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 […]
One of the questions we get asked now and then is on the connector life in our ONT products. Pluggable optical modules can be plugged in and out of our test sets, both as part of their test and validation but also in normal applications engineers will plug in and out different optical interfaces in […]
With the advent of 400G Ethernet, it has become critically important to fully understand and validate Forward Error Correction (FEC) logic and the related software and firmware. 400G Ethernet uses PAM-4 signalling optically and electrically. Because of the susceptibility to the impact of noise, distortion, and other disturbances, most links will run with a raw error […]
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 […]
With the emergence of 400G Ethernet we have seen the wide deployment of higher order modulation in client interfaces. We have moved from the mature NRZ of 100G and below to PAM-4 modulation both optically and electrically. This has allowed 400G links to be deployed for reaches of 10km. But what about applications like data […]
This is the first in a series of blog posts that offer technical and industry insights from Dr. Paul Brooks, who has been involved in R&D and product management for high speed electronic and photonic test equipment for over 20 years. Dr. Brooks holds several patents related to measurement in high speed test equipment and […]
