Xin Xiangjun

Broadband Convergence of 40 GHz-ROF and 10-Gb/s WDM-PON Systems in the Duplex Access Network

A broadly converged 40G-ROF and 10-Gb/s WDM-PON multi-service access system is proposed and experimentally demonstrated. This scheme consists of an integrated system of 40G-ROF and 10-Gb/s WDM-PON simultaneously transmitting independent 2.5-Gb/s wireless and 10-Gb/s wire signal. At the base station, it employs a remodulation scheme, which is achieved by remodulating the upstream OOK signal on the DPSK downstream signal, to reduce the cost of the base station. The transmission experiment is carried out over a 25-km-long single mode fiber (SMF-28). The results show that the sensitivities of downstream PON and ROF signal are ?14.5 dBm and ?21.5 dBm, respectively, and the sensitivity of upstream signal is ?25.3 dBm.

Cross-layer design and ant-colony optimization based routing algorithm for low earth orbit satellite networks

To improve the robustness of the Low Earth Orbit (LEO) satellites networks and realise load balancing, a Cross-layer design and Ant-colony optimization based Load-balancing routing algorithm for LEO Satellite Networks (CAL-LSN) is proposed in this paper. In CAL-LSN, mobile agents are used to gather routing information actively. CAL-LSN can utilise the information of the physical layer to make routing decision during the route construction phase. In order to achieve load balancing, CAL-LSN makes use of a multi-objective optimization model. Meanwhile, how to take the value of some key parameters is discussed while designing the algorithm so as to improve the reliability. The performance is measured by the packet delivery rate, the end-to-end delay, the link utilization and delay jitter. Simulation results show that CAL-LSN performs well in balancing traffic load and increasing the packet delivery rate. Meanwhile, the end-to-end delay and delay jitter performance can meet the requirement of video transmission.

155 Mb/s-10 Gb/s combined FSK-IM/optical label-packet modulation signals 100 km transmission over standard single mode fiber using mid-span spectral inversion by four-wave mixing in an SOA

This paper introduces the mid-span spectral inversion by four-wave mixing in a commercially available semiconductor optical amplifier (SOA) with a length of about 1.5 mm to optical label switching network based on combined frequency shift keying (FSK)-intensiy modulation (IM)/optical label-packet modulation to overcome the dispersion limitation of fiber. The 155 Mb/s–10 Gb/s combined FSK/IM signal is experimentally transmitted over a 100 km standard single mode fiber. 10−10 and 10−9 BER (bit error ratio), or even better, is achieved for the FSK label and IM packet, respectively. The –19 dB power conversion efficiency is obtained for –1 nm wavelength detuning.

Review of coded modulation free space optical communication system

This paper presents a constructive discussion and inclusive review on advancements in the coded modulation free-space optical (FSO) communication system and corresponding techniques. These techniques mainly include channel model, forward error correction (FEC) and modulation schemes. Firstly, a complete view of FSO system is presented which contains the description, the current research situation along with the advantages over the traditional radio frequency (RF) wireless communication and fiber optical communications. Then, the channel model, FEC, modulation schemes and complete system of coded modulation FSO are analyzed successively. At last, the review work of coded modulation FSO system is summarized and further improvements are prospected.

Power transmission over optical fiber networks

In this work, we report experimental results regarding the recycling of optical pumps signal for energy conversion, namely optical pumps from Raman amplifiers and fiber optic parametric amplifiers. Therefore, we propose the usage of optical signals to power remotely located network elements. After propagation over 25 km single mode fiber an electrical power of 0.9 mW and 18.1 mW was attained for the Raman amplifier and fiber optic parametric amplifier, respectively.

Performance Investigation of All-Optical NRZ-to-Manchester Format Conversion with SOA-MZI Based XOR Logic Gate

All-optical format conversion between non-return-to-zero (NRZ) and the Manchester code is implemented by using an optical exclusive-OR (XOR) logic gate based on a semiconductor optical amplifier Mach-Zehnder Interferometer (SOA-MZI). There is 10 Gbit/s all-optical NRZ-to-Manchester conversion implemented in our simulation system and BER performance of the format conversion is investigated. Transmission performances of the converted Manchester coded signal are discussed in terms of transmission length and received optical power.

Demodulating the Response of Optical Fibre Long-Period Gratings: Genetic Algorithm Approach

The extraction of the physical parameters of long period gratings from the spectral response is not an easy process. We present a demodulation technique to synthesize the physical parameters of a long period grating recorded in an optical fibre. The demodulation is achieved through the implementation of a genetic algorithm. The extracted parameters are in agreement with the typical values known for long period gratings.

Improvement of Amplitude-Shift-Keying Signal Quality by Employing an Effective Spectrum Equalization Method in a Combined FSK/ASK Modulation Scheme

A simple, economical and applicable spectrum equalization method is implemented by employing a reshaping filter in the combined frequency-shift-keying/amplitude-shift-keying modulation scheme to improve the quality of amplitude-shift-keying optical signal. The 3-dB improvement for eye diagram height is experimentally demonstrated.

Influence of channel power and pumping configuration on the gain profile of distributed Raman fibre amplifier

The influence of channel power and pumping configuration on the gain profile of a distributed Raman fibre amplifier has been experimentally measured. The experimental results show that the influence is significant and should be considered during the gain flatness optimization of the distributed Raman fibre amplifier.

An Optical Labeling Scheme with Novel DPSK/PPM Orthogonal Modulation

A novel differential-phase-shift-keying (DPSK)/pulse-position-modulation (PPM) orthogonal modulation is proposed for optical labeling applications, with PPM data as the high-speed payload and DPSK signal as the optical label. The systematic setup for the proposed scheme and research on bit-error rate is presented. The results show that at the bit-error rate of 10?9, the power penalties for 70 km fiber transmission are in the range of 1?3 dB to DPSK label and 5?6 dB to PPM payload in our simulation system. This is under the condition that the large extinction ratio of 18?19 dB is used for the intensity modulators of the PPM payload, with a well received DPSK label. Thus the feasibility of the proposed scheme for all optical transmission networks is clearly verified.