High-gain quantum-dot semiconductor optical amplifier for 1300 nm

Using an AlGaAs-GaAs waveguide structure with a six-stack InAs-InGaAs "dots-in-a-well" (DWELL) gain region having an aggregate dot density of approximately 8/spl times/10/sup 11/ cm/sup -2/, an optical gain of 18 dB at 1300 nm has been obtained in a 2.4-mm-long amplifier at 100-mA pump current. The optical bandwidth is 50 nm, and the output saturation power is 9 dBm. The dependence of the amplifier parameters on the pump current and the gain recovery dynamics has also been studied.     

High output power 1540 nm vertical cavity semiconductor optical amplifiers

Vertical cavity semiconductor optical amplifiers operating at 1540 nm are presented. The use of AlInGaAs multiple quantum well active regions resulted in record-high saturation output power of +0.5 dBm and 16 dB of fibre-to-fibre gain. These results were achieved in reflection mode operation using optical pumping by a 980 nm semiconductor laser.     

Semiconductor laser amplifier as optical switching gate

The properties of a semiconductor laser amplifier as optical switching gate are investigated. Particular attention is paid to gain, contrast ratio, and switching time of the device. These properties are studied experimentally and theoretically with respect to the injection current, optical input power, and cavity resonances. The experimental arrangements and the theoretical method are described. As an example of the various applications of semiconductor laser amplifier gates, packet switching experiments with self-routing, employing cascaded switching gates, are reported. In a theoretical analysis the restrictions that the properties of semiconductor laser amplifier gates impose on a larger switching system consisting of many such gates are investigated     

High-gain hybrid amplifier consisting of cascaded fluoride-based TDFA and silica-based EDFA in 1458-1540 nm wavelength region

A hybrid optical fibre amplifier is described that consists of a fluoride-based thulium-doped fibre amplifier and a silica-based erbium-doped fibre amplifier connected in a cascade. The amplifier has a gain of more than 25 dB and a noise figure of less than 9 dB over a wide wavelength region of 1458-1540 nm.     

Semiconductor optical amplifier for wavelength conversion in subcarrier multiplexed systems

The fabrication and performance of a InGaAsP-InP semiconductor optical amplifier for wavelength conversion in subcarrier multiplexed system is described. The amplifier is of the buried facet design and has polarization and reflectivity gain ripple of less than 1 dB. Using subcarrier multiplexing, multiple 50-Mb/s data streams at a wavelength of 1.553 /spl mu/m are infected into the amplifier. The gain nonlinearity of the amplifier transfers the data to a different wavelength of light simultaneously injected into the amplifier. Error free retrieval of subcarrier multiplexed data has been demonstrated for the wavelength converted output. The small signal bandwidth of the wavelength conversion process is 5 GHz. Calculation suggests that higher bandwidth is feasible at higher input powers at the expense of lower modulation transfer during wavelength conversion.     

Multi-pump discrete Raman amplifier for CWDM system in the O-band

We demonstrate theoretically that discrete Raman amplifiers operating in the O-band region (1260–1360 nm) are more efficient than in any other band if we consider the fiber attenuation. Compared with the C-band (1530–1565 nm), the net gain is 3 dB higher. We present also theoretically two types of discrete Raman amplifiers which can be used in the O-band with a course wavelength division multiplexing system. The first amplifier has a bandwidth of 70 nm that was designed with four pump lasers operating at 12XY nm. The second one has a bandwidth of 100 nm and needed six pump lasers to obtain a flattened gain across the O-band. In addition, we have analyzed the gain saturation in both optical amplifiers.     

Semiconductor optical amplifier gain anisotropy: confinement factor against material gain

It is shown that different TE/TM mode confinement factors in a bulk semiconductor optical amplifier could not be the main reason for the gain anisotropy. Instead, the intrinsic material gain difference for TE/TM polarised light can well account for this anisotropy and its dependence on pump current.     

Highly nonlinear fiber-based lumped fiber Raman amplifier for CWDM transmission systems

The highly nonlinear fiber (HNLF)-based lumped fiber Raman amplifiers (LRAs) for four- and eight-channel coarse wavelength division multiplexing (CWDM) transmission systems have been investigated. By using the developed LRA, the four-channel CWDM transmission over conventional single-mode fiber (SMF) with the length of 150 km has been successfully achieved.     

采用移频反馈的SOA多波长光纤环形激光器

文章报道了一种基于移频反馈的半导体光放大器(SOA)多波长光纤环形激光器,其环腔内插入声光调制器作为移频器,用自制的光纤马赫-曾德干涉仪进行梳状滤波,在输出光谱1.5 dB带宽为21.7 nm范围内,获得了间隔50 GHz的54个稳定的多波长连续光激射,消光比为28 dB.该激光器具有工作稳定性好、输出光谱宽和不同波长功率平坦度高的优点.实验证明,移频反馈技术能够实现激光器不同起振波长间的增益均衡,使输出光谱带宽增大21.7%.     

All-optical wavelength translation over 80 nm at 2.5 Gb/s usingfour-wave mixing in a semiconductor optical amplifier

Wavelength conversion using conventional single pump four-wave mixing in semiconductor optical amplifiers is limited to wavelength shifts of a few tens of nanometers due to the decrease of signal-to-noise ratio with wavelength shift. In this letter, we demonstrate an 80-mn wavelength shift with four-wave mixing (FWRW) using two orthogonally polarized pumps. The power penalty at a 10^-9 bit-error rate for a 2.5-Gb/s signal is less than 1.0 dB. This result demonstrates the large wavelength shift capacity of this (FWM) technique     

High-gain 1310 nm semiconductor optical amplifier modules with a built-in amplified signal monitor for optical gain control

A compact high-gain 1310-nm semiconductor optical amplifier (SOA) module incorporating two photodiodes to detect radiation emitted from the two opposite facets of the amplifier chip is reported. By subtracting their signals, a measure of the amplified signal is obtained without the need for optical filtering, Using this, amplified signals can be stabilized within 0.5 dB over a 25-dB range of input signals.     

Semiconductor optical amplifier used as an in-line detector withthe signal DC-component conservation

We present in this paper a dc-coupled in-line optical detector based on a multisection semiconductor optical amplifier (SOA). The key principle is to use a voltage reference correlated with the bias voltage level by the way of a two-section or a three-section SOA. So, by means of the differential detection, the signal dc-component is kept with reduced sensitivity to temperature and bias current fluctuations. Experimental and theoretical results are presented when a two-section SOA is used and performance predictions when a three-section is employed. The obtained responsivity is -63 VNV at 40 mA and over -110 VNV at 50 mA when the input optical power, measured within the fiber, is -13 dBm. When the SOA is biased at 40 mA, the detection bandwidth is over 1 GHz when the input optical power is -4 dBm     

非剥脱性Lux1540nm点阵激光治疗黄褐斑的疗效和安全性

目的:观察非剥脱性Lux1540nm点阵激光对黄褐斑的治疗效果和安全性.方法:黄褐斑患者29例,运用Lux1540nm点阵激光(美国Palomar公司生产),波长1540nm,光斑直径15mm,能量6至8J/cm2,每4周一次,6次为一疗程,观察其临床疗效及副作用.结果:29例患者经过治疗后,基本治愈13例(44.8％),显效9例(31％),好转6例(20.7％),无效1例,总有效率为75.9％.治疗后患者的皮肤微红,不出血、不结痂.恢复后无色素脱失,不易产生色素沉着,不产生瘢痕.结论:非剥脱性Lux1540nm点阵激光治疗黄褐斑安全性高,疗效显著,不影响患者的日常生活及工作,是一种安全,有效的方法.     

Semiconductor Raman amplifier for terahertz bandwidth opticalcommunication

Semiconductor Raman amplifiers are useful for frequency selection in terahertz bandwidth and wavelength division multiplexing (WDM) systems with terabit capacity, as well as direct terabit optical communication systems. We have developed GaP-AlGaP Raman waveguides with micrometer-size cross sections. We have reduced residual optical loss of the waveguide by improvement of the fabrication process and realized a low-loss waveguide that is 10-mm long, which has a continuous wave (CW) Raman gain of 3.7 dB. Also, the time-gated amplification with 80-ps pulse pumping is performed and 20-dB gain is obtained. These performances are very suitable for light frequency selection in terahertz bandwidth and WDM optical communication systems     

Dual-wavelength (1050 nm +1550 nm) pumped thulium-doped fiber amplifier characterization by optical frequency-domain reflectometry

We present experimental results of distributed gain measurements from a dual-pumped (1050 nm +1550 nm) thulium-doped fiber amplifier using optical frequency-domain reflectometry. We show that significant reductions in total pump power and/or fiber length are realized with the addition of a few milliwatts at 1550 nm. For our experimental conditions, the addition of 5 mW of 1550 nm allows for a reduction of 100 mW of pump power at 1050 nm or a reduction of 44% of doped fiber length to reach the same gain as with 1050-nm pumping alone.     

基于SOA的L波段多波长锁模光纤环形激光器

报道了一种基于半导体光放大器(SOA)的L波段多波长光纤环形激光器,采用自制的100GHz信道间隔的光纤Mach-Zehnder(M-Z)干涉仪作为梳状滤波器,电吸收调制器(EAM)实现主动锁模,在1593.6nm附近获得了11个波长的同步锁模脉冲序列,脉冲重复频率为10GHz,半高全宽约为24ps,不同波长间功率不平坦度小于1dB。激光器具有工作稳定、输出光谱较宽和不同波长间功率波动小的特性。     

Internal optical loss measurements in InGaAs-InAlGaAs quantum-well lasers operating around 1550 nm

A multisection device technique is employed to carry out internal optical loss measurements in two types of InGaAs-InAlGaAs quantum-well structures. One structure consists of conventional identical-width quantum wells and the other, a broader spectral-width material, consists of multiple-width quantum wells in the active region. The temperature dependence of the internal optical losses is also investigated for both structures.     

Erbium-doped fiber amplifier pumped in the 950-1000 nm region

The pump wavelength dependence of the gain of an erbium-doped fiber amplifier pumped in the wavelength region 950-1000 nm is discussed. It is found that efficient gain at 1.557 μm, between 25 and 28 dB for 17 mW of launched pump power, can be obtained for any wavelength pump in the range 965-985 nm. The optimum length of erbium fiber needed is found to vary as a function of pump wavelength. The gain as a function of signal wavelength is also investigated at these pump wavelengths     

Actively gain-flattened erbium-doped fiber amplifier over 35 nm byusing all-fiber acoustooptic tunable filters

We demonstrate an actively gain-flattened erbium-doped fiber amplifier (EDFA) using an all-fiber gain-flattening filter with electronically controllable spectral profiles. A good gain flatness (<0.7 dB) over a broad wavelength span (>35 nm) is achieved for a wide range of operational gain levels as well as input signal and pump powers