Nonlinearity compensation in DWDM metro systems using optical phase conjugation

Abstract

Many studies have shown that the use of the optical phase conjugation (OPC) to perform dispersion and nonlinear compensation for high-speed fiber optic transmission systems is highly effective. Especially in backbone systems, the use of mid-link OPCsets has proved a clear advantage. When OPC is in the middle of the transmission line, it will immediately create a complex conjugate of the OPC forward signal (the signal is transmitted on the first half of the transmission line). This new signal will be transmitted on the second half of the transmission line, and therefore dispersion and nonlinear effect will be compensated. Recently, with the rapid increase in the demand for user traffic, the capacity of metro systems has also increased rapidly. Dense Wavelength Division Multiplexing (DWDM) metro systems have characteristics such as short transmission distances, multiple add/drop node numbers, multiple optical amplifiers (mostly Erbium Doped Fiber Amplifier (EDFA)); however, the optical signals in them are also greatly affected by the dispersion and nonlinear effects. In this paper, we examine the efficiency of using OPC for dispersion and nonlinear compensation for optical signals in DWDM metro systems. This will be very important in understanding applications of OPC in actual systems later.