Signal Integrity at 1310 nm

Is measured across the optical spectrum as a function of the wavelength and it assumes a certain RF modulation frequency. As lower frequencies are more lenient, this does not matter much for plasmonic circuits with a flat response up to 145 GHz.

The extinction ratio is meaningless without the measurement of the modulation amplitude, indicating how much optical power is being switched on and off. It’s given in dBm.

Dynamic extinction ratio is measured at a specific operating point. It’s generally lower than the static that is more like a theoretical value given by the transmission spectrum. So the dynamic measurement takes the operating point into consideration.

Given a certain OMA, the dynamic ER indicates the difference in dB between the on and the off state, given ratio.

As the industry has transitioned from NRZ to PAM4, the eye closure metric had to be adapted from transmitter dispersion penalty (TDP) to transmitter dispersion eye closure (TDECQ). The additional Q stands for quarternary indicating the four levels in the PAM4 signal.

TDECQ of the transmitter is conveniently determined indirectly by measuring the SER on a sampling scope and is the ratio in dB between the transmitter and an ideal transmitter. The smaller the better.

And, do they look good?