SC460 - Digital Coherent Optical System Performance Basics
Sunday, 03 March
09:00 - 12:00
Short Course Level: Beginner and Advanced Beginner
Maurice O'Sullivan; Ciena, Canada
John Cartledge; Queen's University, Kingston, Canada
Short Course Description:
Coherent optical fiber transmission is a commercial solution which supports capacity growth in reconfigurable WDM networks at bit rates of 40 Gb/s and higher. Its implementation follows on available CMOS technology that is capable of digital signal processing (DSP) capacities of multiple terabits per second and co-integration with analog-to-digital (ADC) and digital-to-analog (DAC) conversion, as well as forward error correction (FEC) coding. This course is designed to equip participants with an understanding of the metrics used to assess the performance of coherent optical fiber transmission systems, and the ability to estimate and compare link performance in practical coherent transmission applications including nonlinear WDM propagation. Where possible, analytic approximations are used to estimate transceiver performance.
Brief review of DSP assisted electric field modulation and coherent detection
Metrics for characterizing transceiver performance:
- optical signal-to-noise ratio,
- linear and nonlinear noise,
- electrical signal-to-noise ratio,
- pre FEC bit error ratio (pre-FEC-BER),
- Q-factor corresponding to pre-FEC-BER,
- minimum distance Q-factor corresponding to pre-FEC-BER,
- error-vector magnitude,
- mutual information, and
- generalized mutual information
link noise-to-signal-ratio (NSR) budget approximation
Bit interleaved coded modulation (BICM) primer
NSR budget approximation applied to non-ideal weakly nonlinear systems (with worked examples)
Short Course Benefits:
This course should enable you to:
Understand basic coherent systems and standard implementations of electric field transmitters and coherent receivers
Understand the different mechanisms that impact transceiver performance
Estimate transceiver performance for basic modulation formats
Determine approximate trade-offs between spectral efficiency, baud, reach and capacity
Perform link design and budgeting for WDM systems based on approximate mathematical descriptions
Short Course Audience:
This course is intended for familiars of standard optical transmission who are interested in the workings and estimates of performance of commercial coherent solutions in multi-span amplified WDM systems.
For more than 25 years, Maurice O'Sullivan has contributed to the design and manufacture of optical fiber and, mostly, the highest capacity long line transmission equipment of its day with emphasis on layer 0. He holds a PhD in Physics from the University of Toronto.
For more than 35 years, John Cartledge has conducted research on optical fiber communication systems. He holds a PhD in Applied Mathematics from Queen’s University.