Autocorrelation function for PMD emulators with rotators

Summary form only given. PMD emulators comprise a number of sections of high-birefringence fiber or waveplates connected by either polarization rotators or polarization controllers. With only one free parameter, rotators are more commonly used than polarization controllers. We present here a concise analytical expression for the autocorrelation function of a general n-section emulator with rotators. This expression yields results that are consistent with earlier numerical results. We then use this formula to demonstrate that it is possible to eliminate frequency-domain periodicity in the autocorrelation function by varying the lengths of the sections. This periodicity is not acceptable if emulators are to be used in WDM system studies.