Injection Locked Oscillators Optoelectronic Applications E. Shumakher, J. Lasri, B. Sheinman, G....

Injection Locked Oscillators Injection Locked Oscillators Optoelectronic ApplicationsOptoelectronic Applications

E. Shumakher, J. Lasri, B. Sheinman, G. Eisenstein, D. RitterE. Shumakher, J. Lasri, B. Sheinman, G. Eisenstein, D. RitterElectrical Engineering Dept. TECHNIONElectrical Engineering Dept. TECHNION

Haifa ISRAELHaifa ISRAEL

Q1, ω1 Q2, ω2

1 1Q

Non-LinearGain

satV iVrV

BPF

nsV

nsV

2112 Non-Linear

Gain

satViV

rV

Delay Line

Delay Line

2

BPF

2Q

tx2

12 n

tx1

General ConceptGeneral Concept

Delay Line

nsV Non-LinearGain

tx

injVsatV iV

rV

0

BPF

Q

Single oscillatorSingle oscillator Interlocked oscillatorsInterlocked oscillators

Fundamental LockingFundamental Locking First formulated by R. Adler (1946)First formulated by R. Adler (1946)

Principal locking criteriaPrincipal locking criteria

Given a master oscillator,Given a master oscillator, coupled uni- coupled uni-

directionally to a slave oscillator directionally to a slave oscillator

withwith

Locking takes place within the locking rangeLocking takes place within the locking range

Harmonic LockingHarmonic Locking

Two possible configurationsTwo possible configurations Sub-harmonic injection locking :Sub-harmonic injection locking : Super-harmonic injection locking :Super-harmonic injection locking :

ConsequencesConsequences Injected signal does not satisfyInjected signal does not satisfy Lifetime is very short inside the oscillating loopLifetime is very short inside the oscillating loop Dynamics of the loop can not be alteredDynamics of the loop can not be altered

Locking requires mediation by a non-linearityLocking requires mediation by a non-linearity

Harmonics generation –Harmonics generation –

Mixing with harmonicsMixing with harmonics and and

creates a component at which locks the creates a component at which locks the slave oscillatorslave oscillator

Harmonic LockingHarmonic Locking

Unidirectional LockingUnidirectional Locking

Improved signal qualityImproved signal quality Superharmonic IL – further improvementSuperharmonic IL – further improvement

or or Synchronization – Timing extractionSynchronization – Timing extraction Harmonic IL – Multirate timing extractionHarmonic IL – Multirate timing extraction

33rdrd Harmonic Unidirectional Locking Harmonic Unidirectional Locking

Coupled oscillators : Coupled oscillators :

11stst harmonic of harmonic of QQ22 exhibits a lower noise than the 1 exhibits a lower noise than the 1stst harmonic of the harmonic of the

higher quality injected signal byhigher quality injected signal by

Explainable through correlated noise considerationsExplainable through correlated noise considerations

10 2 10 3 10 4 10 5 10 6 10 7-120

-100

-80

-60

-40

-20 11stst QQ22 free free

33rdrd QQ22 free free 11stst QQ22 locked locked

33rdrd QQ22 locked locked

11stst QQ11Delay Line

nsV Non-LinearGain

tx1

satV iVrV

1

BPF

1Q

Delay Line

nsVNon-Linear

Gain

tx2

satViV

rV

2

BPF

2Q

21

Offset Frequency Hz

Pha

se N

oise

dBc

Hz

33rdrd Harmonic Unidirectional Locking Harmonic Unidirectional Locking

1 2 3 4 5 6 71 2 3 4 5 6 71 2 3 4 5 6 71 2 3 4 5 6 71 2 3 4 5 6 71 2 3 4 5 6 71 2 3 4 5 6 71 2 3 4 5 6 71 2 3 4 5 6 71 2 3 4 5 6 7

1 2 3 4 5 6 7

Initially uncorrelated signalsSignals turn into correlatedCorrelated signals

1st harmonics of Q1 at

1st – 4th harmonics of Q2 at ω2

1 2 3 4 5 6 7

Unidirectional Coupling ExperimentUnidirectional Coupling Experiment

Injected frequency is followed by the corresponding harmonicsInjected frequency is followed by the corresponding harmonics

Bias-T

Bias-TCV

DirectionalCoupler

Agilent Spec. Anal. E4446ABPF

Photo-HBT

EDFA

LNA

OpticalFilter

BV Low NoiseAmplifier

CW Laser Optical IsolatorPolarization Controller

Anritsu Synth. 68347C

Mach-Z

enderM

udulator

2

102

106

103

104

105

-140

-120

-100

-80

-60

-40 11stst QQ22 free free 11stst QQ11 injected injected 11stst QQ22 locked locked 33rdrd QQ22 locked locked

23

Offset Frequency Hz

Pha

se N

oise

dBc

Hz

33rdrd harmonics IL harmonics IL: : 11stst harmonics IL harmonics IL: :

Unidirectional Coupling Multi Rate Unidirectional Coupling Multi Rate Timing ExtractionTiming Extraction

Transmitter

Detector andAmplifier

Clock RecoveryRe-Timing

DecisionRe-Shaping

Output

Reciever

Multi Rate Timing ExtractionMulti Rate Timing Extraction

10 20 30 40

BV

Bias-T

Bias-T

CV

DirectionalCoupler

0

BPF

Photo-HBT

Frequency GHz

RZ signal or

optically processed NRZ

signal

GHz100

Extracted electrical clock

Lasri et. al 2002Lasri et. al 2002

Modulated RZ signal toward the photo – HBT based oscillator

Transmitter SchematicTransmitter Schematic

10 Gb/s – 40 Gb/sMultiplexer

Mod.

Data OutPhase shifter

DBR

~

Pulse compression

BERTransmitter

(231-1 @ 10 Gb/s)

40 Gbit/s

10 Gbit/s10 GHz

1010 Gb/s and 40 Gb/s modulated RZ signalsGb/s and 40 Gb/s modulated RZ signals


BV

Bias-T

Bia

s-T CV

DirectionalCoupler

Photo-HBT

0

BPF

Agilent PSA E4446A

DirectionalCoupler

CouplerVariable

Attenuator

IncomingRZ stream

ReceiverBERReceiver

DataIn

ClockIn

Recovered ClockRecovered Clock

Clock recovery of RZ data by direct Clock recovery of RZ data by direct optical IL of Photo-HBT based oscillatoroptical IL of Photo-HBT based oscillator

GHzorGHz 40410 00 Lasri et. al 2002Lasri et. al 2002

Det

ecte

d P

ower

dB

m

9.9998 10.0004 10.0012

-70

-60

-40

-20

0 injected signal

10.0002 10.0006 10.001

Free running

signal

Injection locked signal

-70

-60

-40

-20

0

4th harmonic

signal

injected signal

Injection locked

signal

-70

-60

-50

-40

-70

-60

-50

-40

10 kHz/div

40

40

1010 GHz LockingGHz Locking

Frequency GHz

Clock Recovery ResultsClock Recovery Results

4040 GHz LockingGHz Locking

Frequency GHz

Det

ecte

d P

ower

dB

m10 kHz/div


-26 -25 -24 -23 -22 -21 -20 -19 -18

-9

-7

-5

-3

-1

Optical Power dBm

Log

( B

ER

)Direct Clock

Recovered Clock

BER performance for 10 BER performance for 10 GHzGHz Locking Locking


33rdrd Harmonic Bidirectional Locking Harmonic Bidirectional Locking

Coupled oscillators :Coupled oscillators : Injections strength is inversely relative to the quality factorInjections strength is inversely relative to the quality factor

1 1Q

Non-LinearGain

satV iVrV

BPF

nsV

nsV

2112 Non-Linear

Gain

satViV

rV

Delay Line

Delay Line

2

BPF

2Q

tx2

12 n

tx1

21

1121

1

1111

1

11 1 x

Qy

QxxF

Qx

1111 xQy

12

2212

2

2222

2

22 1 x

Qy

QxxF

Qx

2222 xQy

Generalized Van der PolGeneralized Van der Pol

33rdrd Harmonic Bidirectional Locking Harmonic Bidirectional Locking

0.1 1 10 100-95

-90

-85

-80

-75

-70

-65

Injection Ratio P2 / P1

Pha

se N

oise

dBc

Hz 11stst QQ2 2 freefree

11stst QQ1 1 freefree

25:125:1

10:110:1

7:17:1 5:15:1 2:12:1

1.5:11.5:1

1:11:1

1:1.51:1.5

1:21:2

1:51:5

102 103 104 105 106 107-120

-100

-80

-60

-40

-20 11stst QQ11 free free 33rdrd QQ11 free free

11stst QQ22 free free 33rdrd QQ22 free free

free

102 103 104 105 106 107-120

-100

-80

-60

-40

-20 11stst QQ11 lock lock 33rdrd QQ11 lock lock

11stst QQ22 lock lock 33rdrd QQ2 2 locklock

1:51:2

102 103 104 105 106 107-120

-100

-80

-60

-40

-20

102 103 104 105 106 107-120

-100

-80

-60

-40

-20

1:1.5

102 103 104 105 106 107-120

-100

-80

-60

-40

-20

1:11.5:1

102 103 104 105 106 107-120

-100

-80

-60

-40

-20

102 103 104 105 106 107-120

-100

-80

-60

-40

-20

2:1

102 103 104 105 106 107-120

-100

-80

-60

-40

-20

5:1

102 103 104 105 106 107-120

-100

-80

-60

-40

-20

7:1

102 103 104 105 106 107-120

-100

-80

-60

-40

-20

10:1

102 103 104 105 106 107-120

-100

-80

-60

-40

-20

25:1

Offset Frequency Hz

Phase noise at offsetPhase noise at offset Power Spectral DensityPower Spectral Density

Bidirectional CouplingBidirectional CouplingExperimental SetupExperimental Setup

EDFA

PowerAmplifier

BV

Bias-T

Bias-T

CV

DirectionalCoupler

Agilent PSA E4446A

DirectionalCoupler

2

BPF

1

BPF

kmL fiber 3

Photo-HBT

Loop 1

Loop 2

OpticalFilter

CW Laser Optical IsolatorPolarization Controller

Mach-ZenderModulator

Bidirectional CouplingBidirectional CouplingExperimental ResultsExperimental Results

102 103 104 105 106-140

-120

-100

-80

-60

-40

-20 11stst QQ22 free free

11stst QQ11 free free

11stst QQ11 locked locked 33rdrd QQ22 locked locked 11stst QQ22 locked locked

102 103 104 105 106

11stst QQ22 free free 11stst QQ11 free free

11stst QQ11 locked locked 33rdrd QQ22 locked locked 11stst QQ22 locked locked

Offset Frequency Hz

Pha

se N

oise

dBc

Hz

Offset Frequency Hz

33rdrd harmonics IL harmonics IL: : 11stst harmonics IL harmonics IL: :

Ultra Low Jitter Pulse SourcesUltra Low Jitter Pulse Sources

RFAmplifier

0

RF BPF

CW Laser

DirectionalCoupler

PD

RF Signal

SOAPolarization Controller

Coupler

Optical Pulses

Active mode-locking of fiber/diode lasers :Active mode-locking of fiber/diode lasers : Clark et al. ( NRL Labs ) : Clark et al. ( NRL Labs ) : Ng et al. ( HRL Labs ) : Ng et al. ( HRL Labs ) : Jiang et al. ( MIT ) :Jiang et al. ( MIT ) :

In all cases, ultra low phase-noise microwave source employedIn all cases, ultra low phase-noise microwave source employed Self starting approach – Coupled OEO’s ( Yao and Maleki ) :Self starting approach – Coupled OEO’s ( Yao and Maleki ) :

GHzatMHzHzSf 1011009 GHzatkHzHzSf 1010010016 GHzatMHzHzSf 9101047

PowerAmplifier

DCI

Bias-T

Laser Diode

AR

laserL

FBG


kmL fiber 10

OpticalFilter

EDFA

Self-Starting Ultra Low Jitter Optical Self-Starting Ultra Low Jitter Optical Pulse SourcePulse Source

10 GHz 10 GHz RF signalRF signal

10 GHz optical pulse-train10 GHz optical pulse-train

BV

Bias-T

Bias-T

CV

DirectionalCoupler

Agilent PSA E4446A

DirectionalCoupler

0

BPF

Photo-HBT

Actively mode-locked diode laserActively mode-locked diode laser Photo-HBT based oscillatorPhoto-HBT based oscillator Extended cavity optoelectronic oscillatorExtended cavity optoelectronic oscillator

Bidirectional Coupling Pulse Source Bidirectional Coupling Pulse Source Experimental Setup Experimental Setup

PowerAmplifier

BV

Bias-T

Bias-T

CV

DirectionalCoupler

Agilent PSA E4446A

DirectionalCoupler

2

BPF

1

BPF

kmL fiber 10

Photo-HBT

Loop 1

Loop 2

OpticalFilter

DCI

Bias-T

Laser Diode

AR

laserL

FBGEDFA

Bidirectional Coupling Pulsed SourceBidirectional Coupling Pulsed SourceExperimental ResultsExperimental Results

Pulsed SourcePulsed Source Mode locked diode laserMode locked diode laser Modulated at it’s 6Modulated at it’s 6thth

harmonics ( )harmonics ( ) Driven by 3Driven by 3rdrd harmonics harmonics

of the EO ( of the EO ( ) ) Repetition rateRepetition rate Resulting locked signal Resulting locked signal

has better phase noise has better phase noise then the free running then the free running OEO OEO

-140

102 103 104 105 106

-120

-100

-80

-60

-40 11stst QQ22 free free 11stst QQ11 free free 11stst QQ22 locked locked 33rdrd QQ22 locked locked

Offset Frequency Hz

Pha

se N

oise

dBc

Hz

Electrical SignalElectrical Signal

10 GHz5 kHz/div

Pow

er d

Bm

-85

-75

-65

-55

-45

-35

-25

-15

-5

Closed loop

Open loop

0.05

0.15

0.25

0.35

1542.5 1543 1543.5 1544 1544.5

0.05

0.15

0.25

0.35

Wavelength nm

Open Loop

Closed Loop

1543.51542.5 1543 1544 1544.5

Pow

er m

W

Phase noise at 10 kHz offset:

Open loop: -98 dBc/Hz

Close loop: -108 dBc/Hz

Electrical 10 Electrical 10 GHzGHz signal signal

0.47

Pow

er m

W

Wavelength nm

Optical SpectrumOptical Spectrum

Self-Starting Ultra Low Jitter Optical Self-Starting Ultra Low Jitter Optical Pulse SourcePulse Source

Harmonic spectral analysis (van der Linde technique):Harmonic spectral analysis (van der Linde technique):

0 1 2 3 4 5Harmonic number

Pow

er s

pect

rum 22

0222 nJAn

Amplitude noise contribution

Jitter contribution

high

low

f

f

xnx dfnffS )( 02,

-80

-60

-40

-20

0

10-50 GHz5 kHz/div

Pow

er d

Bm

1

5

Harmonic

number

Open loopOpen loop

Pow

er d

Bm

-80

-60

-40

-20

0

10-50 GHz5 kHz/div

Closed loopClosed loop

1

5

Harmonic

number


Jitter MeasurementsJitter Measurements

10 10 10 10 102 3 4 5 6

-120

-100

-80

-60

1

4

Harmonic

number

Closed Loop

0 1 2 3 4 50

0.05

0.1

0.15

0.2

0.25

0.3

0.35

Harmonic Number

RM

S N

oise

mW

100 Hz – 1 MHz

500 Hz – 1 MHz

500 Hz – 15 kHzCurve fit to 2

202 naan

Frequency range

Amplitude noise

RMS Jitter

500 Hz – 15 kHz 500 Hz –1 MHz 100 Hz –1 MHz

0.1 % 0.15 % 0.2 %

40 fS 43 fS 57 fS

Note that the 40 fs jitter (with a power of – 6 dBm and 10 km fiber) could not be improved with higher powers or longer fibers.

Pha

se N

oise

dBc

Hz

Offset Frequency Hz


Jitter MeasurementsJitter Measurements

ConclusionConclusion Photo HBT based oscillator – versatile multi functional Photo HBT based oscillator – versatile multi functional

systemsystem Accurate numerical modelAccurate numerical model Fundamental and Harmonic injection lockingFundamental and Harmonic injection locking Uni and bi-directional locking Uni and bi-directional locking Improved noise performance due to correlated noise Improved noise performance due to correlated noise

interaction in Harmonically locked oscillatorsinteraction in Harmonically locked oscillators Multi rate timing extractionMulti rate timing extraction Bi-directional locking – characteristics determinedBi-directional locking – characteristics determined

by mutual locking efficiency and relevant Q factorsby mutual locking efficiency and relevant Q factors Self starting low jitter mode locked diode laserSelf starting low jitter mode locked diode laser

The locking mechanismThe locking mechanism

Injected signal Injected signal xx1 1 ((tt)) saturates the gain saturates the gain

Loop lifetime is long Loop lifetime is long

Free running dynamics are overwritten by Free running dynamics are overwritten by

xx1 1 ((tt) for ) for

Fundamental LockingFundamental Locking

11stst QQ11 lock lock 33rdrd QQ11 lock lock 11stst QQ22 lock lock 33rdrd QQ2 2 locklock

102 103 104 105 106 107-120

-100

-80

-60

-40

-20

1:1

11stst QQ11 lock lock 33rdrd QQ11 lock lock 11stst QQ22 lock lock 33rdrd QQ2 2 locklock

1:2

102 103 104 105 106 107-120

-100

-80

-60

-40

-20

102 103 104 105 106 107-120

-100

-80

-60

-40

-20 11stst QQ11 lock lock 33rdrd QQ11 lock lock 11stst QQ22 lock lock 33rdrd QQ2 2 locklock

2:1

102 103 104 105 106 107-120

-100

-80

-60

-40

-20 11stst QQ11 free free 33rdrd QQ11 free free 11stst QQ22 free free 33rdrd QQ22 free free

free

102 103 104 105 106 107-120

-100

-80

-60

-40



5:1

102 103 104 105 106 107-120

-100

-80

-60

-40


7:1

102 103 104 105 106 107-120

-100

-80

-60

-40


10:1

102 103 104 105 106 107-120

-100

-80

-60

-40



1:5

11stst QQ11 lock lock 33rdrd QQ11 lock lock


1.5:1

102 103 104 105 106 107-120

-100

-80

-60

-40

-20

102 103 104 105 106 107-120

-100

-80

-60

-40



1:1.5

102 103 104 105 106 107-120

-100

-80

-60

-40


25:1

Feedback ModelFeedback Model

Phenomenological modelPhenomenological model Self starting from noiseSelf starting from noise Easy injection modelingEasy injection modeling Polynomial Non-Linear Gain Polynomial Non-Linear Gain

functionfunction BPF implemented as IIR filterBPF implemented as IIR filter

Delay Line

nsV Non-LinearGain

tx

injVsatV iV

rV

0

BPF

Q

Time domain simulationTime domain simulation Transmission line – like propagationTransmission line – like propagation Decimation in time incorporating long FIR filterDecimation in time incorporating long FIR filter Ensemble averaged PSDEnsemble averaged PSD

Numerical Results – Single OscillatorNumerical Results – Single Oscillator

Noise parameter Noise parameter cc derived for derived for Resulting PSDs agree perfectlyResulting PSDs agree perfectly PSD has a single pole functional formPSD has a single pole functional form

Indicates Gaussian statisticsIndicates Gaussian statistics CAN NOT be predicted by small signal analysisCAN NOT be predicted by small signal analysis

10 2 103 10 4 10 5 106-100

-90

-80

-70

-60

-50

-40

-30

-2011stst harmonics harmonics

22ndnd harmonics harmonics33rdrd harmonics harmonics44thth harmonics harmonics

Linear fitLinear fit

0 20 40 60 800

1

2

3

4

5

6

7

8SimulatedSimulated

Offset Frequency HzP

hase

Noi

sedB

cH

zTime μS

Per

iod

Tim

e V

aria

nce

s2

AnalyticalAnalytical

SimulatedSimulated

Injection Locked Oscillators Optoelectronic Applications E. Shumakher, J. Lasri, B. Sheinman, G....

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Transcript of Injection Locked Oscillators Optoelectronic Applications E. Shumakher, J. Lasri, B. Sheinman, G....