Dispersive effects monitoring for RZ data by adding a frequency-shifted carrier along the orthogonal polarization state

As optical systems approach high speed and long distances, dispersive effects [chromatic dispersion (CD) and polarization-mode dispersion (PMD)] can severely distort optical signals in the transmission link. It is important to dynamically monitor the dispersive effects in order to achieve high performance. We propose a method for dispersive effects monitoring by adding a frequency-shifted carrier along the orthogonal polarization and measuring the generated radio frequency (RF) clock power. Using this technique, PMD monitoring is isolated from CD effect and the CD information can be simultaneously obtained. We experimentally demonstrate this technique in a 10 Gb/s return-to-zero (RZ) system by adding an orthogonal frequency-shifted carrier using an acoustooptic (AO) shifter.