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A 40-Gb/s 3R regenerator with a two-ring injection mode-locked fiber laser as the clock recovery and an electroabsorption modulator (EAM) as the reshaping optical decision gate is proposed and demonstrated. The cross-absorption modulation effect in a bulk EAM was also numerically modeled. Using this model, both the shape and the extinction ratio of the optical decision gate are optimized. The model is also employed to investigate the tolerance of the timing jitter, the chromatic dispersion, and the polarization mode dispersion of an all-optical 3R regenerator based on a bulk EAM decision gate. The operation margin of the 3R regenerator is presented. The theoretical results agree well with the experimental results

The performance of a multiwavelength continuous-wave (CW) optical source based on a supercontinuum (SC) has been numerically studied in a 10 Gb s−1 dense wavelength division multiplexed transmission system. The Q factor is calculated as a measure of the system performance. Effects of the bandwidth of the arrayed-waveguide-grating filter, the transmission fibre input power, and the SC spectral flatness on the Q factors are presented. A multichannel equalization filter is used to improve the performance of the multiwavelength CW optical source and good results are obtained. A comparative study of different modulation formats, non-return-to-zero and return-to-zero, is also performed to evaluate their tolerance to linear and nonlinear impairments.

Optical clock division and multiplication were realized with an injection mode-locked fiber ring laser based on semiconductor optical amplifier SOA owing to the relatively long recovery time of carriers in SOA and the rational harmonic mode-locking. Second frequency division and 1.5th frequency multiplication of 10 GHz , second and 3 4 th frequency division of 20 GHz optical pulse trains were realized, respectively, in the experiment.

A novel clock recovery scheme using two-ring injection mode-locked fiber ring laser based on all 10 GHz bandwidth components was demonstrated. With this scheme, the clock with low timing jitter was obtained from a degraded 10 Gb/s optical data stream. Optical clock recovery was also achieved from a degraded 20 Gb/s optical data train when the clock division technique in the opto-electronic oscillator (OEO) and the rational harmonic mode-locking technique in the fiber ring laser were applied. No pattern effect was observed in the experiments.

A novel method was suggested about pedestal reduction and chirp elimination of high-order compressed solitons by using SOA and tunable filter. Results of numerical simulation demonstrate that, under certain conditions, the pedestals and chirp can be successfully mitigated without pulse broadening.

A theoretical study of active mode-locking fiber loop laser using semiconductor optical amplifier (SOA) was presented in this paper. The effects of linewidth broadening factor of SOA on active mode-locking were investigated originally. The relations between parameters of output pulse series and the critical parameters of SOA and other elements in fiber loop were obtained.

A 10-GHz fiber-integrated ring laser incorporating a semiconductor optical amplifier and an electroabsorption modulator was investigated both theoretically and experimentally. The time-domain ABCD law was employed to clarify the impacts of optical elements on the mode-locked pulses. The obtained analytical results were testified by the experimental ones. Such a ring laser also showed good performance as an optical pulse source, which generated a stable pulse train with a pulse width of 10 ps and a tunable wavelength range of 30 nm.

A novel configuration was demonstrated to realize dual-wavelength operation in an erbium-doped fiber ring laser by incorporating a pair of multiplexer/demultiplexer. The repetition rate of each channel can be separately changed by adjusting a delay line associated with that channel in the cavity without changing the radio frequency. Dual-wavelength pulses at 2.5 and 5 GHz respectively were simultaneously obtained with pulse widths of 17.7 and 13 ps.

Some characteristics of supercontinuum generation in the dispersion-shifted-fiber are studied both in theory and experiment. The theoretical research shows how the fiber nonlinearities, such as self-phase-modulation, four-wave-mixing and cross-phase-modulation, play their roles in the supercontinuum generation. Some dependent parameters of supercontinuum generation, such as the fiber length, the pump power are also discussed in this paper. The experimental results agree well with the theoretical simulations.

In this paper, the theoretical model of the UNI is proposed in detail, which counts on the ultrafast nonlinearities and longitudinal effects of semiconductor optical amplifier (SOA). The transfer function of UNI is also obtained. The switching window, which is a key parameter for demultiplexer, is then analyzed. It's shown that the switching window properties are determined by the length of SOA, the length of the birefringence fiber (BRF), and the parameters of control pulses such as control pulse energy, pulsewidth, power.

In this paper, the properties of the demultiplexing module using the serialized nonlinear optical loop mirrors have been investigated. The noise of the demultiplexing output has been discussed in detail. The influences of the switches' settings on the noise and the properties of the bit error rate of each demultiplexing channel have also been investigated. It is shown that the power penalty of the demultiplexing module in a serial structure using the nonlinear optical loop mirrors is much lower than that in the parallel structure and it will be very small if the settings of the loop mirrors are carefully chosen

The time-domain ABCD matrix formalism is based on the propagation of a Gaussian pulse which is characterized by the pulsewidth and chirp. In this paper, we will perfect this method and derive time-domain ABCD matrices for more optical devices. Especially, we extend this perfected theory to analyze the principle of passive mode-locking by reasonable approximation though, as we know, the output pulse generated from passive mode-locking fiber laser is of sech-shape. It is attractive because it can present a fairly apparent view to understand the mechanism of fiber lasers as well as analytic results to understand the pulse characteristics.

Without any stabilization equipment, multiwavelength laser oscillation was obtained in Erbium-doped fiber laser, basing on a section of standard multimode optical fiber which was twined as a polarization controller (PC). The number of lasing wavelength and wavelength spaces can be controlled by changing the state of PC.

In this paper, the properties of the optical phase-locked loop(PLL) based on the four-wave mixing in the semiconductor laser amplifiers (SLAs) are discussed. The components that achieve the function of detecting the bit phase of the input optical signal are concerned and discussed in detail together as a function module named as the optical bit phase detector referred to the general electronic PLL. Therefore, most of the properties of the optical PLL can be analyzed by applying the general phase-locked theory. Here the stability of the optical PLL is discussed. It's shown that the variance of input signal power in the practical application will cause optical PLL system unstable because of its long loop delay. The influence on the output phase jitter of the optical PLL is also investigated.

The effect of filter characteristics on the output performance of actively mode-locked fiber ring lasers has been studied experimentally and numerically, with the same 3-dB bandwidth, the filter that has a flatter wavelength response tends to generate narrower soliton-like pulses.

The q-parameter and the ABCD law are useful tools for analyzing the propagation or oscillation behavior of the spatial Gaussian laser beam. In this letter, we apply these tools to the theory of the actively mode-locked Er/sup 3+/-doped fiber laser (AML-EDFL). Based on the q-parameter definition, we derive the ABCD matrices for the four primary elements which influence the pulse forming in the AML-EDFL, including the amplitude modulator, the optical filter, the fiber with dispersion, and the fiber with nonlinearity. With the aid of the split-step q-parameter processing algorithm, the laser characteristics versus some typical laser parameters are investigated in detail.

A simple optical sampling scheme for ultra-high speed optical A/D conversion is demonstrated. 10GHz microwave signal is sampled using 10ps optical pulses generated by a mode lock laser, and 6 bits resolution is achieved.

All-optical clock recovery is the key technology in 3R all-optical regeneration. In this paper, to reduce the pattern effect in a bit clock recovering using injectied mode-locked laser based on semiconductor optical amplifier (SOA), we propose a novel technology named nonlinear polarization rotation, which is proved to be very effective by numerical calculation.

Summary form only given. The optical period-doubling behavior is a nonlinear phenomenon observed in the laser with periodical modulation and saturated absorption. Recently, the semiconductor laser amplifier in loop mirror (SLALOM) has been extensively investigated as an ultrahigh-speed optical switch. Employing the SLALOM as an optical modulator, a mode-locked fiber laser has been demonstrated to generate a high-speed periodically optical pulse sequence for optical clock recovery. We present that optical period-doubling sequence which can be implemented in a fiber laser with a SLALOM with the low bias current of the SLA and a high optical power in the laser cavity. It has the potential applications in optical clock division. Comparatively, an optical periodical sequence has also been realized in this laser with the high bias current of the SLA and a low optical power in the laser cavity.

We demonstrate an optical time division demultiplexing from 8x2.5Gb/s pseudorandom data stream using a nonlinear optical loop mirror, or nonlinear fiber Sagnac interferometer switch. To ensure good extinction ratio of the demultiplexed signal, some experimental results show it is necessary to adjust carefully the dc bias, modulation current, compression fiber length and switching width and synchronous between the data and control pulses.

In this paper, a 2 X 2.5 GHz to 2.5 GHz optical time division demultiplexer by using a kind of asymmetry nonlinear optical loop mirror was studied both theoretically and experimentally for the first time in China. The final extinction ratio was as high as 8 dB.

Recent studies on basic technologies including optical pulses generation and amplification for soliton transmission are reviewed. Demultiplexing for future OTDM soliton communication is also presented.