1.3-μm vertical-cavity amplifier

We demonstrate the first 1.3-μm vertical-cavity optical amplifier. The amplifier was optically pumped and operated in reflection mode. Optimization of the top mirror reflectivity resulted in a 9.4-dB continuous wave fiber-to-fiber gain, a gain-bandwidth product of 220 GHz, and a saturation output power of -6.1 dBm, all at room temperature. By modulating the pump source, an extinction ratio of 27 dB in the output signal power was obtained     

Acceleration of gain recovery in semiconductor optical amplifiersby optical injection near transparency wavelength

By using optical injection near the transparency wavelength of semiconductor optical amplifiers, we show experimentally that both the saturation output power and the gain recovery can be greatly improved. By injecting 80 mW of pump power, we observe a 3-dB increase in saturation output power. For 73 mW of pump power, we find a reduction in gain recovery time from over 200 ps down to below 40 ps, while maintaining 14 dB of fiber-to-fiber gain at 1555-nm wavelength     

High-temperature characteristics and tunability of long-wavelength vertical-cavity semiconductor optical amplifiers

In this study, we investigate the high-temperature characteristics and the temperature tuning of long-wavelength vertical-cavity semiconductor optical amplifiers (VCSOA). The temperature shift of the peak-signal gain is shown to depend on the mirror reflectivity of the VCSOA. Experimental results of temperature tuning of a 1.3-/spl mu/m VCSOA are presented. We demonstrate 10 dB of fiber-to-fiber gain over a tuning range of approximately 8 nm.     

Design and analysis of vertical-cavity semiconductor opticalamplifiers

The authors present detailed, yet largely analytical, models for gain, optical bandwidth, and saturation power of vertical-cavity semiconductor optical amplifiers (VCSOAs) in reflection and transmission mode. Simple formulas for the gain-bandwidth product are derived. The saturation model considers a sublinear material gain, gain enhancement by the standing-wave effect, and all relevant carrier recombination mechanisms. Excellent agreement with measurements on novel 1.3-μm VCSOAs is obtained. The models are used to analyze device performance and to investigate optimization options. Parameter plots are given which allow for an easy exploration of the VCSOA design space, matching desired performance data with the required mirror reflectivity and pump current     

Long-wavelength monolithic GaInNAs vertical-cavity optical amplifiers

We report on the continuous-wave amplification characteristics of an optically pumped 1.3-/spl mu/m multiple-quantum-well GaInNAs-GaAs vertical-cavity semiconductor optical amplifier (VCSOA). The VCSOA structure was monolithically grown by molecular beam epitaxy and operated in reflection mode in a fiber-coupled system. The maximum on-chip gain attained, limited by the onset of laser action, was 15.6 dB at 196 mW of 980-nm pump power. For a chip gain of 10.4 dB, the optical bandwidth was 10.8 GHz and the saturation output power was -9 dBm. By varying the pump laser power, a maximum extinction ratio of 22.3 dB was obtained. Temperature-controlled tuneable operation of the device is also presented and demonstration of 9 dB of chip gain obtained over 9.5 nm with an optical bandwidth of 12 GHz is reported.     

A fiber connectorized MEMS variable optical attenuator

A voltage-controlled moving-mirror microelectro-mechanical systems variable optical attenuator is described that has less than 1-dB fiber-to-fiber insertion loss at 1550-nm wavelength and greater than 50-dB dynamic range. The device was configured with a simple feedback circuit to operate as an optical power regulator capable of stabilizing the output power to within 0.26 dB for a 12-dB input power excursion     

MEMS-tunable vertical-cavity SOAs

We present the signal gain, wavelength tuning characteristics, saturation properties, and noise figure (NF) of MEMS-based widely tunable vertical-cavity semiconductor optical amplifiers (VCSOAs) for various optical cavity designs, and we compare the theoretical results to data generated from a number of experimental devices. Using general Fabry-Pe/spl acute/rot relationships, it is possible to model both the wavelength tuning characteristics and the peak signal gain of tunable vertical-cavity amplifiers, while a rate-equation analysis is used to describe the saturation output power and NF as a function of the VCSOA resonant wavelength. Additionally, the basic design principles for an integrated electrostatic actuator are outlined. It is found that MEMS-tunable VCSOAs follow many of the same design trends as fixed-wavelength devices. However, with tunable devices, the effects of varying mirror reflectance and varying single-pass gain associated with the MEMS-based tuning mechanism lead to changing amplifier properties over the wavelength span of the device.     

Amplified spontaneous emission and gain characteristics ofFabry-Perot and traveling wave type semiconductor laser amplifiers

Semiconductor laser amplifiers are investigated with respect to amplified spontaneous emission power and gain characteristics. The influence of the spontaneous emission coefficient, input power, and facet reflectivity on amplifier saturation characteristics is analyzed. It is shown that a small β, zero reflectance device has advantageous properties in terms of high gain and output power at the 3-dB compression point. The low reflectance contributes to a slow saturation, whereas a low β means a larger optical model and hence lower intensities and less saturation for a given output power or gain     

垂直腔半导体光放大器的增益特性数值分析

结合垂直腔半导体光放大器(VCSOAs) 的竖直微型腔结构带来的特性,在反射工作模 式情况下,分析了VCSOAs 的增益特性。通过数值求解激光器单模速率方程,给出了增益、饱和输出功率随泵浦光功率、出射腔面反射率的变化,分析了其功率动态范围。得出了提高腔面反射率能使增益得到增长,以及强泵浦光功率能起到平坦增益,增大增益的作用的结论。总结了VCSOAs 设计中的一些规律,以作实际应用中参考。     

Performance comparison of GaInNAs vertical-cavity semiconductor optical amplifiers

This paper reports on theoretical and experimental investigations of the influence of the number of GaInNAs quantum wells (QWs) on performance of 1.3-/spl mu/m vertical-cavity semiconductor optical amplifiers (VCSOAs). Full characterization is carried out for two optically pumped VCSOAs with 6 and 15 QWs in the active layer. The 15-QW amplifier is found to be more efficient for amplification purposes but the highest gain to date was obtained for a 6-QW GaInNAs VCSOA, 19-dB on-chip gain in single-mode operation, having a top mirror reflectivity of 97.7%. At high-gain and for low enough reflectivity, the intrinsic noise figure is smaller than 5 dB.     

Fabrication and characterization of 1 550 nm polarization-insensitive semiconductor optical amplifiers

Semiconductor Optical Amplifiers (SOAs) can beused asin-line amplifier ,preamplifier ,optical switch,andwavelength converter in future optical systems[1-3].Po-larization-independent gain,high output power and lowgain ripple are desirable features for most…     

VCSOA动态开关特性的理论研究

区别于常规的法布里-珀罗（F—P）腔增益公式,本文结合传输矩阵和载流子速率方程从理论上研究了垂直腔半导体光放大器（VCSOA）的动态开关特性。模拟结果发现,VCSOA作为光开关应用时,可以达到ns级的开关延时和15dB以上的消光比;在满足增益需求的前提下减小顶部分布布拉格反射镜（DBR）的膜层周期,以及正确设置关状态下的抽运电流密度值略高于增益截止区水平,是同时得到较好的开关延时和输出消光比的重要因素。     

Vertical-cavity amplifying modulator at 1.3 μm

The modulation/switching properties of a vertical-cavity semiconductor optical amplifier operating at 1.3 μm wavelength are investigated. The device was optically pumped and operated in reflection mode. A 150-mV (100 mA) modulation of the drive to the pump source produced a 7-dB modulation of the pump power, which produced a 35-dB modulation in the output signal. The maximum extinction ratio was 35 dB, and limited by device heating. Frequency response measurements revealed a modulation bandwidth of 1.8 GHz when the amplifier was saturated. This enabled 2.5-Gb/s modulation of a -10 dBm input signal with 5.5-dB fiber-to-fiber gain     

Over 15 dB gain from a monolithically integrated optical switchwith an amplifier

An optical switch is monolithically integrated with a semiconductor optical amplifier on a InP substrate. The switch is of the total internal reflection type. The device has achieved 15-dB chip gain at 1530-nm wavelength and fiber-to-fiber lossless transmission over a wavelength range of 80 nm. Crosstalk attenuation varies from 13 to 6 dB. This device demonstrates the feasibility of lossless integrated optics on InP. The technology applied allows monolithic integration of various active components with a minimum of extra technology steps     

Modeling reflective bistability in vertical-cavity semiconductor optical amplifiers

The characteristics of optical bistability in a vertical-cavity semiconductor optical amplifier (VCSOA) operated in reflection are reported. The dependences of the optical bistability in VCSOAs on the initial phase detuning and on the applied bias current are analyzed. The optical bistability is also studied for different numbers of superimposed periods in the top distributed bragg reflector (DBR) that conform the internal cavity of the device. The appearance of the X-bistable and the clockwise bistable loops is predicted theoretically in a VCSOA operated in reflection for the first time, to the best of our knowledge. Moreover, it is also predicted that the control of the VCSOA's top reflectivity by the addition of new superimposed periods in its top DBR reduces by one order of magnitude the input power needed for the assessment of the X- and the clockwise bistable loop, compared to that required in in-plane semiconductor optical amplifiers. These results, added to the ease of fabricating two-dimensional arrays of this kind of device could be useful for the development of new optical logic or optical signal regeneration devices.     

Angled-Facet Spot-Size-Converter Integrated Semiconductor Optical Amplifiers Using Asymmetric Twin Waveguide Technology

The extinction ratio (defined as the difference in the optical power between 0-dB fiber-to-fiber loss and the off state level) is enhanced with the introduction of an S-bend waveguide structure using asymmetric twin waveguide techniques for a spot-size converter integrated semiconductor optical amplifier (SSC-SOA) with a polarization-insensitive offset superlattice. Angled waveguides are introduced in order to obtain low facet reflectivity without the need for antireflection coating. A curved waveguide is introduced to connect the angled and straight waveguide, minimizing their coupling loss while achieving a lateral spatial mode filter. The SSC-SOA, operating at 1.62-mum wavelength, achieves an extinction ratio up to 70 dB and a fiber-to-fiber gain of 10 dB using cleaved, flat end single-mode optical fibers.     

High-gain, high-power 1550-nm polarization independent MQW optical amplifier

A practical 1550-nm polarization independent semiconductor optical amplifier configuration employing compressively strained quantum wells and a few commercially available optical components is reported. Crosstalk from counter propagating light, which may easily occur in such a configuration, has been sufficiently suppressed for practical use. For the entire configuration a net fiber-to-fiber gain of 17 dB, a 3-dB saturation output power of 13 dBm and a noise figure of 9 dB have been demonstrated. The polarization dependence was only 0.7 dB. The polarization independent 1550-nm semiconductor optical amplifier reported here is attractive when power consumption and compactness are of major concern and especially for applications involving nonlinear signal processing and switching.     

27-dB gain unidirectional 1300-nm polarization-insensitive multiplequantum well laser amplifier module

An unidirectional polarization-insensitive multiple quantum well laser amplifier module for the 1300-nm window with a record high gain of 27 dB and a 3-dB saturation output power of 13 dBm is demonstrated. The module gain has a 3-dB width exceeding 60 nm and shows a typical polarization sensitivity and gain ripple as low as 0.3 dB. To provide immunity for backscattered or reflected light, polarization independent optical isolators were inserted in the input and output coupling optics of the package. A practical optical amplifier module for the 1300-nm window is very desirable, because most of the presently installed fiber has its zero dispersion wavelength around 1310 mm, while much of the older fiber often only can be operated around this wavelength     

Semiconductor optical amplifier for CWDM operating over 1540-1620 nm

A semiconductor optical amplifier was developed for coarse wavelength-division-multiplexing (CWDM) operating over 1540-1620 nm (C-L band). A unique quantum-well structure was designed to meet the requirements for the CWDM operation such as wide bandwidth, low polarization-dependent gain, and high-saturation power at the short wavelength end of the band (1540 nm). Over the band, 24-dB maximum chip gain was obtained with less than 4.3-dB gain flatness and more than 14.6-dBm saturation power.