characteristics of sampled grating tunable twin-guide laser diodes are presented. The vertically integrated, monolithic widely tunable laser requires only two tuning currents to fully cover a wavelength range of more than 40 nm by electrooptic tuning. Its tuning behavior is quasi-continuous with up to 8.2-nm broad continuous tuning regions. High sidemode suppression (SMSR /spl ges/ 35 dB) as well as large output power (P /spl ges/ 10 mW) are obtained over the wavelength range from 1520.5 to 1561.5 nm.     

Wavelength-switchable erbium-doped fiber ring laser using spectral polarization-dependent loss element

We propose a wavelength-switchable erbium-doped fiber ring laser that uses a spectral polarization-dependent loss element. The element was fabricated by inscribing a long-period grating on a polarization-maintaining fiber. Dual-wavelength switching operation was accomplished by rotating the polarization plane of the fiber laser cavity. The amplitude variation of both laser lines was measured to be less than 1 dB and the signal-to-amplified spontaneous emission ratio was more than /spl sim/40 dB.     

Multiwavelength erbium-doped fiber ring laser incorporating an SOA-based phase Modulator

A novel room-temperature multiwavelength erbium-doped fiber (EDF) laser is demonstrated. Stable multiwavelength lasing at room temperature is realized by incorporating a semiconductor optical amplifier (SOA)-based phase modulator in the laser cavity. The SOA is biased below the transparent point with a sinusoidal signal applied to achieve phase modulation, to suppress the homogenous line broadening of the EDF. Stable multiwavelength lasing with wavelengths up to 26 and wavelength spacing as small as 0.19 nm is demonstrated at room temperature.     

Mode-locked erbium-doped fiber ring laser using intracavity polarization-maintaining loop mirror

Erbium-doped fiber lasers at repetition rate of 40 and 80 GHz are demonstrated in an injection-locked and rational harmonic mode-locked ring cavity. The cavity has a polarization-maintaining loop mirror. The injection-locking pulse is generated at repetition rates of 20 and 40 GHz from another rational harmonic mode-locked fiber laser. When these pulses are injected into the second fiber laser, pulses at twice the repetition rates viz. 40 and 80 GHz are produced.     

宽带铋基掺铒光纤放大器的增益箝制研究

应用于动态通信网络中的光放大器需要恒定的信号增益.为此,设计了一个基于环形激光腔结构的宽带铋基掺铒光纤放大器(Bi-EDFA),进行了宽带Bi-EDFA信号增益箝制特性的理论研究.结果表明:通过将放大器输出的一个前向放大自发辐射(ASE)噪声光反馈到输入端,可以实现对1.53 μm波段传输信号的增益箝制.环路损耗越小,...     

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     

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