Experimental comparison of mid-link spectral inversion and conventional DCF-based transmission in a DWDM system at 40Gbit/s

Abstract

In this paper, the performance of mid-link spectral inversion (MLSI)-based transmission is quantitatively compared to the performance for 'conventional' dispersion compensating fiber (DCF)-based transmission. Bit error rates (BER) are measured at optimized residual dispersion for all sixteen channels after 800km transmission in standard single mode fiber (SSMF). We show that for the MLSI-based configuration up to a decade of improvement in BER is obtained compared to the DCF based system. MLSI has the potential of lowering the cost of long haul transmission systems since instead of having multiple DCF modules per span only one spectral inverter is required for the whole transmission line. For spectral inversion, a polarization independent magnesium-oxide-doped periodically-poled lithium-niobate (MgO:PPLN) based subsystem was used.

Long-haul DWDM transmission systems employing optical phase conjugation

“…[47] Hence, for transmission systems using DCF for periodic chromatic dispersion compensation MI is not of significance. For transmission systems using OPC for dispersion compensation MI might impair the performance but results reported so far have not shown MI induced degradation [31], [40]. Since for high values of chromatic dispersion (e.g., SSMF) the impact of MI is decreased [3], we conjecture that for the SSMF fiber type the contribution of MI is relatively small.…”

“…Across the C-band, the noise figure of the EDFA/Raman amplifiers can vary resulting in a spectral dependent performance of the WDM channels [31], which would result in a performance difference between the OPC and the DCF-based configuration. In order to exclude this wavelength dependent noise figure and thereby wavelength dependent performance, the Q-factor of all 44 channels is assessed in the DCF-based configuration.…”