An chromatic dispersion monitoring method based on spectral-shift of SOA

Abstract

A remnant dispersion monitoring method based on spectral-shift of SOA in high speed optical communication system with CSRZ format and single channel speed of 40 Gbit/s is proposed. The system performance can be optimized by careful choosing bandwidth and center wavelength of the optical fiber grating filter. The dynamical monitoring range is ±60 ps/nm and the monitoring precision is about 5 ps/nm. This method can be suitable for the application in dynamical dispersion compensation of high speed optical communication systems.CLC numbers: TN292.11 Document code: A Article ID:Previous works on dispersion monitoring have resulted in the development of numerous approaches, for example, detecting the intensity modulating from a phase modulation [1,2] , modulating the frequency of the transmitted data signal and monitoring the clock deviation [3] , inserting in-band subcarriers [1] in the transmitter and monitoring their radio frequency tones [4,5] , adding an amplitude-modulated doublesideband subcarrier to the signal and measuring the phase delay between two subcarrier tones [6] , extracting the clock component and measuring its RF power [7] , and so on.In this paper, we propose a new and simple remnant dispersion monitoring method based on spectral shift effect of semiconductor optical amplifiers (SOAs). It is best suited for application in high speed optical communication system with single channel speed of 40 Gbit/s and CSRZ format.SOAs have received considerable investigation due to their excellent characteristics and potential use in optical communication systems [8] . The theory of pulse propagation in SOAs generally treats the amplifier as a two-level system. When the intra-band relaxation time in , the carriers in conduction band, is included, the solving of the problem become complex. Fortunately, in is generally about 0.1 ps in SOA, if suppose that the input pulses width p ps , solving of the problem becomes very simple. In our research, this condition is easily satisfied.