Despite the presence of finite differential group delay leading to polarization mode dispersion (PMD), pulse narrowing occurs in fibers when polarization-dependent loss (PDL) is also present. PMD and PDL in fiber may lead to interference during pulse propagation, in turn reducing the width of propagating pulses. This reduction depends in addition on the state of polarization in which the input light is launched. Equations representing the output power of the pulse are derived for different cases of input states of polarization in terms of PMD and PDL. The effective pulse width difference calculated from these equations indicates that the pulse narrowing is prominent for a PMD of 30 ps, a PDL of 3.5, and an input pulse width of 100 ps in different states of polarization for a PDL element sandwiched between two PMD elements. © 2007 Society of Photo-Optical Instrumentation Engineers.