Since the emergence of 400 Gigabit Ethernet (GbE) around 5 years ago, we have seen PAM-4 modulation replace NRZ on both optical and electrical interfaces. We now see a broad and healthy ecosystem building for 400 GbE, and even 800 GbE, using PAM-4 signaling. In fact, we are even seeing the first 100 Gb per […]
As module bitrates increased from 100Gbs so too did the complexity of the modules. Starting with DSP based signal conditioning and clock recovery and onwards to pluggable coherent optics, PAM-4 and CMIS. With this new level of complexity, we had to take a very different approach to module-to-pluggable optics development, debugging and validation. Specifically, the […]
Growing up in Castleisland, County Kerry, my family was lucky to know the famous journalist Con Houlihan. With his fantastic command of the written word he was often asked to advise on the progress of young student’s written English by concerned mothers. Con’s stock reply would normally be ‘Well, they are making all the right […]
Pluggable coherent optics are now being developed for 400G applications with two distinct streams emerging. One is high performance CFP2 based for 1000+km reach and multi-service applications and the other is QSFP-DD ZR (and perhaps OSFP) for DCI and metro Ethernet applications. Both streams present new challenges for test and measurement, not just to meet […]
