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Fiber Optic Network Design

Fiber Optic Network Design. Class 8 C. S. Yan , X. Wu, M. Y. Li Dept. of Opt. Engr., ZJU 2013. Content. Introduction Development of optical fiber communication Bottlenecks Basic theory of COC Advantages, Principles, Structures and types DPSK DP-QPSK

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Fiber Optic Network Design

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  1. Fiber Optic Network Design Class 8 C. S. Yan, X. Wu, M. Y. Li Dept. of Opt. Engr., ZJU 2013

  2. Content • Introduction • Development of optical fiber communication • Bottlenecks • Basic theory of COC • Advantages, Principles, Structures and types • DPSK • DP-QPSK • Simulation of DPSK system by Optisystem • Pulse generation • Sequence decoder • Balanced receiver • Exercise today • Reference

  3. Introduction • Higher Spectral Efficiency • Higher Data Rates • Higher Receiving Sensitivity

  4. Introduction Development process on optical transmission rate and transmission distance product for thirty years bottlenecks Revolution? Moore's Law

  5. Introduction Development of optical fiber communication in the earlier years

  6. Introduction What is the bottlenecks for DWDM 1. Chromatic dispersion 2. polarization mode dispersion

  7. Introduction What is the bottlenecks for DWDM 3. Nonlinear effect 4. Electronic rate When >30GHz，limited by electronic circuit and ADC chip

  8. Introduction 4x 40Gb/s delayed S 1x 160Gb/s How to break through the bottlenecks ——Optical Time Domain Multiplexing (OTDM)? Electronic signals Optical signals

  9. Introduction The advantages of OTDM

  10. Introduction The Disadvantages of OTDM • High price • Ultra-narrow optical pulse laser • Optical clock extraction and de-multiplexing • Severe nonlinear effects

  11. Introduction 160Gb/s 160Gb/s 160Gb/s WDM multiplexerof Add-Drop OTDM add-drop 4 x 40Gb/s 40Gb/s 40Gb/s 4 x 40Gb/s 160Gb/s 4 x 40Gb/s WDM demultiplexer of Add-Drop OTDM demultiplexer 160Gb/s 4 x 40Gb/s OTDM multiplexers 160Gb/s 160Gb/s regenerated Combination of OTDM and WDM

  12. Basic theory of coherent optical communication How to breakthrough? COC? PhaseFrequencyPolarization Modulation Amplitude Modulation WDM OTDM Coherent Optical Communication

  13. Basic theory of coherent optical communication Opportunities come again COC • 2004, M. G. Taylor, PTL, Proposed to restore the signal using DSP, Digital coherent receiver technology • 2004, 20Gbit/s, QPSK system • solve the problem of channel attenuation • But hard to large scale Commercial • Replaced by EDFA in the 1990s 2002, R. A. Griffin (UK), DQPSK

  14. Basic theory of coherent optical communication Advantages of COC

  15. Basic theory of coherent optical communication The principle of COC

  16. Basic theory of coherent optical communication The principle of COC • Detector Responsivity • Optical power

  17. Basic theory of coherent optical communication The principle of COC

  18. Basic theory of coherent optical communication Structures and types of coherent receivers (Differential phase shift keying) (Quadrature Amplitude Modulation)

  19. Basic theory of coherent optical communication Signal Modulation of Differential phase shift keying (DPSK) •  phase change between 0 and 1 code

  20. Coherent demodulation process of DPSK Basic theory of coherent optical communication

  21. Basic theory of coherent optical communication Modulation formats comparison of coherent receivers 100Gbit/s OSNR=0.2dB 50GHz channel spacing

  22. Basic theory of coherent optical communication Modulation formats comparison of coherent receivers Dispersion can be compensated by DSP. For the same dispersion, it has different requirement for the computing power of the DSP (serials) After 1600km transmission in standard single-mode fiber

  23. Basic theory of coherent optical communication Coherent receiver of Dual-polarization quadrature phase shift keying (DP-QPSK) Balanced receiver Demodulation Polarization separation TIA: Trans-impedance amplifier Phase  intensity Optical  Electrical

  24. Basic theory of coherent optical communication 90 phase shift mixer of DP-QPSK Optical fiber type Free space type

  25. Basic theory of coherent optical communication 90 phase shift mixer of DP-QPSK LiNbO3 waveguide type Si-based monolithic integration Bell Lab 2010

  26. Basic theory of coherent optical communication 90 phase shift mixer of DP-QPSK Si-based monolithic integration type Furukawa InP-based monolithic integration type Bell Lab 2011

  27. Basic theory of coherent optical communication 90 phase shift mixer of DP-QPSK Major international manufacturers of 100Gbit / s coherent receiver

  28. Basic theory of coherent optical communication 90 phase shift mixer of DP-QPSK Physical map of InP based monolithically integrated coherent receiver by HHI and U2T

  29. DPSK—pulse generation Simulation of DPSK system by Optisystem software Constellation diagram

  30. M-ARY pulse generator and Threshold detector Simulation of DPSK system by Optisystem software input M-ary signal pulse position bit period linear gain duty cycle parameter Bias if the signal input has a value of -3.3, the output level will be -3, since -3.3 is between -3.5 and -1.5.

  31. DPSK—pulse generation and decoding Simulation of DPSK system by Optisystem software

  32. DPSK sequence decoder Simulation of DPSK system by Optisystem software The DPSK decoder will calculate the value of i from the phase difference between consecutive signals k and k-1:

  33. DPSK sequence decoder Simulation of DPSK system by Optisystem software Assuming ϕ=0, if bits per symbol (n) equals 2, and M=4, then the values for I and Q will be: Assuming ϕ=0, if bits per symbol (n) equals 3, and M=8, then the values for I and Q will be:

  34. Balanced receiver Simulation of DPSK system by Optisystem software

  35. Balanced receiver Simulation of DPSK system by Optisystem software Eliminate intensity noise, improve sensitivity

  36. Exercise today Set up and study the system

  37. Reference • 刘卫华. 用于100Gbit/s 相干通信的90°相移光混合器研究. 华中科技大学博士学位论文. 2012 • 王甲琛. 基于FPGA的DPSK调制解调技术的设计与实现. 西安电子科技大学硕士学位论文. 2010

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