Ultrafast nonlinear optical processing in photonics integrated circuits:

Benjamin Eggleton

p gSlow light enhanced

j ggARC Laureate Fellow

Director, CUDOS - Australian Centre of Excellence Centre for Ultrahigh bandwidth Devices for Optical SystemsCentre for Ultrahigh-bandwidth Devices for Optical Systems

Institute of Photonics and Optical Science (IPOS)S h l f Ph i U i it f S dSchool of Physics, University of Sydney

Eggleton group

Ultrafast coherent communications

Quantum integrated photonics

Nonlinear opticalPhononics (SBS)

communications

photonics

Nonlinear optics Nanophotonics

Eggleton’s research

Chip-based ultrafast nonlinear optics

• The photonic equivalent of an ultrafast integrated circuit:

– Femtosecond optical response– Millimetre scale optical circuits

To achieve these we need:• To achieve these, we need:

Ultrafast light-light interaction (10-12s)Optical

response

Ultrafast light light interaction (10 s)

Waveguides in novel nonlinear materialsg

Photonic crystals (slow light enhanced NL)

Ultra-fast Kerr nonlinearity• Nonlinear optics provides ultra-fast manipulation of light (e.g. switching,)

)3()2()1( EEEEEEP

n = n + n I (Intensity dependentf i i d )

...0 EEEEEEP

n22 n = n0 + n2I refractive index)

Self-phase modulation (SPM)C ( )

effA

Cross-phase modulation (XPM) Phase matched processes (Four-wave mixing)

Third harmonic generationgRaman Scattering

Brillouin Scatttering

Planar waveguides As2S3

• Deposition of As2S3 film – Thermal evaporation

• Photolithography & dry etching• Photolithography & dry etching– n2~110×silica – Effective Area: ~1-5 µm2

– γ=2000 –25 000 W-1km-1γ=2000 25,000 W km– Prop. loss ~0.05-0.2db/cm– Dispersion engineered

Serpentine waveguide = 22 cm (~3dB loss)

Slow-light enhancement of NL effects

– Longer interaction time with material

vg~vphase

v <<v

• Effective nonlinearity ~ (slow-down factor)2

S ti l l i

vg<<vphase

– Spatial pulse compression – Enhanced interaction (path length)– Ultra-compact operations and potentially energy efficient– Ultra-compact operations and potentially energy efficient

Planar photonic crystal waveguides

• Planar photonic crystal:Slab (220nm)+2D PhC (air hole lattice a~400nm)

• Sub-µm optical confinement Aω ~0.4 µm2 Light

(k ) Vlasov et al. Nature 2005

(k,)

Even mode

kvg

Coherent backscattering

Flat band = Slow light

k

k [2/a]0 0.5= Slow light

Krauss J. Phys. D 2007

Slow light versus resonatornonlinear enhancement

Slow light dispersion engineered waveguides

Resonators: bandwidths from kHz to at most a few GHz....

1µm Carmon et al. Nature Physics 2007

vg~c/4010%10nm (1.2 THz) band 26µm

cw demonstrationsNarrow linewidth

( )« Flat-band »

Slow light

1µm

Application to high bit rate all-optical signal processing

Galli et al. Opt Express 18, 26613 (2010)

Conversion efficiency ~2.10-8

(100W in cw)

High bandwidth of the slow light PhC wgd

50

60

0

10640Gb/s 33% RZ Corcoran et al. Opt Express 18, 7770 (2010)

40

(ng)

-10

Po

30

oup

Inde

x

-30

-20

ower (dB

m

10

20Gro

-40

)

640Gb/s 33% RZ

0

10

1545 1550 1555 1560 1565 1570-60

-50

3dB BW ~ 7.5nm

1545 1550 1555 1560 1565 1570Wavelength (nm)

<100 micron optical switch

• Enhanced third harmonic generation

Principle of OPM monitoring

Slow Si PhotodiodePhotodiode

40 Gbit/s to 640Gbit/s signal640Gbit/s signal

ħωT

ħωT

ħωħωħωT

ħωT

ħωħω

ConstantTotal Av powerIn-band

ASE noise

Total Av. power ~ 100mW (input)/ ~10mW (coupled)

Corcoran et al. Opt Express 18, 7770 (2010)

OSNR/dispersion Monitoring

160Gbit/s14%

160Gbit/s14% duty cyclecycle

640Gbit/s33%

THG induced green light:A clear function of the di i /OSNR i d ddispersion/OSNR induced distortion of the signal

Corcoran et al. Opt Express 18, 7770 (2010)

PSA in Silicon PhC Waveguides

Gai

n

propagating phase

ωs ωi ωp 0 ϕ πPSA gain

PhCPhC + TPA = PSA ?+ TPA = PSA ?Slow light enhances nonlinearity

10

/ )

TPA limits nonlinearityPhCPhC + TPA = PSA ? + TPA = PSA ?

5

hase

shi

ft (

/TPA

No TPA

Krauss J. Phys. D 40 2666 (2007) 0 5 100Power (W)

ph TPA

PSA setup

TE

30 nm

SPSEDFAPC

SPS OSALaser

40 MHzPump: 15ps, 1W(peak)Signal/idler:8ps 10/20mW(peak)Signal/idler:8ps, 10/20mW(peak)

PSA in Silicon PhC Waveguides(postdeadline OECC 2013)

0

2

4

-40

-30

)

0.7

-40

-30

)

0.70.5-40

-30

)

0.70.50.2

-40

-30

)

0.70.50.2 +Gain

-4

-2

0

Gai

n (d

B)

-60

-50

nten

sity

(dB

)

-60

-50

nten

sity

(dB

)

-60

-50

nten

sity

(dB

)

-60

-50

nten

sity

(dB

)

10 dB

0 0 2 0 4 0 6 0 8 1-10

-8

-6

1552 1554 1556 1558 1560-80

-70

In

1552 1554 1556 1558 1560-80

-70

In

1552 1554 1556 1558 1560-80

-70

In

1552 1554 1556 1558 1560-80

-70

In

-Gain0 0.2 0.4 0.6 0.8 1

/1552 1554 1556 1558 1560

(nm)1552 1554 1556 1558 1560

(nm)1552 1554 1556 1558 1560

(nm)1552 1554 1556 1558 1560

(nm)

0

2

4

Max gainGain:

-6

-4

-2

Gai

n (d

B)

Mi i

11 dB

0 0.5 1 1.5-10

-8

Peak Power (W)

Min gain

Solitons compression in Bragg gratings and photonic crystals

Soliton compression in silicon photonic crystals

Key Points:-- Solitons possible in Si

(i) (strong FC disturb ideal Kerr-GVD dynamics)(ii) Spectral blue shift due to free-carriers [1 2]

N > 1 (compression regime)N2 = Ld / LNL

Ld=T02 / |2|

LNL=1 / (eff P0)

-- Frequency-resolved gating--Increasing power

(ii) Spectral blue shift due to free carriers [1,2](iii) Time domain acceleration [1]

-- Picojoule pulse energiesChallenging to measure these small pulse energie(< pJ collected off chip)

NL (eff 0)

EXPERIMENT (Time domain)Power coupled to PhC (< pJ collected off-chip)

--NLSE modelling underway

Power coupled to PhCEo ~ 10 pJ, c ~ 2

1.7 ps

Silicon

Dr Chad Husko

Silicon

See also:

Dr. Chad Husko(DECRA fellow)

Andrea Blanco(Marie CurieVisiting Ph.D.)

Dan Eades(Undergrad)

[1] Husko et al., Scientific Reports 3, 1100 (2013) – GaInP PhCsolitons

[2] Husko et al, CLEO US - QF1D.5 (Friday 9:15 AM)[3] Ding et al (Bath), Opt. Exp. 18, 26625 (2010) – Si wire WG

3.65 ps

Quantum integrated photonics

Tb/s coherent communications

Create world’s first photonic platforms for practical, scalable quantum information operations for secure communications based 

Free space optics

Q t

Mid IR integrated 

communications

Q t i t t d

pon single photons

Quantum integrated photonics

photonicsQuantum integrated photonics

Zeilinger et al, Quantum teleportation experiment

Photon pair generation by nonlinear mixing

Hybrid integration

Nanophotonics

Integrated platform

Heralded single photon sources

(3): Spontaneous four-wave mixing (SFWM)

H ld(3) medium

Herald2 Pump photons

DetectorsDetectors

Silica PCF Rarity, Opt. Express (2005).Silicon Waveguide Sharping, Opt. Express (2006).

Single PhotonSFWM!Input

Outputg p g, p p ( )

Silicon Rings Clemmen, Opt. Express (2009).Silicon Nanowire Harada, IEEE JSTQE (2010)Chalcogenide Waveguide Xiong, Opt. Letters (2010)Silicon Photonic Crystal Xiong, Optics Letters (2011).

pi sp pi sy g, p ( )

Silicon CROW Davanço, APL (2012).

Postdeadline CLEO 2011, BaltimorePostdeadline ECOC 2012 Amstedam

~centimeters

InputIdler and signal = pairs of correlated photons

Output

Spatially compressed pump pulse

centimeters

p

Output

p

pi s

Slow light Enhancement of the nonlinear FWM efficiencySlow light

“Fast” light

Slow light Enhancement of the nonlinear FWM efficiency

Ultra-compact sources (~100m)

Eggleton’s research

Fully integrated multiplexed single photon source

RF CMOS electronic logicSPDs C. Schuck, et. al., APL 102, p. 051101, 2013.

Pulsed pump laserlaser input

Heralded single gphoton outputNoise

porthttp://www.singlequantuN Silicon PhCW’s

Integrated AWG’s

FiberDelay

Low loss PLZTNx2 switch

portD. Dai et. al.,OpEx, 9, no. 15, p. 14130, 2011.

m.com/

• Multiplexing allows us to take probabilistic photon-pair sources and make asources and make a deterministic single photon source.

Further IntegrationC lli l N C i i i

196µm

63.1% enhancementCollins et al. Nature Communications, in-press.

196µm

g(2)(0) = 0.17

vg

λ

Eggleton’s research

Highly nonlinear chalcogenide glass

Our work: As2S3, As2Se3, Ge11As22Se67

High nonlinearity (ultra-fast ~ 50 fs response) n2 ~ 100-1000 x silica

Ultrafast pure Kerr effect (no free-carriers)

Low two-photon absorption Low two-photon absorption

Compatible with Photonic integration

Ultra-strong Raman/Brillouin scattering Ultra strong Raman/Brillouin scattering

Mid-infrared transparent (2-10m)

(TPA free)

(Postdeadline paper, ECOC September 2012)

29

Heralded single-photon generation

Coincidence to accidental ratio (CAR)

CAR > 350

Si PhCW

L 196CAR > 350 L = 196 µmϒ ~ 4000 W-1m-1

1. A. Clark et al, New J. Phys. 97, 211109 (2011)2. C. Xiong et al, Appl. Phys. Lett. 98, 051101 (2011)3. C. Xiong et al, Opt. Lett. 36, 3413 (2011)

Solution: Spatial multiplexing

B l b lti l i

Spontaneous nonlinear process: • nondeterministicUltra-compact on-chip single-photon sourcesBalance by multiplexing• high photon number state

Ultra compact on chip single photon sources

Nonlinear Fast feed-forward On demand l Nonlinear

Sources optical switch

Single mode

pump pulses(all from 1 laser) Detectors

Single modeOn demand Single photons!

Sources that randomly

Migdall Phys. Rev .A 66, 053805 (2002)

Sources that randomly generate photons

053805 (2002)PROPOSAL

Single photons enable…

Quantum computationQuantum communication

Si l h t Q t k• Single photon Quantum key distribution• Quantum teleportation

Integrated Optics!p

Free space optics

X. Jin, J. Ren, et al., NaturePhotonics 4, 376-381 (2010)

University of BristolPoliti, et al., Science 320, 646 (2008)