Kejian Guan

Theory of ultrahigh-speed clock extraction with phase lock loop based on a terahertz optical asymmetric demultiplexer

Abstract A novel ultrahigh-speed clock extraction scheme using optical phase lock loop based on a terahertz optical asymmetric demultiplexer (TOAD) is proposed and analyzed theoretically. It is shown that our proposed scheme can operate up to 1000 Gb/s and extremely low timing jitter can also be obtained (for the same loop noise bandwidth, the RMS timing jitter is only 1/17 of the FWM-type PLL at the bit rate 16×6.3 GHz Gb/s).

Comparison of the Performances of NRZ and RZ WDM Systems with Long Amplifier Spacing and Dispersion Compensation

The performances of NRZ and RZ in nonlinear WDM systems are compared by means of numerical simulation. Self-phase modulation, cross-phase modulation, group velocity dispersion, stimulated Raman scattering and other effects are included in our numerical model. The numerical results show that the performance of NRZ in the nonlinear WDM with dispersion compensation is better than that of RZ. The full dispersion compensation does not well improve the performance of RZ transmission in nonlinear WDM.

Theoretical analysis of an OTDM frame synchronization scheme

A novel OTDM frame synchronization scheme based on an electrical tank circuit incorporating an asymmetric nonlinear optical loop mirror (NOLM) as an optical nonlinearity is proposed and analyzed theoretically. This scheme is characterized by both the ultrahigh speed of the NOLM and the high reliability of the electrical tank circuit, and allows all channels to carry data.

The effects of channel separation, input power and cross-phase modulation on nonlinear WDM systems with dispersion compensation

This paper analyzes the effects of channel separation, cross-phase modulation and input power on nonlinear WDM systems with conventional single-mode fiber combined with dispersion-compensating fiber. The conclusions are: (i) The performance of different signal channels depends on the input power and the channel separation. (ii) In general, the shorter the channel separation, the shorter the maximum transmission distance; the larger the input power, the shorter the maximum transmission distance. (iii) Cross-phase modulation plays an important role on the performance of nonlinear WDM with DCF compensation.

A novel OTDM frame synchronization scheme based on a terahertz optical asymmetric demultiplexer with feedback

A novel optical time-division multiplexing frame synchronization scheme based on a terahertz optical asymmetric demultiplexer (TOAD) and an electrical clock extraction circuit with feedback is presented and simulated. This scheme is characterized by both the ultrahigh speed of a TOAD and the high clock fidelity of the electrical clock extraction circuit. The simulation shows that this scheme can perform frame synchronization very quickly, and a very low timing jitter can be obtained in the recovered frame clock.

Effects of different compensation configurations and ratios on a high speed lightwave system

Employing a dispersion compensation fiber, the effects of different compensation configurations and compensation ratios on the performance of high speed lightwave systems are numerically analyzed. The main results are: (i) with the same input power, full compensation and proper undercompensation, the maximum transmission distance can be obtained by employing postcompensation; (ii) the larger the input power, the shorter the dispersion compensation required, and the result is not related to compensation configurations; (iii) the best system performance can be obtained by employing proper undercompensation. Overcompensation and excessive undercompensation are not suitable for long distance transmission no matter how much the input power is and what the dispersion compensation configurations are.

A Novel Method of Transform Limited Optical Pulse Generation

A novel method to eliminate chirp of the gain switching distributed feedback laser-diodes (GS-DFB-LD) is presented, which the frequency chirp of the nonlinear effect of high power optical pulses in zero dispersion fiber (ZDF) is employed to eliminate the initial chirp of optical pulses.