Post on 22-Mar-2023
Outline
• Some history
• all-optical devices
• bit-serial processing
• regenerative memory
• packet receiver design
Optical Logic, the history
• Nonlinearity– Giant n
2
• Slow so go for parallel– SEED devices
• Problems with spatial crosstalk
– Ultrafast• Small nonlinearity
“The fourth quadrant”
ELECTRONICS PHOTONICS
ANALOGUE
DIGITAL
FDM:manipulation of modulated carriers(1950s)
Electronic digital processing:direct manipulation of bits
WDM:manipulation of modulated carriers
Optical digital processing:direct manipulation of bits
Why all-optical?
• Not speed– electronics is pushing 100GHz
• Scalable architecture– time of flight systems– bit serial computer (Colorado)
• New techniques– all-optical regenerator– use of RZ pulses
NOLM achievements
• Soliton switching
• all-optical demultiplexing
• add-drop multiplexers
• all-optical sampling oscilloscope
• all-optical regeneration
• re-configurable node
Key Properties
• Speed– all-fibre, ~100fs
– SOA, ~10ps
• Switching power/energy– all-fibre, 1W km
– SOA, 100fJ
• ResponseR=
12{1+ cos (Δ ϕ)}
Time of flight
• Design system taking c into account
• No static memory
• Bit rate can increase by integer multiples
• Virtual machines can be multiplexed
• Colorado computer– http://albert.colorado.edu/~straub/spoc/spoc.html
Feedback/forward
• Feedback– 100GHz, bit separation of 3mm
– allows re-use of gates
• Feedforward– needs more gates
– only differential time shifts
All-Optical Regenerator
data
modulated clock(regenerated data)
isolator
Erbiumamplifier
filter
clockout
data in
Clock laser Loop Mirror
old data out
Experimental details
• Two SOA based all-optical nonlinear gates (TOAD/SLALOM)– switching energy < 1pJ per pulse
• Wavelength switching - 1533nm/1551nm• Memory loop ~ 1000 bits• Stable for several hours
– ( >10 billion circulations)
• Thresholding operation possible
Threshold properties
0
0.2
0.4
0.6
0.8
1
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2Normalised phase shift (π radians)
Tra
nsm
issi
on
1235
Storage threshold - change by altering induced phase shift
Amplituderestoration
Upper - input data patternLower - stored data pattern
01001000Fixed
Variable
• Amplitude restoration of pulses above the memory storage threshold& well defined threshold level
2 ns
10100101
• Increasing induced phase shift produced by pulses lowersmemory threshold for same input pattern
Upper - input data patternLower - stored data pattern
2 ns
Optical Implementation
I/P O/P
I/P O/P
Switch I/P
Switch I/P
TOAD2
TOAD1
DFB#1 1552nm clock pulses
~10ps @ 1GHz
DFB#2 1534nm clock pulses
~12ps @ 1GHz
90:10 50:50 50:50
attenuator
EDFA#1 #3
#2monitor O/P
EA modulator
PRBS ‘initiate’ pulse
fibre delay
Optical delay line
Results
Experimental and Theoretical pulse sequences
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Time (ns)
Multiplexed PRNGs
0 200 400 600 800 1000 1200 1400 1600 1800 2000
-16.0
-18.0
-20.0
-22.0
-24.0
-26.0
-28.0
-30.0
Frequency (MHz)
Pow
er (d
Bm
)
-12.0
-14.0
-16.0
-18.0
-20.0
-22.0
-24.0
-26.0
-28.00 200 400 600 800 1000 1200 1400 1600 1800 2000
Frequency (MHz)
Pow
er (
dBm
){713,552} ≡ 23 × {31,24}
Corresponding to 23 temporally multiplexed 231-1 sequence generators
These can be synchronous or asynchronous
All-Optical Counting
. ... ..001 ..001
COUNT (m bit)
CARRY (m-1 bit)
m bit
INPUT
OUTPUT
.
clock
clock
m bit
XOR
AND
Experimental Implementation
TOAD1
Switch I/P
I/P O/P
TOAD2
Switch I/P
I/P O/P
TOAD3
Switch I/P
I/P O/P
TOAD4
Switch I/P
I/P O/P
EDFA
Opticaldelayline
50:50
50:50
90:10
COUNT Output
DFB#1
DFB#2
DFB#2
COUNT memory (297 bits)
CARRYmemory
(296 bits)
EAM
Input bitsto be counted
Fibredelay
XOR
AND
Electricaldata
Packet Receiver (b)
Packet
HEADERWINDOW
PAYLOAD
HEADER
ADDRESS
ONES WITH RESET
Sync
CORRECT HEADER
PacketPASS
EXTRACT
The future
• Integration is the key– integrated MZ interferometer
• HHI• ETH Zurich
• Single bit feedback– allows line rate bit serial processing
• Feed forward techniques– use more gates
BT Bit Serial Work
• All-optical circulating shift register using a semiconductor optical amplifier in a fibre loop mirror
– A. J. Poustie, R. J. Manning, and K. J. Blow, Electron. Lett., 32 1215 (1996)
• All-optical clock division using a semiconductor optical amplifier loop mirror with feedback
– R. J. Manning, A. J. Poustie, and K. J. Blow, Electron. Lett., 32 1504 (1996)
• Nonlinear loop mirrors with feedback and a slow nonlinearity– K. J. Blow, R.J. Manning and A. Poustie, Opt. Commun., 134 43 (1997)
• All-optical regenerative memory for long term data storage– A. J. Poustie, K. J. Blow and R. J. Manning, Opt. Commun., 140 184 (1997)
• Semiconductor Laser Amplifiers for Ultrafast All-Optical Signal Processing
– R. J. Manning, A. D. Ellis, A. Poustie and K. J. Blow, JOSA B, 14 3204 (1997)
• Storage threshold and amplitude restoration in an all-optical regenerative memory
– A. Poustie, K. J. Blow and R. J. Manning, Opt. Commum., 146 262 (1998)
• Model of longitudinal effects in semiconductor optical amplifiers in a nonlinear loop mirror configuration
– K. J. Blow, R. J. Manning and A. J. Poustie, Opt. Commun., 148 31 (1998)
• Wavelength dependence of switching contrast ratio of a semiconductor optical amplifier based nonlinear loop mirror
– R. J. Manning, A. E. Kelley, A. Poustie and K. J. Blow, to be published Electron. Lett.
• All-optical regenerative memory with full write/read capability– A. J. Poustie, A. E. Kelley, R. J. Manning, and K. J. Blow, submitted to Opt. Commun.
Optical Logic, the history
• Nonlinearity– Giant n
2
• Slow so go for parallel– SEED devices
• Problems with spatial crosstalk– Ultrafast
• Small nonlinearity
Optical Implementation
I/P O/P
I/P O/P
Switch I/P
Switch I/P
TOAD2
TOAD1
DFB#1 1552nm clock pulses
~10ps @ 1GHz
DFB#2 1534nm clock pulses
~12ps @ 1GHz
90:10 50:50 50:50
attenuator
EDFA#1 #3
#2monitor O/P
EA modulator
PRBS ‘initiate’ pulse
fibre delay
Optical delay line
Results
Experimental and Theoretical pulse sequences
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Time (ns)
Multiplexed PRNGs
0 200 400 600 800 1000 1200 1400 1600 1800 2000
-16.0
-18.0
-20.0
-22.0
-24.0
-26.0
-28.0
-30.0
Frequency (MHz)
Pow
er (d
Bm
)
-12.0
-14.0
-16.0
-18.0
-20.0
-22.0
-24.0
-26.0
-28.00 200 400 600 800 1000 1200 1400 1600 1800 2000
Frequency (MHz)
Pow
er (
dBm
)
{713,552} ≡ 23 × {31,24}
Corresponding to 23 temporally multiplexed 231-1 sequence generators
These can be synchronous or asynchronous
All-Optical Counting
. ... ..001 ..001
COUNT (m bit)
CARRY (m-1 bit)
m bit
INPUT
OUTPUT
.
clock
clock
m bit
XOR
AND
Experimental Implementation
TOAD1
Switch I/P
I/P O/P
TOAD2
Switch I/P
I/P O/P
TOAD3
Switch I/P
I/P O/P
TOAD4
Switch I/P
I/P O/P
EDFA
Opticaldelayline
50:50
50:50
90:10
COUNT Output
DFB#1
DFB#2
DFB#2
COUNT memory (297 bits)
CARRYmemory
(296 bits)
EAM
Input bitsto be counted
Fibredelay
XOR
AND
Electricaldata