Microwave Photonics Applications of Stimulated Brillouin Scattering Dr. Avi Zadok, School of...
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Transcript of Microwave Photonics Applications of Stimulated Brillouin Scattering Dr. Avi Zadok, School of...
Microwave Photonics Microwave Photonics Applications of Stimulated Applications of Stimulated
Brillouin ScatteringBrillouin Scattering
Dr. Avi ZadokDr. Avi Zadok, , School of Engineering, Bar-Ilan UniversitySchool of Engineering, Bar-Ilan University +972-3-5318882+972-3-5318882 [email protected]@eng.biu.ac.il www.eng.biu.ac.il/~zadoka/www.eng.biu.ac.il/~zadoka/
Together with: Together with: Prof. Moshe Tur, Prof. Avishay Eyal, Dr. Oded Raz, Elad Prof. Moshe Tur, Prof. Avishay Eyal, Dr. Oded Raz, Elad
Zilka, and Yair Peled, School of Electrical Engineering, Zilka, and Yair Peled, School of Electrical Engineering,
Tel-Aviv UniversityTel-Aviv University
BIU – UV workshop, 13-14/4/2010BIU – UV workshop, 13-14/4/2010 Dr. Avi ZadokDr. Avi Zadok 22
OutlineOutline Broadband Stimulated Brillouin Scattering Processes in Broadband Stimulated Brillouin Scattering Processes in
Optical FibersOptical Fibers
Variable (“slow light”) group delay of waveformsVariable (“slow light”) group delay of waveforms
Data pulsesData pulses
Analog, radar waveformsAnalog, radar waveforms
Single-sideband modulation formatSingle-sideband modulation format
Ultra-wideband noise-based transmissionUltra-wideband noise-based transmission
BIU – UV workshop, 13-14/4/2010BIU – UV workshop, 13-14/4/2010 Dr. Avi ZadokDr. Avi Zadok 33
Stimulated Brillouin Scattering Stimulated Brillouin Scattering
Strict phase matching conditions: Strict phase matching conditions: pp - - ss = = B B (~2(~211 GHz)11 GHz)
BIU – UV workshop, 13-14/4/2010BIU – UV workshop, 13-14/4/2010 Dr. Avi ZadokDr. Avi Zadok 44
Characteristics of SBSCharacteristics of SBS Low threshold in standard fibers (few mW)Low threshold in standard fibers (few mW) Simple and robustSimple and robust Detrimental effect in optical communication: restricts the Detrimental effect in optical communication: restricts the
transmitted powertransmitted power Gain coefficient is of Lorenzian lineshape: Gain coefficient is of Lorenzian lineshape:
Ultra-narrow linewidth for CW pump: ~ 30 MHz only!Ultra-narrow linewidth for CW pump: ~ 30 MHz only! Objective: utilize SBS for all-optical signal Objective: utilize SBS for all-optical signal
processingprocessing
2 2
0 0
1 21 2
p p
sBs p B B
g A g Ag
jj
BIU – UV workshop, 13-14/4/2010BIU – UV workshop, 13-14/4/2010 Dr. Avi ZadokDr. Avi Zadok 55
SBS with Broadened PumpSBS with Broadened Pump
SignalPump1p2p3p
BIU – UV workshop, 13-14/4/2010BIU – UV workshop, 13-14/4/2010 Dr. Avi ZadokDr. Avi Zadok 66
SBS with Broadened PumpSBS with Broadened Pump
Broadened Pump: Magnitude gain is proportional to Broadened Pump: Magnitude gain is proportional to the pump spectrumthe pump spectrum
Phase response related to the magnitude gain Phase response related to the magnitude gain through the Kramers – Kronig Relations:through the Kramers – Kronig Relations:
'
'
'Re'2Im
22
d
gg
s
s
Calculation of SBS response for arbitrary pumpCalculation of SBS response for arbitrary pump
BIU – UV workshop, 13-14/4/2010BIU – UV workshop, 13-14/4/2010 Dr. Avi ZadokDr. Avi Zadok 77
Pump Broadening Via Direct Pump Broadening Via Direct ModulationModulation
Shalom et. al, JQE, Vol. 34 pp. 1816-1824, 1998
Thermalchirp
Adiabaticchirp
BIU – UV workshop, 13-14/4/2010BIU – UV workshop, 13-14/4/2010 Dr. Avi ZadokDr. Avi Zadok 88
Pump spectrum measurementPump spectrum measurement
tiT
Ttiiti N
5.1
0
mod1
SimulationSimulation Heterodyne measurementHeterodyne measurement
ns320T
mA11i
mA6.12 tiN
Synthesized pumpSynthesized pump
Modulation:Modulation:
MHz20NB
mA800 i
BIU – UV workshop, 13-14/4/2010BIU – UV workshop, 13-14/4/2010 Dr. Avi ZadokDr. Avi Zadok 99
““Slow Light”Slow Light” Optically-controlled, variable group delayOptically-controlled, variable group delay Sharp phase delay variations, often Sharp phase delay variations, often
associated with narrow-band gain / absorptionassociated with narrow-band gain / absorption Control through non-linear interactionsControl through non-linear interactions
Spectral gain Spectral phase delay
BIU – UV workshop, 13-14/4/2010BIU – UV workshop, 13-14/4/2010 Dr. Avi ZadokDr. Avi Zadok 1010
Pump spectrum synthesisPump spectrum synthesis
-3 -2 -1 0 1 2 30
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Re
lativ
e g
ain
Normalized frequency offset-3 -2 -1 0 1 2 3
-1.5
-1
-0.5
0
0.5
1
1.5
Normalized frequency offset
Ph
ase
re
spo
nse
[arb
.]
gIm 2Re BpEg
Sharp spectral edges of pump spectrum: Sharp spectral edges of pump spectrum: enhancement of delay–bandwidth product.enhancement of delay–bandwidth product.
BIU – UV workshop, 13-14/4/2010BIU – UV workshop, 13-14/4/2010 Dr. Avi ZadokDr. Avi Zadok 1111
Measurement of SBS gain and Measurement of SBS gain and phase responsephase response
Optical BPF
EDFA
Tunable Laser SSB Modulator
Arbitrary Waveform Generator
EDFA
DSFNetwork Analyzer
Polarization Controller
Isolator
Variable Attenuator
Detector
Pump
Pump
Probe
Loayssa et. al, IEE Proc. Optoelectron., Vol. 148 pp. 143-148, 2001
BIU – UV workshop, 13-14/4/2010BIU – UV workshop, 13-14/4/2010 Dr. Avi ZadokDr. Avi Zadok 1212
SBS Slow and Fast LightSBS Slow and Fast Light SBS amplification accompanied by steep gradients of the SBS amplification accompanied by steep gradients of the
signal phase as a function of frequency – group delay signal phase as a function of frequency – group delay
-3 -2 -1 0 1 2 30
10
20
Ga
in [d
B]
-3 -2 -1 0 1 2 3-2
0
2Frequency offset [GHz]
Ph
ase
[ra
d]
BIU – UV workshop, 13-14/4/2010BIU – UV workshop, 13-14/4/2010 Dr. Avi ZadokDr. Avi Zadok 1313
Delay of Isolated PulsesDelay of Isolated Pulses SBS amplification accompanied by steep gradients of the SBS amplification accompanied by steep gradients of the
signal phase as a function of frequency – group delay signal phase as a function of frequency – group delay
A. Zadok et al., Opt. Express 14, 8498, 2006
BIU – UV workshop, 13-14/4/2010BIU – UV workshop, 13-14/4/2010 Dr. Avi ZadokDr. Avi Zadok 1414
Delay of 5Gb/s PRBS Delay of 5Gb/s PRBS Output NRZ eye diagram: Synthesized modulation, 22dBm, 120ps delay
First demonstration of high-rate PRBS delay using SBS
BER for 80, 100, 120ps delay: <10-9, 10-8, 410-6
Zadok et. al, Opt. Express, Vol. 14 pp. 8498-8505, 2006
BIU – UV workshop, 13-14/4/2010BIU – UV workshop, 13-14/4/2010 Dr. Avi ZadokDr. Avi Zadok 1515
5Gb/s PRBS: Delay Enhancement5Gb/s PRBS: Delay Enhancement
Synthesized pump modulation: 25-40% longer delays
6 7 8 9 10 11 12 130
20
40
60
80
100
120
140
PRBS signal power gain [dB]
Me
asu
red
PR
BS
de
lay
[pS
]SynthesizedMod.
Random Mod.
BIU – UV workshop, 13-14/4/2010BIU – UV workshop, 13-14/4/2010 Dr. Avi ZadokDr. Avi Zadok 1616
True Time Delay (TTD) in phased True Time Delay (TTD) in phased array antennasarray antennas
True TimeDelay
DD D DD D DD
Beam-stirring using variable delay between elements Beam-stirring using variable delay between elements Large bandwidth: group delay instead of phase delayLarge bandwidth: group delay instead of phase delay Low distortion necessaryLow distortion necessary
BIU – UV workshop, 13-14/4/2010BIU – UV workshop, 13-14/4/2010 Dr. Avi ZadokDr. Avi Zadok 1717
LFM “impulse response” metricsLFM “impulse response” metrics
PSLPSLMain lobeMain lobewidth ~ 1/Bwidth ~ 1/B
elsewhere
LFM
lobemain
LFM dhdh22
ISLR
BIU – UV workshop, 13-14/4/2010BIU – UV workshop, 13-14/4/2010 Dr. Avi ZadokDr. Avi Zadok 1818
Delay of LFM signalsDelay of LFM signals
10 15 20 25
100
200
300
SBS power gain [dB]
De
lay
[ps]
10 12 14 16 18 20 2250
100
150
SBS power gain [dB]
De
lay
[ps]
20km DSF20km DSF
3.5km HNLF:3.5km HNLF:
‘‘+’: VNA+’: VNA
‘‘’’: LFM: LFM
Zadok et. al, IEEE PTL, Vol. 19, pp. 462-464, 2007
0
sin sinNd N Nc c f
50 GHz system: ~ 10 elements, 90°
BIU – UV workshop, 13-14/4/2010BIU – UV workshop, 13-14/4/2010 Dr. Avi ZadokDr. Avi Zadok 1919
Measured impulse responseMeasured impulse response
-2 -1.5 -1 -0.5 0 0.5 1 1.5 2
x 10-5
-150
-100
-50
0Input pulse
[Sec]
[dB
]
-500 -250 0 250 500-5
-3
-1
1
RF frequency [MHz]
ph
ase
[ra
d]
-30 -20 -10 0 10 20 30-60
-40
-20
0
Time [ns]
Re
spo
nse
[dB
] μs20T
1GHzB
Pump power:Pump power:
20dBm20dBm
Width broad: <1%Width broad: <1%
PSL: < -26dBPSL: < -26dB
ISLR: > 21dBISLR: > 21dB
Delay: 230psDelay: 230ps
BIU – UV workshop, 13-14/4/2010BIU – UV workshop, 13-14/4/2010 Dr. Avi ZadokDr. Avi Zadok 2020
SSB modulation - noiseSSB modulation - noiseHeterodyne spectral measurement of LFM-modulated signal:Heterodyne spectral measurement of LFM-modulated signal:
One side band amplified by SBS. One side band amplified by SBS. No harmonicsNo harmonics. . NF ~ 150*. NF ~ 150*.
Pump offPump off
Pump onPump on
μs2T
1GHzB
Pump 20dBmPump 20dBm
-4 -3 -2 -1 0 1 2 3 4-110
-100
-90
-80
-70
-60
-50
Optical frequency Offset [GHz]
Pro
be p
ower
spe
ctra
l den
sity
[dB
]
NoiseNoise
*: Olsson et. al, JLT, Vol. 5
pp. 147-153, 1987
A. Zadok et al. J. Lightwave Technol. 25, 2168-2174 (2007)
BIU – UV workshop, 13-14/4/2010BIU – UV workshop, 13-14/4/2010 Dr. Avi ZadokDr. Avi Zadok 2121
Impulse response of SSB Impulse response of SSB modulated LFM signalmodulated LFM signal
-40 -30 -20 -10 0 10 20 30 40-60
-50
-40
-30
-20
-10
0Im
puls
e re
spon
se [d
B]
Time [ns]
Simulated noiseIdealMeasurement
BIU – UV workshop, 13-14/4/2010BIU – UV workshop, 13-14/4/2010 Dr. Avi ZadokDr. Avi Zadok 2222
Ultra-wideband waveform Ultra-wideband waveform generationgeneration
UWB impulse radio: several GHz-wide, no sine-wave UWB impulse radio: several GHz-wide, no sine-wave carriers, low power spectral densitycarriers, low power spectral density
Applications: indoor wireless communication, imaging Applications: indoor wireless communication, imaging systems, vehicular radar systems. systems, vehicular radar systems.
BIU – UV workshop, 13-14/4/2010BIU – UV workshop, 13-14/4/2010 Dr. Avi ZadokDr. Avi Zadok 2323
UWB noise-based communicationUWB noise-based communication
Slow-rate modulation of broadband noise with carefully Slow-rate modulation of broadband noise with carefully controlled power spectral densitycontrolled power spectral density
Alternative to tailored, short pulses.Alternative to tailored, short pulses.
BIU – UV workshop, 13-14/4/2010BIU – UV workshop, 13-14/4/2010 Dr. Avi ZadokDr. Avi Zadok 2424
Experimental resultsExperimental resultsBrillouin pump spectrum: Generated noise spectrum:
1.1 GHz bandwidth1.1 GHz bandwidth
Y. Peled, M. Tur and A. Zadok, Paper NTuC16, Nonlinear Photonics 2010
BIU – UV workshop, 13-14/4/2010BIU – UV workshop, 13-14/4/2010 Dr. Avi ZadokDr. Avi Zadok 2525
Experimental results Cntd.Experimental results Cntd.8 Mb/s transmission (no reference) Correlation properties
Q = 10Q = 10
Y. Peled, M. Tur and A. Zadok, Paper NTuC16, Nonlinear Photonics 2010
BIU – UV workshop, 13-14/4/2010BIU – UV workshop, 13-14/4/2010 Dr. Avi ZadokDr. Avi Zadok 2626
Experimental results Cntd.Experimental results Cntd.4 Mb/s transmission (with reference) Decoded waveform
Q = 5Q = 5
1 2 3 4 5-0.5
0
0.5
Time [micro-sec]1 2 3 4 5
-5
0
5
10
15
20
25
Time [micro-sec]
Y. Peled, M. Tur and A. Zadok, Paper NTuC16, Nonlinear Photonics 2010