The Optical Networking and Communication
Conference & Exhibition

San Diego Convention Center,
San Diego, California, USA

SC393 - Digital Signal Processing for Coherent Optical Systems

Sunday, 19 March
13:30 - 17:30

Short Course Level: Intermediate


Chris Fludger; Cisco Optical GmbH, Germany

Short Course Description:

Digital signal processing (DSP) has always been an intrinsic component of optical communications, albeit for simple modulation techniques, framing and coding. The development of high-speed ADCs and DACs, and the increase in data processing power of CMOS ICs has enabled the implementation of complex signal processing techniques for signal modulation and demodulation. Combined with revived interest in coherent detection, algorithms have been implemented to increase the channel capacity and compensate for network impairments such as chromatic dispersion and PMD.

This course gives a basic introduction to coherent transceivers and takes a more in-depth view of the DSP building blocks and their implementation in a high-speed ASIC.

Parallel filter structures in the time and frequency domain will be identified and compared. The constituent sub-blocks, such as signal shaping and CD compensation filters, polarisation compensation filters, frequency, carrier and clock recovery will be analysed. Complexity and implementation trade-offs will be discussed, along with their relative importance for different field applications.

Since the coherent receiver must compensate for the optical channel, estimation of parameters such as CD and PMD can be performed. Channel parameter estimation methods will be explained.

Techniques to enable flexible capacity and the implications for the network will be explained. In addition, the course will describe methods for performing non-linear compensation, their effectiveness and relative complexity.

Next generation coherent transceivers must be cost-effective, flexible, spectrally efficient and highly tolerant to impairments in the channel. This course explains the enabling technology, practical design aspects and future research.


Short Course Benefits:

This course should enable you to:

  • Describe the principle building blocks in a coherent optical transceiver.

  • Explain the function of frequency and time-domain filters and their advantages and disadvantages.

  • Explain the implementation of pulse shaping and CD filters.

  • Describe techniques for frequency and carrier phase estimation.

  • Summarize the importance of clock recovery and describe clock recovery methods.

  • Describe the components of polarization tracking filters.

  • Explain how channel parameter estimation may be performed in coherent transceivers.

  • Explain the options for achieving flexible capacity including implications for the network.

  • Quantify the effectiveness and complexity of non-linear compensation.

Short Course Audience:

This course is intended for individuals having an intermediate knowledge of digital lightwave transmission systems. It will be of value for industrial professionals (system designers, managers) who need to understand the different components in digital coherent transceivers, as well as for researchers who are new to the field.

Instructor Biography:

Chris Fludger has developed three generations of coherent optical transceivers at Cisco Optical GmbH (formally CoreOptics) where he specializes in System Design and Digital Signal Processing. He has received Master's and Doctorate degrees in electronic engineering from Cambridge University, UK. Previously, at Nortel Networks he has worked on electronic signal processing, advanced modulation techniques and Raman amplification.

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