Optical bistability in a traveling-wave SOA connected to a DFB laser diode: theory and experiment

We investigate the bistable response of a traveling-wave semiconductor optical amplifier (SOA) connected bidirectionally to a distributed feedback (DFB) laser diode. By contrast to dispersive DFB amplifiers, bistability is possible for a broad wavelength range of the injected optical signal. A theoretical analysis clarifies the origin of the phenomenon and the conditions under which it occurs. Numerical simulations and experimental results confirm the theoretical analysis. Experimentally obtained step heights up to 25 dB and widths of the bistability domain of 1-4 dB have been found.     

Nonlinear gain in vertical-cavity semiconductor optical amplifiers

We report on the wavelength-dependent nonlinear-gain properties of a vertical-cavity semiconductor optical amplifier. A step-like output versus input transfer curve and bistability are found on the long wavelength side of the resonant peak. The characteristics are caused by a dispersive nonlinearity arising from gain saturation in the device. The nonlinear transfer of the amplifier could be used for logic regeneration and all-optical logic operations, while the optical injection power required to switch the device is an order of magnitude lower than previously reported with edge-emitting devices.     

Closed loop spectral control of multiwavelength 1550 laser

The spectral flatness of multiwavelength emission from an InGaAsP semiconductor optical amplifier based ring laser is controlled by a programmable liquid crystal spatial light modulator based on spectrally monitoring the individual wavelength intensities of the laser output. Spectrally equal amplified output is also shown by predistorting the laser to account for amplifier spectral gain dependence     

Broad-band all-optical flip-flop based on optical bistability in an integrated SOA/DFB-SOA

We have demonstrated a broad-band all-optical flip-flop for wavelength-division-multiplexing system based on optical bistability in a semiconductor optical amplifier (SOA)/distributed feedback (DFB)-SOA with wide gain bandwidth for both SOA and DFB-SOA regions. Input signal with two different wavelength selections of 1530.45 and 1578.12 nm and the repetition ration of about 6 ns is injected into the SOA/DFB-SOA.     

Optical spectral bistability in a semiconductor fiber ring laserthrough gain saturation in an SOA

We demonstrate the operation of optical bistability in a widely tunable semiconductor fiber ring laser, using a semiconductor optical amplifier (SOA). The laser can be operated in two bistable states: the spectrum of the first state has one main lasing peak with very narrow linewidth, and the second state has simultaneous oscillation of two main peaks at different wavelengths. The two bistable states can be switched to each other using either electrical or optical methods. We further explain the bistable operation using the theory of two-mode competition through gain saturation in the SOA     

A 10-Gb/s Monolithically Integrated Filterless InGaAsP/InP Widely Tunable Wavelength Converter With Conversion Gain

In this paper, we present the details of a monolithically integrated filterless wavelength converter based on photocurrent-driven technology. The device consists of an integrated tunable laser transmitter and an optical receiver. The transmitter includes a sampled-grating distributed-Bragg-reflector laser, an electroabsorption modulator, and a semiconductor optical amplifier. The optical receiver employs two semiconductor optical amplifiers and a quantum-well p-i-n photodetector. The wavelength converter is characterized at 10 Gb/s over a variety of bias conditions at various input-power levels in various digital-system experiments. Bit-error-rate measurements at 10 Gb/s over an output tuning range of 32 nm between 1531 and 1563 nm show power penalties less than 1 dB. Similar experiments over an input wavelength range of 25 nm from 1535 to 1560 nm show a power penalty less than 2.5 dB. For a wavelength conversion from 1548 nm to a range of output wavelengths between 1531 and 1563 nm, the facet-to-facet gain ranges from 9 to 13 dB, neglecting fiber coupling losses.     

单片集成倾斜SOA的宽可调谐取样光栅分布布拉格反射激光器

高功率和宽调谐范围的单片集成倾斜SOA的宽可调谐取样光栅分布布拉格反射激光器被成功制备。倾斜的SOA结构和端面增透膜有效的降低了端面的反射率。器件调谐范围大于38nm,波长覆盖较好,调谐范围内波长输出功率均大于9mW。     

Monolithic integration of widely tunable sampled grating DBR laser with tilted semiconductor optical amplifier

High output powers and wide range tuning have been achieved in a sampled grating distributed Bragg reflector laser with an integrated semiconductor optical amplifier. Tilted amplifier and anti-reflection facet coating are used to suppress reflection. We have demonstrated sampled grating DBR laser with a tuning range over 38 nm, good wavelength coverage and peak output powers of more than 9 mW for all wavelengths.     

基于两只半导体光放大器级联结构的多波长光纤激光器

通过数值模拟对两只半导体光放大器(SOA)级联结构的静态增益饱和特性进行了理论研究.在不考虑自发辐射的情况下,分析了注入电流对两只SOA级联结构增益的影响.实验上构建了一种基于两只SOA级联结构的多波长光纤激光器,观测并分析了半导体光放大器的驱动电流和增益带宽对多波长输出结果的影响.在室温下,获得了基本符合ITU-T标准100 GHz的27个波长以上的稳定多波长输出,各信道输出功率不平坦度小于±3 dB,线宽小于0.102 nm,信噪比大于25 dB,总输出功率为1.94 mW,并且与由单只SOA构成的多波长光纤激光器进行了对比.     

A 980-nm band laser diode pump source with a detuned wavelength of1000 nm for praseodymium-doped fiber amplifiers

By using practical high-power 980-nm band laser diodes, efficient direct pumping for a praseodymium-doped fiber amplifier (PDFA) is achieved. The lasing wavelength is detuned from 980 to 1000 nm by selective optical feedback from a fiber grating     

Ultrashort Pulse Amplification at 1080 nm With a Long-Wavelength InGaAs–GaAs Flared Amplifier

Pulses of 5 ps in duration have been amplified using a long-wavelength InGaAs-GaAs semiconductor optical amplifier containing a flared waveguide. The amplifier is seeded using short pulses emitted by a passively mode-locked semiconductor laser. Average output powers of 50 mW have been obtained at a center wavelength of 1080 nm for a drive current of 290 mA. Pulse compression yields durations as short as 520 fs and peak powers as high as 40 W. Perspectives for combining the semiconductor master oscillator power amplifier with Yb fiber amplifiers in a hybrid configuration are also briefly discussed.     

All-optical phase modulation in a traveling wave semiconductorlaser amplifier

A novel all-optical phase modulation and wavelength conversion has been demonstrated in a traveling wave semiconductor laser amplifier. Even though the optical gain modulation caused by the saturation effect in a traveling wave semiconductor laser amplifier is sensitive to the signal wavelength, the optically controlled phase modulation is relatively independent of the signal wavelength     

一种基于反射式SOA的FBG传感解调方法

提出一种基于反射式半导体光放大器（R-SOA）的光纤Bragg光栅（FBG）传感解调方法。周期性调谐R-SOA与可调谐FBG构成的窄带可调谐激光器,当其输出波长与FBG传感器反射波长一致时,由光电探测器输出光电流最大判断2个FBG周期的匹配并完成对传感FBG周期的测量。测量结果表明,FBG传感器中心波长在1 551.9...     

Thermal optical bistability in InGaAs/InAlAs MQW etalons at 1.5 mu m wavelength

The authors report on the fabrication of devices assembled in one unit and the observation of thermal optical bistability with low threshold and high reproducibility using the low-energy side of a 1.54- mu m etalon peak. The devices are InGaAs/InAlAs multi-quantum-well (MQW) nonlinear etalons, whose finesse of 20 was obtained by using a SiO/sub 2//TiO/sub 2/ high-reflectivity coating. The authors also show that the nonlinear characteristics depend on the wavelength of the incident light detuned from the etalon peak. The relation between optical bistable characteristics and incident beam wavelength is studied in detail using a tunable F-center laser.<>     

1.3-μm Pr-doped In-Ga-based fluoride fiber amplifiers pumped bygrating-fiber-pigtailed 0.98-μm-band laser diodes with a detunedwavelength of 1 μm

At most efficient pump wavelength, a praseodymium-doped In-Ga-based fluoride fiber is directly pumped by four 0.98-μm-band laser diodes. These lasing wavelengths are detuned from 0.98 to 1 μm by external selective optical feedback from fiber grating reflectors. Maximum signal output power of +13.5 dBm is obtained at 1.296 μm. Four-wavelength multiplexed signals at 1.296-1.311 μm are amplified with a deviation of gain less than 1.9 dB. By using the amplifier as a power booster, data of 2.5 Gb/s is successfully transmitted more than 100 km     

Harmonically mode-locked fiber laser with optically selectablewavelength

In this letter, we demonstrate optical selection of wavelength in a harmonically mode-locked fiber laser that incorporates a semiconductor optical amplifier nonlinear fiber loop. Wavelength tuning is achieved by controlling the delay time between the modulation and the control signals in the compensated dispersion-tuning scheme. A tuning range over 19 nm is obtained. The power suppression of nonlasing modes reaches a maximum of 34 dB. The output wavelength and the delay time are governed by a linear relationship     

Noise and error rate performance of semiconductor laser amplifiers in PCM-IM optical transmission systems

Applications of semiconductor laser amplifiers in intensity modulated digital optical transmission systems were studied theoretically. An optical linear amplifier repeater between electronically regenerating terminal repeaters and an optical linear preamplifier in front of a photodetector in an electronically regenerating repeater are discussed. Both traveling-wave type and Fabry-Perot cavity type laser amplifiers are considered. The noise and error rate performance in these systems are evaluated using formulations for semiconductor laser amplifiers. The mean and variance in the optical amplifier output photons calculated by the photon master equation [1] is used to obtain the worst case variance in the equalized output voltage [2] for these systems. The required receiving power reduction from direct detection scheme by a preamplifier system and the repeater spacing expansion between two electronically regenerating terminals by an optical linear amplifier repeater system are delineated.     

Precise and rapid wavelength-switching of fibre laser usingsemiconductor optical amplifier

A simple fibre laser scheme for fast and accurate wavelength switching is demonstrated, with a semiconductor optical amplifier being used as the gain medium. The laser cavity is composed of a Fabry-Perot semiconductor filter (FPSF) and a set of narrowband fibre Bragg gratings (FBGs), which determine the wavelength references. The FPSF can be tuned by changing its injection current to select a particular wavelength from those of the FBGs, and a wide tuning range can be achieved based on the Vernier effect. During switching between two discrete wavelengths, a build-up time as short as several microseconds was obtained. Furthermore, because of the short upper-state lifetime of a semiconductor amplifier, relaxation oscillations caused by wavelength switching were eliminated     

Small signal analysis of optical FM signal amplification by aninjection-locked type semiconductor laser amplifier

A small-signal analysis for optical FM signal amplification by an injection-locked type semiconductor laser amplifier with consideration of the spurious intensity modulation (SIM) is presented. In general, the performance of optical FM signal amplification by a laser amplifier is affected by the value of the injection power, by the performance of the injecting laser (the master laser), and by the difference between the emission frequencies of the master and slave optical cavities. In particular, when the modulation frequency is very low, the output frequency deviation (FD) of the laser amplifier turns out to coincide with that of the master laser. However, SIM of the laser amplifier in this case is influenced by the injection conditions. A suitable definition, the ratio of the output FD to SIM to the input FD to SIM, is given to evaluate the performance of an injection-locked-type semiconductor laser amplifier     

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