H. Avramopoulos, C. Bintjas, K. Yiannopoulos, M. Kalyvas,. N. Pleros, S. Sygletos, G. Theophilopoulos, K. Vlachos, K. Zoiros. Collaboration with. L. Occhi, L.
Optical TDM Devices and their Applications Hercules Avramopoulos Photonics Communications Research Laboratory Department of Electrical and Computer Engineering National Technical University of Athens Athens, Greece PCRL
Research Group H. Avramopoulos, C. Bintjas, K. Yiannopoulos, M. Kalyvas, N. Pleros, S. Sygletos, G. Theophilopoulos, K. Vlachos, K. Zoiros
Collaboration with L. Occhi, L. Schares, G. Guekos, ETH Zurich R. Khera, J. R. Taylor, Imperial College S. Hansmann, H. Scholl, W. Hunziker, R. Dall’ Ara, Opto Speed S.A. W. Miller, Wavetek Wandel and Goltermann
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High speed optical TDM: general aspects z
Channel rate increase looks inevitable: line card reduction-cost reduction, network management complexity reduction, spectral efficiency improvement
z
Transeiver/switching node applications: mux/demux, scrambling, encryption, rate reduction, buffering, routing
z
Transmission applications: signal regeneration, wavelength conversion
z
Ultra-high speed all-optical switches: to perform on-the-fly, bit-wise, data processing and node control PCRL
Overview High frequency, wide-band optical switches and applications z
Nonlinear Optical Loop Mirror / Sagnac Interferometer Switch
z
Terahertz Optical Asymmetric Demultiplexer
z
Ultrafast Nonlinear Interferometer
z
Mach-Zehnder Interferometer
A wide-band application: Optical error rate measurements z
20 Gbps Optical Boolean XOR
z
20 Gbps Regenerative Optical Buffer
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Nonlinear Optical Loop Mirror / Fiber Sagnac Switch DATA AND CLK
DATA CLK
n2 , L
L Pp ~ λ_________ Α n2
To switch
z
differential π-phase
z
Kerr nonlinearity
z
L ~ 1 km for Pp~ 1 W
z
or Es ~ 1 pJ, for 1 ps pulse
z
or Pave ~ 500 mW for 50% duty PCRL
Nonlinear Optical Loop Mirror / Fiber Sagnac Switch ADVANTAGES z Kerr effect, fs response z no pattern effect z high performance z λ, polarization signal isolation z Boolean algebra compliant
DISADVANTAGES z long => instability z high power needed z specialty fiber for high performance
APPLICATIONS Boolean logic z signal processing z demultiplexing z
regeneration z memories z pulse shaping/compression z
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NOLM…: DEMUX from 640 Gbps to 10 Gbps Ultra high frequency-narrow band Pseudorandom 640 Gbps signal
Demultiplexed 10 Gb/s signal
Input pulses (Pseudo and fixed pattern)
Output pulses (Pseudo and fixed pattern) after 92 Km
From T. Yamamoto, E. Yoshida, K. Tamura, K. Yonenaga, M. Nakazawa, IEEE Photon. Technol. Lett.12, 353, 2000
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TOAD / SLALOM / SOA-Assisted Sagnac Switch DATA AND CLK
SOA Δx z
differential phase due to carrier dynamics
z
δφ ~ α ln(Gl/Gr)
z
not limited by slow gain dynamics
z
100’s fJ switching energy for few ps pulses
φl
φr
phase
CLK
time
δ-phase/transmission
DATA
time
=> low power amps adequate PCRL
TOAD/SLALOM/SOA-Assisted Sagnac Switch ADVANTAGES z low switching power/energy z easy to build z can be integrated z Boolean compliance at lower rates z reduce pattern effect with gain transparency
DISADVANTAGES z carrier dynamic dependence z SOA noise z performance dependence on pattern effect z differential delay limits speed
APPLICATIONS z memories z Boolean logic z logic elements z signal processing z counters/adders z demultiplexing z regeneration PCRL
TOAD…: ALL-OPTICAL BINARY COUNTER Multi-gate experiment
Output with LSB on RHS and MSB (230, 30th bit) on LHS.
Binary count from 213 (RHS) to 229 (LHS)
From A.J. Poustie, K.J. Blow, A.E. Kelly and R.J. Manning, ECOC 1999.
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TOAD…: DEMUX from 8x80 Gbps to 10 Gbps, High frequency-narrow band
All eight WDM channels in one time slot
From S. Diez, R. Ludwig and H.G. Weber, Electron. Lett.34, 803, 1998
All eight TDM channels in one WDM channel
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Ultrafast Nonlinear Interferometer DATA PMF
SOA
DATA AND CLK
Polarizer PMF
CLK
z
single arm interferometer
z
differential phase due to carrier dynamics
z
not limited by slow gain dynamics
z
few fJ switching energy for few ps pulses => loss optimized circuits may avoid amps PCRL
Ultrafast Nonlinear Interferometer ADVANTAGES z low switching power/energy z fast, 100 Gbps logic z high frequency and super-broadband z easy to build and isolate signals z can be integrated z Boolean compliant up to 40 Gbps
DISADVANTAGES z carrier dynamic dependence z SOA noise z performance dependence on pattern effect z differential delay limits speed
APPLICATIONS Boolean logic z signal processing z demultiplexing z
regeneration z memories z
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UNI: 100 Gbps BITWISE LOGIC NL Signal in
Xtal
UNI
BRF
100 GHz Soliton Compression Source
BRF
polarizer Band-pass Filter
SLA isolator
E /O Mod.
50/50 splitter
EDFA
Switch out
Polarization Rotator Voltage
12.5 GHz Fiber Laser
Control in
PMT
Sampling Source 0
2
4
6
Oscilloscope
8
Time (ms)
CLOCK STREAM λ = 1545 nm 1 0 0 G b /s con tro l
100 Gb/s AND λ = 1545 nm
Voltage
Voltage
CONTROL STREAM λ = 1554 nm
0
2
4
6
8
100 Gb/s INVERT λ = 1545 nm
T im e (m s)
0
2
4
6
8
Time (ms)
From K.L. Hall and K.A. Rauschenbach, Optics Letters 23, 1271, 1998
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UNI: REGENERATION AT 40 Gbps High frequency-broad band
40 Gbps input data stream (pump) 40 Gbps input pulse stream (probe) 40 Gbps regenerated data stream
40 Gbps 231-1 data regeneration back-to-back regenerated data signal
From I.D. Phillips, A.D. Ellis, H.J. Thiele, R.J. Manning and A.E. Kelly, Electron. Lett. 34, 2340, 1998
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Mach-Zehnder Interferometer Switch CLK MMI
DATA
SOA1 MMI
MMI SOA2
CLK
MMI
z
hybrid/monolithic MZI integration
z
differential phase in SOA’s by time delay
z
can be made polarization insensitive
φl
φr
phase
MZI configured for demuxing
time
δ-phase/transmission
delay
z
filter
time
as low as 1 fJ switching energy PCRL
Mach-Zehnder Interferometer Switch ADVANTAGES z
low switching energy (1 fJ/pulse)
z
large input signal dynamic range
z
stable, polarization insensitive
z
high frequency and broad band
z
has been integrated
DISADVANTAGES z carrier dynamics dependence z SOA noise z performance dependence on pattern effect
APPLICATIONS demultiplexing z regeneration z
wavelength conversion z NRZ to RZ conversion z
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MZI…: DEMUX FROM 168 Gbps to 10 Gbps
Cross correlation of input pulses
Cross correlation of demultiplexed pulse
From S. Nakamura, Y. Ueno, K. Tajima, J. Sasaki, T. Sugimoto, T. Kato, T. Shimoda, M. Itoh, H. Hatakeyama, T. Tamanuki and T. Sasaki, IEEE Photon. Technol. Lett. 12, 425, 2000
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MZI…: 40 Gbps 3R Regeneration
BER measurements back-to back 3R at different wavelengths 3R at same wavelength
From S. Fischer, D. Dulk, E. Gamper, W. Vogt, E. Gini, H. Melchior, W. Hunziker, D. Nesset and A.D. Ellis, Electron. Lett. 35, 2047, 1999
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Wideband Application: All-Optical Error Rate Measurement PRINCIPLE OF OPERATION Transmitter • generates an optical PRBS with shift register and XOR Receiver
• extracts optical clock from incoming PRBS • optical clock drives identical reference PRBS generator • XOR compares reference PRBS with incoming PRBS • outcome bits are stored in error counter • error counter is a regenerative loop memory and bit sampler PCRL
All-Optical Error Rate Measurement Receiver
Transmitter
Pseudorandom Pattern Generator
Pseudorandom Pattern Generator
Linear Feedback Register with XOR
Linear Feedback Shift Register with XOR
Optical Power Supply Modules
XOR Comparator
Error Counter
XOR Optical Gate
Regenerative Loop Memory
Optical Gain Modules
Clock Recovery
Fiber Ring Laser
SOA-Assisted Optical Gate
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Optical PRBS Generator Pseudo-Random Data Pattern Generator Output Sequence n-stage Shift Register 1 1
1 2
m
m+1
n
Optical XOR
Clock PCRL
20 Gbps Boolean XOR
z
Address & Header Recognition
z
Decision & Comparator Circuits
z
Pattern Matching
z
Data Encoding & Encryption
z
Combined with an Optical Regenerative Buffer to implement a Pseudo Random Binary Sequence
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20 Gbps Boolean XOR A XOR B
Pattern A 11111111111111111111111111111111111111111
Pattern B
SOA-ASSISTED UNI GATE 10101010000000010101010111111110101010100
01010101111111101010101000000001010101011
20 GHz Clock
UNI experiment photograph
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20 Gbps Boolean XOR EDFA 1 50:50
UNI gate XOR circuit z Controls A and B write operation on Clock z bulk 1.5 mm SOA z 9 ps Controls & Clock z
EDFA 2
Doubler Pulse Generator
80:20 45o PBS
Signal Generator
LD2 10 GHz 9 ps, 1554.6 nm
MOD
Att.
SOA
x Att.
Truth Table: A B CLK X 0 0 1 0 0 1 1 1 1 0 1 1 1 1 1 0
LD1 10 GHz 9 ps, 1545.2 nm
70:30
CLK
ODL A Control A
70:30
Att. ODL B Control B PM Fiber S U
PBS
x 0
45
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20 Gbps Boolean XOR A=0, B=0
Pattern A
Logical A, B=0
Pattern B
A=0, Logical B
Logical A, Logical B PCRL
20 Gbps Boolean XOR RESULTS z
All Optical Boolean XOR on Pseudo Data Pattern at 20 Gbps
z
10 fJ switching Energy
z
30 ps switching window
z
Low Pattern Effect
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20 Gbps Regenerative Optical Buffer
z
z
z
z
Regenerative Memory built with Optical Shift Register (Fiber) and a UNI gate Combined with the XOR Gate can be used to Implement a Pseudo Random Binary Sequence Used for the Implementation of an Error Counter Circuit to Infer the Bit Error Rate Used for Optical Packet Storage/Regeneration
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20 Gbps Regenerative Optical Buffer Clock Output Memory Content after 7 Circulations
Input Load-Up Sequence
SOA-ASSISTED UNI GATE Control Loop Memory
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20 Gbps Regenerative Optical Buffer Data Packet Generator
LD1 10 GHz 9 ps, 1545.2 nm
Att.
EDFA 1 50:50 ODL 1
Signal Generator 2
Pulse Generator 2
PM Fiber
45 0
PBS
Doubler
MOD2
x
Pulse Generator 1
Signal Generator 1
MOD1
LD2 10 GHz 9 ps, 1554.6 nm
45 0
PM Fiber
Att.
SOA
70:30
x
U PBS
S
Memory’s loop
50:50
EDFA 2 ODL 2 Att.
UNI gate memory circuit z recirculating pattern written on Clock z
bulk 1.5 mm SOA z 9 ps Controls & Clock z
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20 Gbps Regenerative Optical Buffer Input packet
Stored packet
Input bit pattern Stored bit pattern
Other stored packets
40x packet regenerative recirculation
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20 Gbps Regenerative Optical Buffer RESULTS z
Capability to write & store variable length 20 Gbps data packets up to 20 Kbit
z
Storage energy 33 fJ/bit
z
Data packet regeneration for more than 42 times or 20 μs
z
30 ps switching window
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Optical Error Rate Measurements
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Conclusions we have: z different high speed all-optical switches/logic units z compliant with Boolean algebra to build optical logic circuits z some with low switching energy z proven subsystems to perform limited but not trivial functionality z a lead to applications as channel rates increase for the future we need: z effort towards logic module integration into optical cards z effort towards commercialization PCRL
References A.D. Ellis, D.M. Patrick, D. Flannery, R.J. Manning, D.A.O Davies and D.M. Spirit, J. Lightwave Technol 13, 761, 1995 z M.Eiselt, W. Pieper and H.G. Weber, J. Lightwave Technol 13, 2099, 1995 z J.P. Sokoloff, P.R. Prucnal, I. Glesk and M. Kane,IEEE Photon. Technol. Lett. 5, 787, 1993 z N.S. Patel, K.L. Hall and K.A. Rauschenbach, Optics Letters 21, 1466, 1996 z N.S. Patel, K.L. Hall and K.A. Rauschenbach, IEEE Photon. Technol. Lett. 8, 1695, 1996 z S. Nakamura, Y. Ueno and K. Tajima, IEEE Photon. Technol. Lett. 10, 1575, 1998 z S. Nakamura, Y. Ueno, K. Tajima J. Sasaki, T. Sugimoto, T. Kato, T. Shimoda, M. Itoh, H. Hatakeyama, T. Tamanuki and T. Sasaki, IEEE Photon. Technol. Lett. 12, 425, 2000 z D. Wolfson, A. Kloch, T. Fjelde, C. Janz, B. Dagens and M. Renaud, IEEE Photon. Technol. Lett. 12, 332, 2000 z T. Yamamoto, E. Yoshida and M. Nakazawa, Electron. Lett. 34, 1013, 1998 z S. Diez, R. Ludwig and H.G. Weber, Photon. Technol. Lett.11, 60, 1999 z S. Fischer, M. Dulk, E. Gamper, W. Vogt, E. Gini, H. Melchior, W. Hunziker, D. Nesset abd A.D. Ellis, Electron. Lett. 35, 2047, 1999 z T. Yamamoto, E. Yoshida, K. Tamura, K. Yonenaga, M. Nakazawa, IEEE Photon. Technol. Lett.12, 353, 2000 z A.J. Poustie, A.E. Kelly, R.J. Manning and K.J. Blow, ECOC 1999 z A.J. Poustie, K.J. Blow, A.E. Kelly and R.J. Manning, Opt.Commun. 154, 277, 1998 z T. Yamamoto, E. Yoshida, K. Tamura, K. Yonenaga and M. Nakazawa, Photon. Technol. Lett.12, 353, 2000 z K.L. Hall and K.A. Rauschenbach, Opt. Lett. 23, 1271, 1998 z I.D. Phillips, A.D. Ellis, H.J. Thiele, R.J. Manning and A.E. Kelly, Electron. Lett. 34, 2340, 1998 z Y. Ueno, S. Nakamura, H. Hatakeyama, T. Tamanuki, T. Sasaki and K. Tajima,ECOC 2000 z C. Bintjas, M. Kalyvas, G. Theofilopoulos, T. Stathopoulos, H. Avramopoulos, L. Occhi, L. Schares, G. Guekos, S. Hansmann and R. Dall’ Ara, IEEE Photon. Technol. Lett. 12, 834, 2000 z M. Kalyvas, C. Bintjas, K. Zoiros, T. Houbavlis, H. Avramopoulos, L. Occhi, L. Schares, G. Guekos, H. Hansmann and R. Dall’ Ara, Electron. Lett. 36, 1050, 2000 z
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