Parametric Signal Processing
Shu NamikiNational Institute of Advanced Industrial Science and Technology (AIST)
Network Photonics Research Center
Part of this work is supported by - Project for Developing Innovation Systems of the Ministry of Education, Culture,
Sports, Science and Technology (MEXT), Japan.
ECOC, 21 Sept. 2014WS2 - WHAT IS THE ROLE OF OPTICAL SIGNAL PROCESSING IN THE AGE OF DSP?
1
OSP vs DSP.. Nothing is trans-historical.., but fundamental physics.
• The old wisdom says, “Don’t fight with silicon!”– Digital coherent has obviated many of our good ol’ “cool” optical signal
processing topics at least in the 100G generation..– But, silicon is finally having difficulty in further scaling..
• How can optical signal processing be compelling to help silicon?– Be compatible with digital coherent signals– Help off-load DSPs and lower the entire cost– Be superior to O/E:E/O alternatives– Be capable of completely new functions
2 S. Namiki, ECOC2014, WS2, Cannes
Disp. Comp.
FEC
Others DBP+
Parametric signal processing• Compelling Features
• Plausible Applications
3 S. Namiki, ECOC2014, WS2, Cannes
Format agnostic
Low-noiseSeamless and wideband
Highly reliable Potentially compact
Multi-channel capable (Linear)Parametric amplifier including PSAWavelength converter / translatorUltrafast and Wideband Tunable dispersion and
delay compensator (P-TDC/PDDT)Optical phase conjugation for dispersion and
nonlinearity compensationAll optical samplingEtc.
Basically single-channel (Nonlinear)Optical regenerator, including phase
regenerator by PSAAll optical ADCClock recoveryEtc.
“Universal” All-Optical Wavelength Converter
Requirements for real systems Method
Format Independent
Phase Preserving FWM
Polarization Insensitive
PolarizationDiversity
Wideband(Seamless and Gridless) Dual-Stage
High conversion efficiency and low noise
SBS Suppressionby counter-
dithering
Ref: H. Nguyen Tan et al., in Proc. OFC, 2014, W3F.
Shared TunableTransponder
Degree 1
Degree 2
Degree 3
Degree 4
Wavelength cross connect(WXC)
WSS/Splitter
WSS/Coupler
WSS/Splitter
WSS/Splitter
WSS/Splitter
WSS/Coupler
WSS/Coupler
WSS/Coupler
Input fibers
Output fibers
TPAShared
Wavelength Converters
Flex-GridCDC-ROADM
Universal and Upgrade free!!
H. Nguyen Tan, et al., OFC2014 and OECC2014
NL + dispersion compensation by OPC
5 S. Namiki, ECOC2014, WS2, Cannes
Fundamental theory tells how they all be cancelled.“A” contains all the channels.𝜕𝜕𝐴𝐴
𝜕𝜕𝑧𝑧= −
𝛼𝛼2𝐴𝐴 −
𝑖𝑖2𝛽𝛽2𝜕𝜕2𝐴𝐴𝜕𝜕𝑡𝑡2
+16𝛽𝛽3𝜕𝜕3𝐴𝐴𝜕𝜕𝑡𝑡3
+𝑖𝑖𝛾𝛾𝐴𝐴 2𝐴𝐴
Nonlinear Schrödinger equation (NLSE)
𝜕𝜕𝐴𝐴∗
𝜕𝜕𝑧𝑧= −
𝛼𝛼2𝐴𝐴∗ +
𝑖𝑖2𝛽𝛽2𝜕𝜕2𝐴𝐴∗
𝜕𝜕𝑡𝑡2 +16𝛽𝛽3𝜕𝜕3𝐴𝐴∗
𝜕𝜕𝑡𝑡3 −𝑖𝑖𝛾𝛾𝐴𝐴∗ 2𝐴𝐴∗
Loss GVD TOD Kerr-effect
Befo
reO
PCAf
ter
OPC
1. OPC based on HNLF2. Distributed Raman Amplification (DRA)
To symmetrize power excursions3. Dispersion flattened fiber (NZDSF) [1]
To satisfy GVD and TOD requirements
λpump
λTx λRx
[1] N. Kumano et al., ECOC’02 PD1.4
Actually developed fiber [1]!
12 Gbaud 16QAM WDM transmission
w/o OPC
w OPC
10 dB NLT (nonlinear threshold) increase with 5.3 dB Q2 factor enhancement
~10 dB
~5.3 dB
24 km transmission
Experimental results
w/o OPC
w OPC
K. Solis-Trapala, OFC2014, W3F8, and, ECOC2014, We.2.5.4
This scheme can completely compensate the dispersion and nonlinearities of all the channels, including SPM, XPM, and FWM, all at once, while DBP can never do such.
“Physical back-propagation”
𝜕𝜕𝐴𝐴∗
𝜕𝜕𝑧𝑧= +
𝛼𝛼2𝐴𝐴∗ +
𝑖𝑖2𝛽𝛽2𝜕𝜕2𝐴𝐴∗
𝜕𝜕𝑡𝑡2 +16𝛽𝛽3𝜕𝜕3𝐴𝐴∗
𝜕𝜕𝑡𝑡3 −𝑖𝑖𝛾𝛾 𝐴𝐴∗ 2𝐴𝐴∗
𝜕𝜕𝐴𝐴∗
𝜕𝜕𝑧𝑧= +
𝛼𝛼2𝐴𝐴∗ +
𝑖𝑖2𝛽𝛽2𝜕𝜕2𝐴𝐴∗
𝜕𝜕𝑡𝑡2 −16𝛽𝛽3𝜕𝜕3𝐴𝐴∗
𝜕𝜕𝑡𝑡3 −𝑖𝑖𝛾𝛾𝐴𝐴∗ 2𝐴𝐴∗