We propose and demonstrate experimentally a novel scheme to realize all-optical up-conversion and wavelength-conversion based on the bi-directional-pump four-wave mixing (FWM) effect in high nonlinear fibers (HNLFs).The pump is generated with optical carrier suppression in a Mach-Zehnder modulator.The two pumps are always parallel and phase-locked.A balance-detection photo-detector for optical signal detection is employed with 3-dB improvement in power penalty.The 2.5-Gb/s signals are transmitted successfully over the 25-km single-mode fiber in 30-GHz radio over fiber (ROF) systems.
An experimental demonstration of an all-optical sampling orthogonal frequency division multiplexing (AOS-OFDM) transmission system with inline chromatic dispersion (CD) compensation is carried out to test the nonlinear influence. With five subcarriers non-return-to-zero (NRZ) modulated, the total bit rate is 50 Gb/s without polarization multiplexing. The receiver end is highly simplified with direct detection using optical Fourier transform filter. After transmission in 160-km standard single-mode fiber (SSMF) link with 130-ps/nm residual CD, an optimum input optical power for the system performance is achieved.
A novel method to improve the phase coherence of optical pulse train with wavelength conversion based on cross-phase modulation and four-wave mixing effects in high nonlinear fiber is proposed.The method is experimentally demonstrated and the phase coherence of the pulse train from the mode-locked fiber laser is greatly improved.The improvement of the pulse quality is characterized in time and frequency domain.
A novel all-optical method for ultra-wideband (UWB) monocycle pulses generation based on cross polarization modulation (CPM) effect in highly nonlinear photonic crystal fiber is proposed and demonstrated.Due to the CPM effect between the probe light and the pump pulse,a pair of polarity-reversed Gaussian pulses is produced.After proper differential delay,an UWB monocycle pulse with 84-ps width and the fractional bandwidth of 153% is generated after photodetection.
State Key Laboratory on Integrated Optoelectronics,Tsinghua National Laboratory for Information Science and Technology(TNList),Department of Electronic Engineering,Tsinghua University,Beijing 100084,ChinaAbstract:The performance of a novel all-optical sampling orthogonal frequency division multiplexing(OFDM) system is proposed and analyzed.Time delays and phase shifters are used to realize all optical forward/inverse discrete Fourier transform(DFT/IDFT).Different system configurations are tested and analyzed to optimize the performance,including the system capacity,modulation formats,DFT/IDFT constructions,and the width of the sample pulse.The 50-and 100-Gb/s real-time all-optical sampling(AOS) OFDM systems are investigated.All results are analyzed,and useful suggestions are offered for future high-speed applications.
A phase pre-emphasis technique used in an all-optical sampling orthogonal frequency division multiplexing (AOS-OFDM) system is proposed and demonstrated. With the application of this technique, 50-Gb/s AOS-OFDM data are successfully transmitted over 20-km uncompensated single-mode fiber (SMF) with real-time direct-detection. The constructive interference effect between symbols is decreased with this technique.
