Short Courses

Coherent technology was traditionally used for long-haul and metro networks. However, over the years, this technology has been increasingly adopted for shorter reach applications, such as data-center interconnect (DCI) and 5G/6G front/backhaul, to overcome physical limitations of Intensity-Modulation/Direct-Detect (IM/DD) as those application demand higher bandwidth.

Current developments of interoperability standards like ITUs G.698.2 for 100G metro systems, OIF 400ZR, 800ZR, 1600ZR/ZR+ and IEEE 802.3ct, 802.3cw, 802.3dj projects for data center interconnects are discussed in addition to multiple multi-source organization (MSO) activities, such as OpenROADM, CableLabs, OpenZR and OpenXR. It will be explained how these standards can take advantage from test and measurement equipment.

In this course a detailed understanding of commonly used multi-level quadrature amplitude modulation (QAM) formats will be provided. The physical principles of the generation and detection of such signals will be discussed.

The characterization of coherent transmitter requires a reference receiver (optical modulation analyzer) with significant amount of digital signal processing (DSP) before assessing the transmitter signal quality. The steps of the signal processing will be discussed as well as the available parameters to describe the quality of the signals and systems.

On the other side, the characterization of a coherent receiver requires a reference transmitter generating stress patterns. Relationship between constellation impairments and system performance parameters like error vector magnitude (EVM), bit error ratio (BER), signal-to-noise ratio, and Q-factor is described. It is discussed how these impairments can be attributed to properties of the sub-components of a transceiver.

The course is accompanied by measurements on live signals which will allow attendees a hands-on experience on how to perform coherent transceivers testing for development and compliance.

By understanding the concepts, engineers and decision makers will get a profound knowledge base to decide for the best test strategy for their applications.

By the end of this course you will be able to

• Understand the difference between coherent and IM/DD technology
• Understand the fundamental measurements for QAM formats
• Comprehend the digital signal processing needed to generate and analyze coherent signals and how impairments influence the derived quality parameters
• Compare the quality of various transceivers through the use of test and measurement instruments
• Relate details of constellation diagrams to specific device and/or measurement system impairments, and identify the root causes of measurement degradation and uncertainty
• Get a fundamental understanding of the measurements required by the different multi-vendor interoperable standards

This short course is intended for engineers who start to work or already have basic experience in research, development, manufacturing and/or standardization of optical coherent technology. Attendees should be aware of basic concepts of optical transmission. Managers, as well as technical buyers will get a profound background in order to make optimal decision for their test and measurement needs. Students will extend their knowledge in optimal test concepts for fiber optical testing in the field of coherent technology.

Fabio Pittalà

Product Planner, Keysight Technologies

Fabio Pittalà has more than 10 years of experience in the field of high-speed optical communication and joined Keysight Technologies as Product Planner at the Broadband and Photonics – Center of Excellence in April 2022.

Before joining Keysight, he was a Principal Engineer with Huawei Technologies, covering a wide range of topics spanning from Research to Product Development and Standardization. He has been actively contributing to IEEE 802.3 and ITU-T SG15 on the development of optical interfaces for coherent systems.

He received a Doctoral Degree from the Technical University of Munich (TUM), and a Master of Science in Telecommunication Engineering from the Technical University of Denmark (DTU).

He authors and co-authors >50 conference and journal papers, >40 standard contributions and >10 international patents.

Michael Königsmann
Application Specialist, Keysight Technologies

Michael Königsmann joined Keysight Technologies (formerly Agilent Technologies/Hewlett Packard) in 1996 as an Application Engineer for RF/µWave products in the Electronic Test & Measurement Business.

He held various positions in Sales, Product Support and R&D before he joined the Networks and Data Centers Technical Marketing Team where he focuses on applications for Optical Modulation Analyzer and High-Speed Arbitrary Waveform Generator product portfolios in Coherent Optical Communication and Silicon Photonics applications

Michael studied Electrical Engineering, specializing in Communication Engineering and Microwave Technology. He holds a degree in Communication Engineering from the University of Applied Sciences and Arts in Dortmund.