New Optical PAM-4 Standards - Tutorial Series on the 400G / PAM-4 Challenges – Part 2

Blog Post created by stmichel Employee on Mar 27, 2017

PAM-4, PAM4, tutorial, part 2, eye diagram


The disruptive switch to PAM-4 (or PAM4) signaling which is used in 400 Gb Ethernet, 64G Fibre Channel and other standards creates new questions.

It’s time to find answers with this new video tutorial series that provides quick insights.

The second tutorial covers the optical PAM-4 standards that are evolving right now and compares parallel fiber architectures with wavelength-division multiplex (WDM) setups.   

This video gives an overview about the new PAM-4 Ethernet and Fibre Channel standards.


The tutorial series on PAM-4 (PAM4) introduces the basic ideas behind PAM-4 modulation. The evolving optical and electrical standards using this modulation format will be reviewed. You’ll also find a practical example of typical Ethernet implementations. PAM-4 brings new test needs and test patterns as well as new test parameters such as transmitter. Dispersion eye closure for PAM-4 (TDECQ) will also be discussed in detail. Furthermore, transmitter and dispersion penalty (TDP) will be explained.

The tutorial series will also cover the additional complexity of clock recovery.

You will learn about the new key optical and electrical PAM-4 measurements for characterizing transmitter outputs. This includes retrieving parameters like the output waveform, the transmitter linearity, the signal to noise and distortion ratio (SNDR), symbol error ratio (BER and SER), eye symmetry mask width (ESMW) and different types of jitter.

Of course, new characterization measurements on PAM-4 receiver inputs will also be discussed. These comprise of stressed input and input linearity tests.