The polarization- scrambling technique could be used not only to suppress the polarization- induced detrimental effects in a long- haul lightwave system, but also to monitor various polarization- related parameters. However, this technique could interact with polarization- mode dispersion ( PMD ) and polarization- dependent loss, and then cause timing jitters, irregular intensity modulations, and PMD- induced repolarization. This problem could be substantially reduced by using the optimized scrambling frequency of about 10 kHz. (C) 2008 Society of Photo- Optical Instrumentation Engineers.