FIBER-OPTIC COMPENSATION FOR DISPERSION, GAIN TILT, AND BAND PUMP NONLINEARITY

摘要

An apparatus and method are described for combining optical amplification and dispersion compensation in a Raman amplifier (Fig. 4a). Dispersion-Managing Raman Amplifier (DMRA) (Fig. 4a) combines Raman amplification with dispersion compensation by selecting the length and dispersion of the gain fiber (100) to balance the dispersion of the link. The pumping level is adjusted to balance the losses from the gain fiber (100) and transmission link (130). For WDM transmission systems based on dispersion-shifted fiber (DSF), operation in the "violet band" between 1430-1530 nm is based on Raman amplification. By using a DMRA (550), a dispersion (510) and nonlinearity managed system can be implemented. Furthermore, gain equalization can be added to the DMRA by cascading one or two Mach-Zehnder frequency filters. The invention also includes a method for symmetrically adding channels below and above the C-band, the gain tilt within the C-band can be minimized. To minimize the interaction between pumps for different bands (Fig. 16d), alternate band pumps can be spatially dispersed and/or cross-polarized (Fig. 16d).