How to measure the extinction ratio of fiber optic arrays

IEC 61280-2-2:2012 describes a test procedure to verify compliance with a predetermined waveform mask and to measure the eye pattern and waveform parameters such as rise time, fall time, modulation amplitude and extinction ratio. The PEM-400 is an instrument developed for high-volume testing of the polarization extinction ratio (PER) of polarization maintaining (PM) components such as fiber array units (FAU) and external laser small form-factor pluggables (ELSFP). It is defined as the ratio of the maximum to minimum optical power levels, typically expressed in decibels (dB). [pdf]