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
Class 8
C. S. Yan, X. Wu, M. Y. Li
Dept. of Opt. Engr., ZJU
2013
Content
Introduction
Introduction
Development process on optical transmission rate and transmission distance product for thirty years
bottlenecks
Revolution?
Moore's Law
Introduction
Development of optical fiber communication in the earlier years
Introduction
What is the bottlenecks for DWDM
1. Chromatic dispersion
2. polarization mode dispersion
Introduction
What is the bottlenecks for DWDM
3. Nonlinear effect
4. Electronic rate
When >30GHz，limited by electronic circuit and ADC chip
Introduction
4x
40Gb/s
delayed
S
1x 160Gb/s
How to break through the bottlenecks
——Optical Time Domain Multiplexing (OTDM)?
Electronic signals
Optical signals
Introduction
The advantages of OTDM
Introduction
The Disadvantages of OTDM
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
Basic theory of coherent optical communication
How to breakthrough?
COC?
PhaseFrequencyPolarization Modulation
Amplitude Modulation
WDM
OTDM
Coherent Optical Communication
Basic theory of coherent optical communication
Opportunities come again COC
2002, R. A. Griffin (UK), DQPSK
Basic theory of coherent optical communication
Advantages of COC
Basic theory of coherent optical communication
The principle of COC
Basic theory of coherent optical communication
The principle of COC
Basic theory of coherent optical communication
The principle of COC
Basic theory of coherent optical communication
Structures and types of coherent receivers
(Differential phase shift keying)
(Quadrature Amplitude Modulation)
Basic theory of coherent optical communication
Signal Modulation of Differential phase shift keying (DPSK)
Coherent demodulation process of DPSK
Basic theory of coherent optical communication
Basic theory of coherent optical communication
Modulation formats comparison of coherent receivers
100Gbit/s
OSNR=0.2dB
50GHz channel spacing
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
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
Basic theory of coherent optical communication
90 phase shift mixer of DP-QPSK
Optical fiber type
Free space type
Basic theory of coherent optical communication
90 phase shift mixer of DP-QPSK
LiNbO3 waveguide type
Si-based monolithic integration
Bell Lab 2010
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
Basic theory of coherent optical communication
90 phase shift mixer of DP-QPSK
Major international manufacturers of 100Gbit / s coherent receiver
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
Simulation of DPSK system by Optisystem software
Constellation
diagram
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.
Simulation of DPSK system by Optisystem software
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:
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:
Simulation of DPSK system by Optisystem software
Simulation of DPSK system by Optisystem software
Eliminate intensity noise, improve sensitivity
Exercise today
Set up and study the system
Reference