UCLA Extension

Optical Communication Systems

This course deals with the many technical issues, possible solutions, and recent progress in the exciting area of high-capacity optical communications. Discussions center on various limitations and applications throughout the device, system, and network regime.

The optical fiber, with its low loss and THz bandwidth, provides enormous data capacity. Furthermore, there has been much excitement involving the simultaneous transmission of several independent channels, each located at a different wavelength. Such wavelength-division-multiplexing (WDM) provides dramatic increases in aggregate system capacity as well as wavelength-dependent network routing. Note that a key enabling technology has been the Erbium-doped fiber amplifier (EDFA), which can provide gain to many channels simultaneously. In fact, the data capacity growth in optical fiber has experienced revolutionary growth that is akin to Moore’s Law, and we can now discuss topics such as Tbit/s capacities over transoceanic distances as well as Gbit/s/user access networking. This course focuses on (1) basic operation of optical fiber communication systems, and (2) reconfigurable optical networking.

Complete Details

Basic optical system design, including signal, noise, and sensitivity, is addressed in the context of high-performance transmission. The device and systems advances in wavelength-division-multiplexing are described, focusing on potential gains and limitations. Additional topics include optical amplifiers, multi-channel systems, nonlinear effects, chromatic dispersion compensation, polarization mode dispersion, and different modulation/coding formats.

Physical-layer issues associated with dynamic and reconfigurable WDM networks also are covered. For instance, as point-to-point links become more sophisticated, systems must dynamically adapt to changing traffic conditions in order to avoid SNR degradation. This scenario erupts into a much greater challenge when channels originate at different locations, as is the case with add/drop multiplexers, reconfigurable cross-connects, passive optical networking for access, circuit-switched networking, and-eventually-optical label and packet switching. Dynamic channel degrading effects are identified, including crosstalk, channel power equalization, tunable management of dispersion and nonlinear effects, nonuniform EDFA gain, switching-related transients, and non-ideal wavelength conversion and routing. Issues that relate to the security of the optical network also are described, with emphasis on vulnerabilities that may lead to denial-of-service as well as eavesdropping.

This course enables participants to:

  • Describe the basic components in an optical system
  • Explain the operation of optical data generation, transmission, amplification, and detection
  • Evaluate signal-to-noise ratios and system power penalties
  • Define several degrading effects in high-speed optical fiber transmission
  • Design and analyze a viable optical transmission system and optical multi-user network
  • Understand the basic concepts of reconfigurable multi-wavelength optical networks
  • Identify key degrading physical issues for a future all-optical network

This course is intended for engineers interested in acquiring a working and project-oriented knowledge of an optical communication system, managers wanting a broad overview of the critical technologies and recent directions in optical communications, and educators desiring a firm understanding of the fundamental concepts with the goal of teaching a lecture or laboratory course in optical communications.

Prerequisites

Basic familiarity with optics, semiconductors, and digital modulation is helpful; however, all topics are explained from fundamental principles.

Course Materials

Lecture notes are distributed on the first day of the course. The notes are for participants only and are not for sale.

Coordinator and Lecturer

Alan E. Willner, PhD, Professor, Department of Electrical Engineering Systems, University of Southern California, Los Angeles. Professor Willner’s research is in high-capacity optical communications and wavelength-division multiplexed optical systems. Prior to joining the USC faculty, he was a postdoctoral member of the technical staff at AT&T Bell Laboratories and a member of technical staff at Bellcore. Professor Willner has received the NSF Presidential Faculty Fellows Award from the White House, Packard Foundation Fellowship, NSF National Young Investigator Award, Fulbright Foundation Senior Scholars Award, IEEE Lasers and Electro-Optics Society (LEOS) Distinguished Traveling Lecturer Award, USC University-Wide Award for Excellence in Teaching, Fellow of the IEEE, Fellow of the OSA, the Eddy Award for Best Technical Paper in Pennwell optics magazines, and the Armstrong Memorial Award. His professional activities have included President-Elect of the IEEE LEOS, Editor-in-Chief of the IEEE/OSA Journal of Lightwave Technology, Editor-in-Chief of the IEEE Journal of Selected Topics in Quantum Electronics, Co-Chair of the OSA Science and Engineering Council, General Co-Chair of the Conference on Lasers and Electro-Optics (CLEO), General Chair of the LEOS Annual Meeting Program, Program Co-Chair of the OSA Annual Meeting, and Steering and Program Committee Member of the Conference on Optical Fiber Communications (OFC). Professor Willner has 475 publications, including one book.

Course Program

Introduction

  • Historical Perspective
  • Current Research Issues
  • Industrial and Market Trends
  • Concerns of the Defense Industry
  • Value of Optical Communications
  • Basic Fiber, Amplifier, and WDM Properties
  • Point-to-Point and Multi-Point Optical Communications

Background

  • Fundamentals of Optics
  • Basic Semiconductors (Band Diagrams, Absorption and Emission)
  • Coherence
  • Lasers
  • Chirp
  • Photodetectors
  • Filters
  • Modulators
  • Couplers
  • Isolators

Optical Fiber

  • Wave Propagation
  • Multimode and Singlemode Fibers
  • Fiber Attenuation
  • Multimode Dispersion
  • Waveguide and Material Dispersion

Basic Optical Communications Link

  • Digital Systems
  • Transmitters
  • Receivers
  • Sources of Noise (Thermal and Shot)
  • Signal Bandwidth
  • Noise Bandwidth
  • Basic Modulation Formats (ASK, FSK, PSK and NRZ, RZ)
  • SNR and BER
  • Eye Diagrams
  • Intersymbol Interference
  • Crosstalk
  • Link Power Budget
  • Dispersion Limits
  • Basic Coherent Heterodyne Systems

Optical Amplifiers

  • Basic Block Diagram
  • Gain and Population Inversion
  • Amplified-Spontaneous-Emission Noise
  • Erbium-Doped Fiber Amplifier (EDFA)
  • Emission and Absorption Spectra
  • Gain Saturation
  • SNR
  • Amplifier Cascades
  • L-Band EDFAs
  • Semiconductor Optical Amplifier (SOA) and Its Dependencies
  • Raman Amplifiers
  • Transmission Applications
  • Network Applications

Wavelength Division Multiplexing (WDM)

  • High-Speed Electrical and Optical Time-Division-Multiplexing (TDM)
  • Multi-Wavelength and Wavelength-Tunable Components
  • Multi-Wavelength Transmission
  • Capacity Enhancement
  • Wavelength-Dependent Routing
  • EDFA Challenges in WDM Systems (Crosstalk and Gain Non-Uniformity)
  • Wavelength Drift and System Stability

Nonlinear Effects

  • Nonlinear Refractive Index
  • Stimulated Raman and Brillouin Scattering Effects
  • Self- and Cross-Phase Modulation
  • Four-Wave-Mixing
  • Phase Matching
  • Management of Chromatic Dispersion and Nonlinearities
  • Different Fiber Types

Optical Networks

  • Architectures and Topologies
  • Network Evolution
  • Optical Add/Drop Multiplexing
  • Optical Cross-Connects
  • Wavelength Re-Use
  • Dynamic Physical-Layer Changes
  • Network Monitoring
  • Tunable EDFA Gain Flattening
  • Channel Power Equalization
  • EDFA Gain Transients
  • Passive Optical Networks (PONs)

Dispersion Compensation

  • Dispersion Tolerance
  • Dispersion Compensating Fiber
  • Chirped Fiber Bragg Gratings
  • Dispersion Maps
  • System Drift in Accumulated Dispersion
  • Tunable Optical Dispersion Compensation Methods
  • Electronic Compensation
  • Forward-Error-Correction Codes
  • Optical Performance Monitoring of Chromatic Dispersion

Polarization Mode Dispersion (PMD)

  • Polarization Discussion
  • First-Order and Higher-Order PMD
  • Stochastic Nature
  • Temperature Dependence
  • System Degradation
  • PMD Emulation
  • PMD Monitoring
  • Optical PMD Compensation
  • Electronic PMD Compensation

Subcarrier Multiplexing (SCM)

  • Modulation and Demodulation
  • Analog (AM and FM)
  • Digital
  • Required Linearity of Components
  • Carrier-to-Noise Ratios
  • Intermodulation Distortions (Composite Second-Order and Triple Beat)
  • RF Fading
  • Cable Television
  • Applications of SCM (Antenna Remoting, Phased-Array Radar, Network Labels)

Optical Switching

  • Circuit Switching
  • Burst Switching
  • Packet Switching
  • Control and Management
  • Contention Resolution
  • Types of Headers
  • Header Recognition
  • Wavelength Conversion Techniques (CGM, CPM, FWM, DFG)
  • Buffers
  • Synchronization
  • Clock Distribution
  • 3R Regeneration
  • Types of Switches (Thermo-Optic, Lithium Niobate, MEMS, etc.)
  • SONET and ATM Protocols
  • Network Security

Solitons

  • Dispersion
  • Nonlinear Medium
  • Compensation of Effects
  • Required Pulse Power
  • Required Pulse Shape
  • Sources of Soliton Pulses
  • WDM Soliton Collisions
  • Design Guidelines

Advanced Topics

  • Trends in Coherent Optical Communications (DPSK)
  • Ultra-Long-Haul Undersea Systems
  • Spectral Efficiency and Modulation Formats
  • Directly-Modulated Systems
  • Nanotechnology
  • Optical Code-Division-Multiple-Access

For more information contact the Short Course Program Office:
shortcourses@uclaextension.edu | (310) 825-3344 | fax (310) 206-2815

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