Tutorial: polarization mode dispersion impairment in lightwave transmission systems

Fiber PMD can cause a variety of impairments in optical fiber transmission systems. First, a single digital transmission channel suffers impairment due to intersymbol interference (ISI). The ISI impairment is caused by the differential group delay (DGD) between the two pulses propagating in the fiber when the input polarization of the signal does not match the principal state of polarization of the fiber. The first-order PMD impairment caused by this effect can be expressed as a power penalty proportional to the square of the instantaneous DGD to bit-interval ratio and the dimensionless A-parameter that depends on the pulse shape, modulation format, and receiver characteristics such as the response of the electrical filter. We will discuss measurements, emulations and simulations of these penalties and the associated A-parameter.