XPM Induced Filter Free Multi-Wavelength Conversion Exploiting Hybrid Multiplexing Employing Sagnac Effect and Circulator in DWDM Networks

In this paper, XPM based filter free wavelength conversion is proposed and demonstrated using Sagnac interferometric loop, circulator, asymmetric Mach-Zehnder modulators and multiplexers. Two input NRZ signals of different wavelengths (1551 nm and 1553 nm) each with a data rate of 100 Gb/s are simultaneously converted to a target wavelength of 1555 nm. In contrast to other interferometry, using a common route where two light beams propagate in opposite directions, the Sagnac interferometer uses the interference created by superimposing light waves to extract information. Sagnac effect is exploited to isolate the wavelengths as a frequency selector and to provide phase shift between co- and counter propagating signals. Proposed system is investigated with or without using the optical band passes filters and compared with the back-to-back (b2b) signal. Simulation results reveals that filter less conversion obtained higher extinction ratio (> 20 dB) for both 1551 nm to 1553 nm and 1553 to 1555 nm conversion using Sagnac effect. Power penalties are found to be less than 0.5 dB for the conversion of 1551 nm to 1555 nm and less than 0.4 dB for the conversion of 1553 nm to 1555 nm. To the best of our knowledge, this is a novel technique that provides filter-free wavelength conversion, multicasting, and a reduction in system complexity without requiring separate phase control. Even at low power, the lack of filters lowers bit error rate and insertion losses. Filter-free wavelength conversion lowers complexity, increases scalability, and is more stable.