CUTTING-EDGE SILICON TECHNOLOGY FOR ENERGY-EFFICIENT … · Advent of Silicon Nitride photonics:...

LID 2019 – Photonics Workshop | Corrado SCIANCALEPORE | June 25, 2019

CUTTING-EDGE SILICON TECHNOLOGY FOR ENERGY-EFFICIENT NL QUANTUM PHOTONICS

| 2LID 2019 – Photonics Workshop | Corrado SCIANCALEPORE | 25/06/2019

1. Techno-economic challenges of an ICT-driven society

2. Evolution of integrated nonlinear optics (1961 =>)

3. Advent of Silicon Nitride photonics: breaking down the loss barrier

4. Miniaturized optical frequency comb sources

5. Quantum Si PICs for nonclassical states of light

6. Conclusions

SILICON TECHNOLOGY FOR NONLINEAR & QUANTUM PHOTONICS


CHALLENGES OF AN ICT-DRIVEN SOCIETY

Capacity/Energy Scalability/Functionality Security

*Nature Photonics (Huawei), 2018

56 Gbps Si-PIC (STm, 2016)

400 Gbps VCSEL module (II-VI, 2019)

Nanolasers on Silicon (UCB, 2012) QuESS Mission, China, 2018

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Scenarios for Si-PICs long-term evolution

Commercial products (100G/400G) available today

• Footprint/ConsumptionThermal managementUse of III-V materials

Add more lasers

NL OpticsMore-Moore

Nanophotonics

Reduce footprint/consumption dramaticallyStill not mature enoughIntrinsically space-limitedUse of III-V materialsThermal management

Creating light with light (All-optical KET)

Thermally-unlimited technology

Optical frequency combs

Multiple, stable entangled qubits

Compact, inexpensive, CMOS-friendly

LID 2019 – Photonics Workshop | Corrado SCIANCALEPORE | 25/06/2019

A MORE-(THAN)-MOORE SILICON PHOTONICS

*LETI, 2011-2019







6. Conclusions



NONLINEAR OPTICS EVOLUTION

First demonstration of SHG in a quartz crystal (1961)

Optical power used = 3 kW

Conventional wisdom about NL optics

2002 => onwards

1961

Missing something

What about integration ?

High-Q resonators Slow-Light







6. Conclusions


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ADVENT OF SILICON NITRIDE PHOTONICS: BREAKING DOWN THE LOSS BARRIER


Passivation for III-V lasers… …and transistor electronics

AC optical Kerr Effect

LETI

*V. Torres at al., OE, 2017

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FW

M

Linear optical medium

l

bp=2p/l neffp

lp

Signal and Idler generation

lpbi <bp< bs

ls li

2 hvp

Four-Wave Mixing (high intensity)

4-photon scattering matrix

2 hvp = hvs+hvi

ls li

EE l

*M Lipson et al., Columbia, Nature Phot., 2010

2009 New frequencies from a single laser line

Integrated microrings

CMOS-material (Si3N4)

Thermally unlimited OPG

Time-energy entangled photons source

Power-hungry (400 mW input power)

Need external fiber laser amplifier

Impossible to be cointegrated

Device failure

MI combs (RF noise) vs. Soliton-State

time-stable comb dynamics~ dB/cm waveguides

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High-confinement waveguides

SiO2 cladding

Si (SiN)

core

Si Substrate

n2=1.44

Sources of optical loss:

Sources of optical losses:

Scattering by sidewalls roughness Bulk absorption (mid-gaps, contaminants)

Substrate leakage

Nonlinear effects (TPA, FCA, FCD)

Surface-states absorption

0 0.5 1 1.5 2 2.50

0.5

1

1.5

2

2.5

3

3.5

Width (um)

(

dB

/cm

)

d (µm)

from F. P. Payne, J. P. R. Lacey, Optical and

Quantum Electronics 26, 977 (1994)

Loss by roughness scattering

With: j = Modal field amplitude at sidewalls x = Correlation length d = waveguide width b, q = modal propagation constant/vector

R = sidewalls roughness Dn = refractive index contrast

Losses by scattering soar for high-confinement/

High-g factor waveguides


2p n2gNL =

l0 Aeff


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Lipson et al., Nat Phot., 2010

T. J. Kippenberg et al., Optica 2016

2016

*LETI, 2017

2017

Catastrophic cracking

Uniaxial strain Twist-and-grow unlimited deposition

LiGENTEC, 2017Columbia, 2013

Damascene Process

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Pth = 86 mW

543 nm

490 nm 392 nm

780 nm

Credits: DTU Fotonik



THG SHG

SFG UV generation RMS ~ 1 nm

P1695 nm

2°

820 nm

2018

Optimized etching

(surface states and

roughness reduction,

passivation)

Chemical annealing

(bulk reorganisation,

index grading)

Record-low sidewall

roughness, void-free

encapsulation) *El Dirani et al, OSA/CLEO 2019, IEEE GFP 2019*Youssef et al., OSA FiO 2019, …

*El Dirani et al., Appl. Phys. Lett., 2018

*El Dirani et al., Submitted for publication, 2019







6. Conclusions



MINIATURIZED OPTICAL FREQUENCY COMB SOURCES

Losses/Q/gNL evolution (2016-2019)

xo

LIGENTEC 2018

v

Columbia 2018

High-Q Low-Q

Low- High-

Low

-gH

igh

-g

xxx

Towards chip-scale high-WPE NL optics

Record-low losses for high-gSi3N4 waveguides

< 1 dB/m

Required power for

comb generation

~100 µWLab test configuration

*Geiselmann et al., Optica, 2018

F > 7500

Qi > 2,5x107

LWH = 15 MHz



*CEA-LETI/III-V Lab, 2019 *Columbia, 2019

2019

Chip-based energy-efficient OFC sources

sech² fit

Soliton DKS state

Ultra-high QSi3N4 µring

Multimode-DFB laser / AR damage

No active tuning needed

Self-injection multi-lock

Free-running MM laser

Stable soliton operation

No need of low RIN/LNW lasers

Compact, low-power, damage-

resilient comb laser sources

Chip-size

*S. Boust et al., IEEE MWP 2019



, LETI/Thales, 2019Multi-DKS regime

Triple-DKS regime

Single-DKSFSR 200 GHz

FSR 600 GHz

FSR 1,2 THz

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6. Conclusions



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QUANTUM SI PICS FOR NONCLASSICAL STATES OF LIGHT

SiO2 cladding

Si core

n1=3.44

Si Substrate

n2=1.44

Si LER : 2,5 nm

Silicon after plasma etching

𝐻𝑜𝑤 𝑡𝑜 𝑖𝑚𝑝𝑟𝑜𝑣𝑒 𝑠𝑡𝑎𝑟𝑡𝑖𝑛𝑔 𝑓𝑟𝑜𝑚 𝑡ℎ𝑖𝑠 ?

2018

4,3

2,35

0,750

2

4

6

LE

R (

nm

)

After Si Etch After H2

plasma+ Si Etch

H2 Annealing

45%

83%

1E-3 0.01 0.1

1

10

100

1000 100 10

2-Si Etching

3-H2 plasma + Si Etching

4-H2 plasma + Si Etching+ H2@850°C

PS

D L

ER

left

(nm

3 )

Wavenumber k (nm-1)

Spatial Period l (nm)

Roughness frequency distribution


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Experimental results

H2–annealing atomic-scale smoothening

Scattering losses approaching sub-dB/cm

Enabling silicon optical performance

H2 annealing reduces surface roughness by 83%

LER = 0.75 nm RMS = 0.25 nm similar to Si bulk

1,2 dB/cm for 320 x 300 nm waveguides

LER = 0.75 nm

𝜉 = 250 nm

O-band


CEA-LETI / LTM

C-band

*C. Bellegarde et al., IEEE Phot. Technol. Lett., 2018*T. Horikawa et al., IEEE JSTQE, 2018




115-GHz silicon µrings with Qi > 600.000

Spontaneous FWM emission from the Si µ-ring

2018



Coincidences for Pin = 163 µW, Gr = 3,2 MHz

Second-order correlation function, Pin = 370 µW, 1h

Hanbury-Brown and Twiss experiment (HBT)

Generation of time-energy entangled photons pairs

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1. Techno-economic challenges of a ICT-driven society





6. Conclusions




CUTTING-EDGE SILICON TECHNOLOGY FOR ENERGY-EFFICIENT NLQ PHOTONICS

*Columbia, 2019 Applications overview

FMCW LiDAR using high-energy soliton pulsesSuper-K based time-of-flight sensors

50 Tb/s already demonstrated

Multi-Pb/s in sight

Time-bin entaglement

Time-energy entaglement

Ultra-bright quantum sources

BiOS & spectroscopyf-2f self-referencing

Optical clocks

50 Tb/s

CUTTING-EDGE SILICON TECHNOLOGY FOR ENERGY-EFFICIENT … · Advent of Silicon Nitride photonics:...

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