This procedure describes a method of measuring the repetitive temporal characteristics of a two-level, intensity-modulated optical waveform (eye pattern) at an optical interface point. From the measured eye pattern, waveform parameters such as rise time, fall time, overshoot, and extinction ratio can be extracted. Alternatively, the waveform can be tested for compliance with a predetermined waveform mask. The primary components of the measurement system are a photodetector, a low-pass filter, and an oscilloscope, as shown in figure 1.

The bandwidth and other characteristics of the low-pass filter depend on the application. Refer to product-specific documentation for the specification of the low-pass filter transfer function.