Xueyan Zheng

All-optical wavelength conversion of short pulses and NRZ signals based on a nonlinear optical loop mirror

Wavelength conversion of short pulses at 10 GHz based on a nonlinear optical loop mirror (NOLM) is experimentally and numerically investigated for the case of small group velocity dispersion and walkoff between the control pulses and continuous lightwaves. Experimental and numerical simulation results show that the pulsewidths of the converted signals at different wavelengths are almost the same, and the pulsewidths are compressed when the peak power of the control pulse is smaller than a certain value. An RZ optical source containing eight wavelengths having a high sidemode suppression ratio, equal amplitudes and almost the same pulsewidths is obtained by using wavelength conversion in a NOLM consisting of a common dispersion shifted fiber. 10 Gb/s NRZ wavelength conversion based on the NOLM is demonstrated for the first time and certain conclusions in some of the references are confirmed by our experimental results.

Receiver optimization for 40-Gb/s optical duobinary signal

The optimized optical receiver for a 40-Gb/s optical duobinary signal is investigated by simulation. It is found, that by optimizing the optical filter and the electrical filter in the receiver, the sensitivity of the optical duobinary can be improved greatly; meanwhile, the high dispersion tolerance nature of the optical duobinary signal will not be degraded.

40-Gb/s all-optical wavelength conversion based on a nonlinear optical loop mirror

All-optical wavelength conversion based on a nonlinear optical loop mirror (NOLM) at 40 Gb/s is demonstrated for the first time. The effect of walkoff time between control beam and signal beams is investigated when the NOLM is used as an all-optical wavelength converter or an all-optical demultiplexer.

Simultaneous realization wavelength conversion and signal regeneration using a nonlinear optical loop mirror

Wavelength conversion and signal regeneration are realized simultaneously by employing a nonlinear optical loop mirror (NOLM). The experiments demonstrate that the NOLM has strong regenerative capability when it is used as wavelength conversion media. Proper choice of the initial state of the polarization controller in the NOLM can enhance the extinction ratio of the converted signal.

8 x 40 Gb/s 55-km WDM transmission over conventional fiber using a new RZ optical source

A multiwavelength RZ optical source with equal amplitudes and pulsewidths is successfully obtained by using wavelength conversion in a nonlinear optical loop mirror consisting of a common dispersion shifted fiber. The converted wavelengths of the eight signal pulses are in agreement with the ITU-T proposal and a commercial arrayed-waveguide grating is used for demultiplexing in the frequency-domain. By using the new source 8/spl times/40 Gb/s WDM transmission over 55 km conventional fiber was realized.

New types of 2 x 2 wavelength-switching blocks for optical cross-connects

Two types of modular 2/spl times/2 wavelength-switching blocks are proposed in this letter. A 2/spl times/2 fixed wavelength-switching block can cross-connect two fixed channels between two fibers, and a 2/spl times/2 tunable wavelength-switching block can cross-connect any two channels between two fibers. These modular blocks can be used to build scalable multiwavelength cross-connects in optical networks.

Cascadability improvement of semiconductor optical amplifier based gates using polarization multiplexing technique

Abstract Cascaded semiconductor optical amplifier (SOA) gates using polarization multiplexing technique (PMT) are experimentally demonstrated for the first time. The penalty is smaller than 1 dB after three SOA gates. Numerical simulation shows that cascaded SOA gates operated at single-channel can endure some gain polarization sensitivity (GPS) of the SOA, but, even a small GPS will rapidly reduce the number of cascaded SOA gates operated at multi-channels. Experiment shows that in addition to GPS, four-wave mixing (FWM) will also affect the performance of SOA gates when operated in a multi-channel system.

Fully reconfigurable 2x2 optical cross-connect using tunable wavelength switching modules

Wavelength division multiplexing (WDM) not only increases fiber transmission capacity but also simplifies network operation by introducing the . optical path layer concept 111. Multi-wavelength optical cross-connects (OXC) are key elements in reconfigurable WDM networks.

Wavelength conversion based on cross-phase modulation in a semiconductor Mach-Zehnder modulator

Wavelength conversion based on cross-phase modulation in a reversely biased semiconductor Mach-Zehnder modulator is proposed and successfully demonstrated in a commercial device. The converted signals exhibit extinction ratio >13 dB and penalty <1.5 dB at 10 Gb/s for both NRZ and RZ formats.

Interferometric crosstalk suppression using polarization multiplexing technique and an SOA

Summary form only given.Interferometric crosstalk is one of the biggest issues in transparent wavelength-division-multiplexing networks, and should be overcome by either decreasing the crosstalk level from the components, or employing effective techniques to suppress its impact. We use a gain-saturated semiconductor optical amplifier to suppress the impact of interferometric crosstalk, and show that 6 dB more crosstalk can be tolerated for 1 dB penalty at 10 Gbit/s. Using polarization multiplexing of optical signals modulated by data and the complementary, impairments such as waveform distortion and extinction ratio degradation are eliminated, and the method is also bit rate transparent.