基于掺锗光子晶体光纤的可调谐多波长转换器

为了提高光网络中波长资源的使用效率,利用光纤中瞬态受激拉曼散射效应分析理论,设计了一种基于掺锗光子晶体光纤的可调谐四通道波长转换器。由于受激拉曼散射效应的增益随信号光与探测光波长之间的频移量变化,波长转换器各个转换信道波长可由探测光波长调谐。分析了泵浦信号光输入功率对多波长转换器性能的影响,结果表明:随着输入泵浦功率的增大,多路波长转换器的转换性能更好。用OptiSystem对四通道可调谐波长转换进行仿真,结果表明:所设计的波长转换器能够同时实现四通道波长转换,各信道波长可在1 511~1 569nm进行调谐。     

Design and analysis of all-optical up- and down-wavelength converter based on FWM of SOA-MZI for 60 Gbps RZ data signal

In this paper, the design and analysis of the all-optical up- and down-wavelength converter based on four-wave mixing (FWM) effect of semiconductor optical amplifier Mach–Zehnder interferometer (SOA-MZI) have been presented. The return-to-zero (RZ) modulated data signal at a bit rate of 60 Gbps has been evaluated for error-free operation to show the feasibility of proposed system at different pump wavelength. The converted signal power and quality factor are investigated as the function of variable signal power and pump power. The optimized operating input signal power of ?5 dBm with Q-factor of \(\sim \)28 dB for RZ modulated signal by using SOA-MZI structure with enhanced FWM effect. The important contribution of these investigations that it is possible to expand the optical network with limited available channel bandwidth by utilizing the wavelength converter and gives an approach to implement wavelength converter for future hybrid optical access networks.     

All-optical Mach-Zehnder wavelength converter with monolithicallyintegrated preamplifiers

An interferometric wavelength converter with preamplifiers for both the signal input and the continuous-wave probe input is presented. The dynamic range of the device is enhanced: penalty-free conversion is demonstrated at 2.5 Gb/s for input powers ranging from -6 to +4 dBm. Transmission of the converted signal over 480 km of standard fiber shows penalty improvement relative to the unconverted, information-limited signal     

波分复用-光时分复用波长转换信号的消光比研究

对基于半导体光放大器(SOA)交叉增益调制(XGM)效应的全光波分复用一光时分复用(WDM—OTDM)转换后的两路时分复用输出信号的消光比(ER)特性进行了分析。研究了两路波分复用的输入抽运光和探测光的功率、波长、抽运光的消光比、数据速率以及半导体光放大器的偏置电流、腔长和模场限制因子对转换信号消光比的影响。模拟结果表明，增大抽运光输入功率，选择长波长抽运光，可以增加转换光相应信道消光比，但减小了相邻信道的输出消光比；增加抽运光消光比，可以提高转换光消光比，但各个信道增长幅度不同；减小探测光输入功率，选取短波长探测光波长，增加半导体光放大器的腔长和模场限制因子以及大的偏置电流可提高转换光消光比；对于两路或多路波分复用信号转换时分复用信号的过程中，一定要考虑转换光每个信道消光比的均衡。     

Tunable wavelength conversion in a semiconductor-fiber ring laser

A tunable wavelength converter is demonstrated using highly nondegenerate four-wave mixing in a semiconductor-fiber ring cavity with no external pump light and low input signal power requirements. This device allows continuous tuning of both pump and converted wavelengths over the semiconductor optical amplifier gain bandwidth. Results for 11.8-nm down- and 6.9-nm up-wavelength conversion with input signal power as low as -10 dBm have been obtained at 1 Gb/s with less than 1.6-dB power penalty     

基于光纤光栅外腔半导体激光器增益饱和效应的全光波长转换实验研究

对基于光纤光栅外腔半导体激光器增益饱和效应的全光波长转换器的静态与动态特性进行了实验研究。为消除反馈光与转换信号输出光对光源的不利影响及提高光输入、输出信号耦合效率 ,提出了采用环形器进行信号耦合的光学结构。实验结果表明 ,转换器件具有高于 30nm的波长转换间隔 ,并可实现波长上、下转换。进行了15 5Mbit/s伪随机码调制信号的动态波长转换实验。     

All-optical frequency conversion in a traveling-wave semiconductorlaser amplifier

All-optical frequency conversion over the entire gain spectrum of a traveling-wave semiconductor laser amplifier is analyzed by numerical solution of a nonlinear wave equation system. The wavelength dependence of the gain coefficient g, the linewidth enhancement factor α, the differential gain dg/dN, and the gain saturation effect are contained in the model. The method yields a high conversion efficiency and a converted signal output power up to 10 dBm is obtainable. It is shown that the input signal power can vary by three orders of magnitude with nearly no degradation of the conversion efficiency. By means of the input powers, the conversion efficiency can be maximized. The dependence of the conversion efficiency is analyzed for fixed input powers. Simultaneous conversion of an optical data signal to several wavelengths is analyzed. The requirements for the output filter are outlined     

Ultrawideband Wavelength Conversion Using Cascaded SOA-Based Wavelength Converters

An all-optical wavelength converter with a large wavelength hopping range is proposed and demonstrated. This converter consists of multistage cascaded wavelength converters using semiconductor optical amplifiers each with different gain band. Each of the cascaded wavelength converters enables us to perform both noninverted (NIV) and inverted (IV) operations. Conversion performance is compared at NIV and IV operations in terms of static characteristics as a function of input/output power of the converter. While good conversion performances are achieved at both operations, the IV wavelength conversion has better cascadability to obtain a high-quality converted signal for the cascaded scheme. Moreover, signal amplitude regeneration is demonstrated by repeating the IV wavelength conversion. Finally, we successfully demonstrate, for the first time, ultrawideband wavelength conversion, including over 300-nm wavelength hopping to the shorter wavelength side with a triple-stage cascaded wavelength converter     

10-Gb/s low-input-power SOA-PLC hybrid integrated wavelength converter and its 8-slot unit

We achieved successful low-input-power (-10 dBm) wavelength conversion at 10 Gb/s by using a hybrid integrated cross-phase modulation wavelength converter (XPM-WC). The input CW power was also -10 dBm and the total current was only 215 mA, and no signal preamplifiers were used. From the relationship between the eye-opening ratio and the injection current to the SOA, we clarified the optimal current condition for low-input-power operation. The XPM-WC consists of a two-channel spot-size converter integrated semiconductor optical amplifier (SS-SOA), which is mounted on a planar lightwave circuit (PLC) platform. We also fabricated an 8-slot unit. XPM-WC modules are inserted in every slot and can operate independently. Stable and uniform low-input-power operation is confirmed in all slots.     

Characteristics of the Wavelength Converted Signal in Wavelength Conversion Based on Cross-Gain Modulation

An analytical theory describing the frequency chirp characteristics of the wavelength converted signal in wavelength conversion based on cross-gain modulation (XGM) in semiconductor optical amplifier (SOA) is derived. By computation, we can see that low input pump power, high probe power, small line-width enhancement factor and low unsaturated single-pass gain of the SOA are favorable for reducing the frequency chirp of the wavelength converted signal. The analytical results have significance in understanding and designing wavelength converters.     

Analysis of wavelength conversion using a multisection DBR laserwith a saturable absorber

The static performance of a wavelength converter obtained by a multisection distributed Bragg reflector (DBR) laser with a saturable absorber between two gain sections is analyzed. For this device an optical input signal at one given wavelength is converted into an output signal at the lasing wavelength. The performances are evaluated in terms of conversion efficiency, suppression ratio, and minimum input power needed for wavelength conversion. It is shown that a proper choice of the injected signal wavelength with respect to the lasing wavelength enhances the conversion efficiency and the suppression ratio and reduces the switching power. The performance can be enhanced also by increasing the electrical current applied to the first gain section provided that the second gain section is biased above the transparency level. The authors have shown that reduction of the front facet reflectivity results in a dramatic increase for the conversion efficiency. The sensitivity to the electrical bias condition and to the resonant condition of the injected signal with respect to the cavity has also been investigated     

Tuning technique to optimize input power of a cross-phase modulation wavelength converter

This paper proposes a tuning technique to optimize the input power of a cross-phase modulation wavelength converter (XPM-WC). The focus is on an output signal whose wavelength is the same as the input signal. The optimum input power can be easily set by keeping the output signal (not converted signal) power constant. Input continuous-wave (CW) power should be increased or decreased with increasing or decreasing input signal power so that the output signal power stays fixed at the optimum level. Observing the eye pattern of the converted signal is unnecessary. Wavelength conversion from a fixed optical channel to a random one (30 channels with 100-GHz spacing) is successfully demonstrated by using this technique. A low-power penalty (<1dB) and a low-power fluctuation (<1dB) were confirmed in all optical channels. An XPM-WC unit containing a variable CW light source and its level controller were fabricated and simultaneous and automatic operation was confirmed.     

Using multimode Fabry-Perot laser without external-injection for wavelength conversion

Proposed and experimentally investigated is an all-optical wavelength converter using a multi-quantum-well multi-longitudinal-mode Fabry- Perot laser diode without any external probe beam or external built-in cavity. The input wavelength can be converted at 2.5 Gbit/s by the converter and the power penalty of 3.5 dB is observed at a bit error rate of 10^-9. The proposed converter apparatus is simple and costeffective for wavelength division multiplexing network applications.     

Folded-path self-pumped wavelength converter based on four-wave mixing in a semiconductor optical amplifier

A four-wave mixing wavelength converter with no external pump laser and very low input signal power requirements is characterized. The wavelength conversion occurs inside a high-reflection/antireflection coated semiconductor optical amplifier pigtailed with a fiber Bragg grating. The pump signal is provided by the lasing mode at the Bragg wavelength. A 1-mW optical signal modulated at 2.5 Gb/s is converted over 9 mm with error rates below 10/sup -9/.     

Analysis of Digital System Performance in EAM-Based Photocurrent Driven Wavelength Converter

This work describes the factors that influence the digital system performance of a monolithically integrated photocurrent driven wavelength converter. For an optimized input power to the receiver section of the device, experiments show <1-dB power penalty for conversion between 1548 and 1563 nm at 10 Gb/s. Under optimized conditions, performance is limited by the output extinction ratio of the converted signals     

低功率抽运光纤参量振荡器的时钟提取抖动性能

采用两次光调制技术将非归零(NRZ)码数据转换成归零(RZ)码光信号后,利用光纤参量振荡器(FOPO)结构实现了较低光功率抽运下的参量波长转换和时钟提取功能。实验表明,对于波长转换间隔为1.6nm的10Gbit/s时钟提取,优化的输入抽运光功率范围是8～14dBm;当输入信号的幅度抖动和相位抖动分别大于2.28mV和3.5ps时,该时钟提取系统可实现抖动抑制功能,其输入/输出抖动转移曲线斜率约为0.29和0.16。     

Improvement of the input power dynamic range for wavelengthconverters based on cross-gain modulation employing a probe powercontrol loop

A technique for improving the input power dynamic range of wavelength converters based on cross-gain modulation in a semiconductor optical amplifier is presented. By experimentally investigating the effect of pump and probe powers on the operating performance in terms of power penalty for a conventional wavelength converter, we show that the optimal performance depends on the ratio of pump and probe powers coupled into the semiconductor optical amplifier in a certain input power range. Based upon the experimental result, a wavelength converter with a wide dynamic range has been proposed, in which the probe power is automatically adjusted to have the power proportional to the pump power. We show that a dynamic range of >20 dB is achievable for a 2.5 Gbit/s signal at a 2-dB penalty     

Theoretical Study on Wavelength Conversion Based on Cross Phase Modulation Using Semiconductor Optical Amplifiers

Performances of wavelength converted signal by cross phase modulation (XPM) using semiconductor optical amplifiers (SOA's) were studied by the use of the multi-section model. Results show that they are related to both the phase arm bias current of the XPM wavelength converter and its operation. When the conversion is under the in-phase operation, the peak extinction ratio (ER) and the chirp frequency of the converted signal increase according to the decrease of the phase arm bias current, but the input signal power dynamic range decreases. When the converter is under the out-of-phase operation, the chirp frequency decreases with the decrease of the phase arm bias current, while the peak ER and the input power dynamic range keep almost the same when the phase arm bias current changes.     

160 Gbit/s SOA all-optical wavelength converter and assessment of its regenerative properties

The retiming and reshaping properties of a 160 Gbit/s all-optical wavelength converter based on a semiconductor optical amplifier gating delay interferometer configuration is investigated. 160 Gbit/s operation is performed with as little as -3.5 dBm input signal.     

Performance analysis of wavelength converters based on cross-gainmodulation in semiconductor-optical amplifiers

An analytical theory describing all-optical wavelength converters based on cross-gain modulation (XGM) in semiconductor-optical amplifiers is derived. Our theory consists of two parts: a large-signal analysis yielding the transmission function for the signal, and a small-signal analysis in order to describe the transformation of the signal and probe intensity noise. Both the large-signal as well as the small-signal theory reveal similar performance for the co- and the counterpropagating injection scheme for bit rates up to 2.5 Gb/s. This is confirmed by computer simulations. Consequently, the counterpropagating configuration is preferable because the implementation is simpler and conversion to the same wavelength is possible. In order to increase the conversion efficiency it is better to reduce the average signal power than to increase the probe power, which additionally reduces the output power range. However, there is a tradeoff between conversion efficiency and output extinction ratio. According to the small-signal analysis, the relative-intensity noise (RIN) due to the probe and due to the amplified spontaneous emission is negligible. Moreover, the converted signal has a lower RIN than the input signal