Alternate FRFT structure in inline module in DWDM fiber optic communication system

Dense Wavelength-Division Multiplexing (DWDM) fiber optic communication system consists of multiple channels, each having a light carrier signal placed at distinct wavelengths. A DWDM system is designed to maximize the datarate-transmission length product. Bandwidth or the datarate of the system is incremented by accommodating more number of channels to be multiplexed by reducing the spacing between the channels. The resulting narrow spacing between carrier wavelengths introduces linear and nonlinear distortions in the communication channel. An inline module is implemented in the optical domain to mitigate the linear and nonlinear distortions considered together. The module design is based on the Fractional Fourier Transform (FRFT). The application of FRFT on the optical signal causes it to transform into an intermediary domain in which the effects of both linear and non-linear distortions combine together. We propose an alternate structure for the FRFT implementation. The proposed structure should retain the original profile of the optical signal after the transformation. The module is tested for the modulation technique of CS-RZ. The results show enhanced performance parameters for the channel with the inline module.