基于三波长SLA的全光解复用器

工作在三波长状态下的SLA作为非线性元件,在光环形镜中实现OTDM信号的解复用,模拟计算表明,在保持光束功率为1W时,SLA恢复时间小于10ps,可从OTDM复用信号中提取出任一路信号,在控制脉冲功率为900mW时,带宽可达100GHz。     

Impact of gain saturation on size limitations of semiconductorlaser amplifier (SLA) based switching structures

Size limitations of optical switching structures employing semiconductor laser amplifiers arising from signal extinction ratio, amplifier gain, and optical filter bandwidth are investigated theoretically and experimentally. Simulations reveal that the maximum number of SLA that can be cascaded in an optical switching structure increases with increasing input signal extinction ratio, optical gain of each SLA and decreases with increasing SLA noise figure, optical filter bandwidth and input signal bit rate     

Influence of carrier transport on performance of SLALOM with apolarization-independent MQW SLA

The switching performance of the semiconductor laser amplifier in a loop mirror (SLALOM) with a polarization-independent multiquantum-well SLA influenced by the carrier transport is discussed. It is shown that the switching window is polarization-dependent in the case of ultra-short pulses used as switching pulses because of the carrier transport effect between quantum wells. The influence of polarization can be suppressed by modifying the polarization state of local switching pulses     

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。     

Influence of extinction ratio on performance of optical receivers incorporating laser preamplifiers

Reports the performance degradation of optical receivers incorporating semiconductor laser amplifiers (SLAs) caused by the nonzero extinction ratio of the input optical signal. The resulting sensitivity penalty dependencies on bit rate, SLA gain and facet reflectivity are also investigated. The results clearly show that the new receiver can be more affected by a finite extinction ratio compared to a conventional pin or APD receiver. Using a bandpass optical filter to reduce amplifier spontaneous emission noise will increase the extinction ratio penalty.<>     

Timing-jitter-free demultiplexing of an all-optical signal processor based on the intensity-dependent self-wavelength conversion of Raman solitons

An all-optical signal processor based on the self-wavelength conversion of Raman solitons is described. The processor consists of an erbium-doped fiber amplifier (EDFA), a highly nonlinear fiber, and an optical bandpass filter. The timing-jitter-free demultiplexing of the processor was demonstrated by an 80-km transmission experiment. Error-free bit error rate (BER) performance was achieved. Transmitted fourfold optical time-division multiplexing (OTDM) signals with a large timing jitter of about 16 ps for an OTDM signal interval of 25 ps were demultiplexed to 9.95-Gb/s signals without signal degradation.     

Optical sampling using nondegenerate four-wave mixing in asemiconductor laser amplifier

Picosecond optical sampling using nondegenerate four-wave mixing in a semiconductor laser amplifier (SLA) is demonstrated for the first time. High-peak-power pulses and electrical gating of the SLA produce an optical sampling signal with a high signal-to-noise ratio     

Time-domain modeling of semiconductor optical amplifiers for OTDMapplications

An advanced time-domain dynamical model for the investigation of semiconductor optical amplifiers (SOA) is presented. The model accounts for the ultrafast gain dynamics, the gain saturation and the gain spectral profile. It is also suitable for analyzing the amplifier in a system environment. As an example the model is used to investigate the gain dynamics of an SOA as well as the characteristics of an interferometer switch semiconductor laser amplifier in a loop mirror (SLALOM). Good agreement between modeling and experiment is shown. The model can be applied to the investigation of other optically time-division multiplexed (OTDM) applications, too     

Semiconductor laser diode optical amplifiers/gates in photonicpacket switching

In this paper, we will describe how semiconductor laser diode optical amplifiers/gates can be used in the photonic packet switching systems based on wavelength division multiplexed (WDM) techniques. First, we show that cross-gain modulation (XGM) can be suppressed when the device is used in the transparent condition of the waveguide material even when the input signal power exceeds +18 dBm. We then discuss an appropriate encoding for the optical signal. Experimental results show that high bit rate Manchester-encoding enables the use of semiconductor laser diode optical amplifiers/gates in the gain condition as well as the transparent condition. Finally, a new photonic packet receiver which utilizes a semiconductor laser diode optical amplifier as a packet power equalizer is proposed. This receiver accepts 17 dB power fluctuation at nanosecond speed for 10 Gb/s Manchester-encoded signal     

Chirp compensation capability of a semiconductor laser amplifier

Performance improvement is reported resulting from incorporating a semiconductor laser amplifier (SLA) as a post-transmitter-amplifier in long-haul directly modulated optical systems operating in the 1.5 mu m region. This improvement arises from reduction of the chirp produced by the semiconductor laser as the signal passes through the SLA. Eye closure penalty improvements in excess of 5 dB are observed for an illustrative long-haul 4.8 Gbit/s system.<>     

160-gb/s OTDM signal source with 3R function utilizing ultrafast mode-locked laser diodes and modified NOLM

High-quality 160-Gb/s optical time-division-multiplexing (OTDM) signal source with 3R functions was demonstrated using ultrafast mode-locked laser diodes (MLLDs) and a nonlinear optical fiber loop mirror (NOLM) modified with inline and external polarizers and an inline optical phase-bias compensator. Pulse quality for each OTDM channel was successfully improved and equalized owing to the clock extraction at the true data bit rate using a 160-GHz MLLD and also to the improvement of the switching performance of the NOLM.     

Comparison of interferometric all-optical switches fordemultiplexing applications in high-speed OTDM systems

We have investigated three interferometric all-optical switches based on cross-phase modulation (XPM) in semiconductor optical amplifiers (SOAs), the semiconductor laser amplifier in a loop mirror (SLALOM) switch, the Mach-Zehnder interferometer (MZI) switch, and the ultrafast nonlinear interferometer (UNI) switch. Switching windows with different widths are measured under similar conditions for all three switching configurations. We introduce the integrated contrast ratio (ICR) as a measure to evaluate the performance of a switch from switching windows. Using the ICR, the switches are compared and their application is discussed as demultiplexer in optical time division multiplexing (OTDM) systems for data rates of 40, 80, and 160 Gb/s     

Optical demultiplexing at 6 Gb/s using a semiconductor laser amplifier as an optical gate

A semiconductor laser amplifier (SLA) has been employed successfully for optical demultiplexing in two-channel optical time division multiplexed system experiments at 6 and 2 Gb/s. Demultiplexing of 6-Gb/s (2-Gb/s) signals was demonstrated with a power penalty of 1.6 dB (3.0 dB) at bit error rates of 10/sup -9/. It is also shown that a reduction of the generated amplified spontaneous emission can be obtained by optical gating/demultiplexing for systems incorporating inline amplifiers. A 0.5-dB improvement in sensitivity was achieved as a result of using an SLA for demultiplexing from 2.0 to 1.0 Gb/s in a system with one inline Er/sup 3+/-doped fiber amplifier.<>     

Impact of crosstalk induced beat noise on the size of semiconductor laser amplifier based optical space switch structures

The size limitation of a semiconductor laser amplifier (SLA) based optical matrix-vector multiplier (MVM) switch structure arising from amplifier noise and crosstalk is investigated theoretically and experimentally. Computer simulation reveals that the number of input/output channels in such a switch structure may be limited to less than 60/spl times/60 if the contrast ratio of each SLA is 20 dB or lower.     

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     

Equivalent circuit theory of spontaneous emission power insemiconductor laser optical amplifiers

An equivalent circuit model for a semiconductor laser amplifier (SLA) has been developed. This model can be used with a transfer matrix method (TMM) to analyze the performance of a SLA. The validity of the model is explored in this paper by analyzing the spontaneous emission noise power in a Fabry-Perot SLA with a uniform distribution of material gain coefficient. The result is found to be identical with that derived by the Green function approach. The physical reasons for the validity of the equivalent circuit model are also discussed, and possible further applications of the model are suggested     

SLALOM: semiconductor laser amplifier in a loop mirror

The processing of optical signals in the optical domain is an important issue resulting from the desire to take advantage of the full bandwidth of the optical fiber. In this paper, we present detailed investigations on a device, which utilizes a semiconductor laser amplifier in a loop mirror configuration (SLALOM). Different modes of operation are reported like nonlinear single pulse switching and two-pulse switching at different operation speeds (1-100 Gb/s). Furthermore, a number of applications of the SLALOM in photonic systems, like pulse shaping, decoding, retiming and time-division demultiplexing, are presented. In addition, the SLALOM can be used for an estimate of the linewidth enhancement factor α and the carrier lifetime τ _e in an SLA     

Fiber loop optical buffer

Fiber loop optical buffers enable data storage for discrete time intervals and therefore appear suitable for applications in optical asynchronous transfer mode (OATM)-based networks where data are transmitted in cells of fixed length. In this paper, the feasibility and the limitations of optical data storage in a fiber loop optical buffer are studied theoretically and experimentally, A model of a fiber loop buffer, incorporating semiconductor laser amplifiers (SLA) as switching gates, is described. The two major interfering quantities are cross talk and amplified spontaneous emission of the SLA gates. To limit the impact of cross talk on the signal quality, an on/off ratio of the SLA gates of at least 30 dB is required. The paper describes the optimum operation conditions, which enable data storage for more than 100 circulations even for data rates in the range from 10 to 160 Gb/s     

Analysis of the Physical Impairments on Maximum Size and Throughput of SOA-Based Optical Burst Switching Nodes

In this paper, the physical limitations of semiconductor optical amplifier (SOA)-based switching nodes for optical burst switching (OBS) are investigated. The investigation covers two broadcast-and-select (BAS)-based architectures. Their maximum size and throughput are analyzed for nodes at different bit rates. As main impairments for signal degradation amplifier noise, crosstalk, SOA gain saturation and dynamics, and SOA chirp are evaluated by simulations. In conclusion, general rules for design burst switching nodes are established.      

Bidirectional four-wave mixing in semiconductor optical amplifiers:theory and experiment

Bidirectional four wave mixing (FWM) is investigated in a bulk semiconductor optical amplifier (SOA) for dispersion compensation and for the clear/drop functionality in optical time division multiplexed (OTDM) systems. Good performance for bidirectional midspan spectral inversion (MSSI) is theoretically predicted for bit rates of 10, 20, and 40 Gb/s and is shown to be in agreement with measurements performed at 10 and 20 Gb/s. Measurements of the clear/drop functionality using the bidirectional technique show excellent performance for a 4×10 Gb/s signal and is again in good agreement with simulations. The clear/drop functionality is also simulated for 4×20 Gb/s and 4×40 Gb/s signals