Yan Lianshan

Gain Improvement of Fiber Parametric Amplifier via the Introduction of Standard Single-Mode Fiber for Phase Matching

We investigate and experimentally demonstrate the gain improvement of single-pump fiber parametric amplifiers by using a suitable length of standard single-mode fiber (SSMF) inserted between two high-nonlinear fibers (HNLFs). The SSMF with different dispersion properties from the HNLF is employed for phase matching of the parametric processes, and the signal gain is improved as compared with the absence of the SSMF with experiment results. Furthermore, the effect of the input pump power and the fiber length of the SSMF on the output signal gain are discussed with experimental investigation.

Quantifying Information Flow between Two Chaotic Semiconductor Lasers Using Symbolic Transfer Entropy

Symbolic transfer entropy (STE) is employed to quantify the dominant direction of information flow between two chaotic-semiconductor-laser time series. The information flow in unidirectionally and bidirectionally coupled systems was analyzed systematically. Numerical results show that the dependence relationship can be revealed if there exists any coupling between two chaotic semiconductor lasers. More importantly, in both unsynchronized and good synchronization regimes, the STE can be used to quantify the direction of information flow between the lasers, although the former case leads to a better identification. The results thus establish STE as an effective tool for quantifying the direction of information flow between chaotic-laser-based systems.

The optimization of radio over fiber link by proper link gain control

We demonstrate the adjustability of optimal input power (OIP) of the radio over fiber (RoF) link by proper link gain control in the central unit (CU) and remote antenna unit (RAU). The experiment results show that the reading and writing distance (RWD) of the radio frequency identification (RFID) service and the throughput of the WiFi service have a max increase of 3cm and 6.975Mbit/s respectively when the OIP value equals to output power of commercial products, compared with OIP value with 5-dBm right/left shift to the output power.

Simultaneous transmission of RFID, WIFI and ZigBee over fiber

We present a radio over fiber system supporting the simultaneous transmission of RFID, WIFI and ZigBee. Though using the inexpensive components, ZigBee can achieve a transmission distance more than 60 km; we also discuss the factors affecting the transmission distance of WIFI and RFID.

Time-Delay Signature of Chaotic Vertical-Cavity Surface-Emitting Lasers with Polarization-Rotated Optical Feedback

To quantitatively evaluate the time-delay (TD) signatures of chaotic signals generated by vertical-cavity surface-emitting lasers (VCSELs) with polarization-rotated optical feedback (PROF), we propose four cases of resolution coefficients R based on correlation functions. The resolution coefficient characteristics for the x-polarization (XP) mode, y-polarization (YP) mode and the total output are considered. The dependences of R on the feedback strength and feedback delay are discussed and compared carefully. The two-dimensional maps of R show that the TD signatures for the single polarization mode (i.e., XP or YP mode) are much more difficult to retrieve than those for the total output in the entire parameter space. Thus, by using single polarization mode as a chaotic carrier, the TD signatures are extremely difficult to be identified, which contributes a lot in the security-enhanced VCSELs-based chaotic optical communication systems.

Simultaneous PMD Mitigation for Two Polarization Tributaries of a PDM Signal using only One All-Optical Regenerator

A scheme of polarization-mode-dispersion (PMD) mitigation in a polarization-division-multiplexing (PDM) system is proposed and demonstrated with 2×10Gb/s return-to-zero on-off-keying (RZ-OOK) transmission. Simultaneous mitigation for two polarization tributaries of the PDM signal is achieved based on the self-phase-modulation (SPM) effect and offset filtering in a polarization nonlinear loop configuration. The improvement of eye-diagram-based signal-to-noise ratio (SNR) is 3.5 dB in the presence of a 7.2-ps differential-group delay (DGD) when the pulsewidth of the PDM signal is ~16.6ps.

Numerical Investigation and Optimization of SBS-Based Slow-Light Using Filtered Incoherent Pump

The performance of stimulated Brillouin scattering (SBS)-based slow light using a novel spectrally-sliced broadband incoherent pump source is numerically studied. The profile of the pump-power spectrum is determined by the transmission spectra of the optical filter followed by the polarized broadband incoherent pump source. We also investigate the performance of Gaussian-type and super-Gaussian-type filtering under different spectrally-sliced bandwidths and pump power levels for 2.5 Gbit/s return-to-zero pulse (50% duty-cycle). The pulse broadening is characterized by the full width of half maximum (FWHM) and the rms pulse width, respectively. However, the results obtained by the two kinds of measurement methods deviate from each other with increasing pump power. Compared with the regular Gaussian-type filtering, the pulse broadening can be significantly reduced using super-Gaussian-type filtering at the cost of a small reduction in delay time. Furthermore, the maximum improvement in pulse broadening of ?BFWHM = 28.4% and ?BRMS = 10.4% is achieved by using a five-order super-Gaussian-type filter and a pump power of 500 mW.