open lab prof. sorger aj/bit modulators and photonic ...€¦ · open lab prof. sorger volker...

OPEN Lab Prof. Sorger

Volker Sorger

14th NSF-Korea Nanotechnology Forum 2017

aJ/bit Modulators and Photonic Neuromorphic Computing


Orthogonal Physics Enabled Nanophotonics (OPEN) lab

compared to any photonic (non-plasmonic) mode and cavity structures where any placement of the metallic contact

close to the optical mode will introduce intolerable losses. This is different for our plasmonic mode, which is

inherently lossy, but the polaritonic (matter-like) mode allows to scale-down the device into a few micrometer small

device (a reduction of a factor of 100) compared to traveling-wave Silicon-based modulators. This ‘in-the-device-

basing’, as suppose to biasing the device few to 10’s of micrometer away from the active region. As such, the overall

design allows for a more compact overall footprint. Lastly, reducing the dielectric thickness (tox = 5 nm), improves the

electrostatics enabling a sub-1 Volt modulation performance. Despite this increasing the capacitance, the lower Rc and

small device area (5 mm2) the energy consumption is relatively low 18 fJ/bit. However, this can be further improved by

only biasing the device in the steepest region of the transfer function (e.g. 0-0.3V) for a small-signal modulation, and

narrowing the waveguide width from (currently 1 mm) to a SOI diffraction-limited waveguide width of 250 nm

reducing the E/bit to low 160aJ (Fig. 1d).

In summary, we have experimentally shown a graphene-based silicon-photonics integrated electro-absorption

modulator operating at telecom frequencies. Utilizing a hybrid-photon-plasmon modes high group index, field-

concentration to increase the optical overlap factor with the thin graphene active material, and improving the

electrostatics by reducing the gate oxide allows for a steep switching transfer function to enable sub-1 Volt

modulation, which has positive impacts on energy-efficiency. Further improvements allow for a 160aJ/bit efficient

modulator using this approach platform, thus paving the way for next-generation nanophotonics devices [13]. !

References [1] R. A. Soref, D. L. McDaniel, B. R. Bennett, “Guided-Wave Intensity Modulators Using Amplitude and-Phase Perturbations”

IEEE Journal of Lightwave Technology, vol. 6, no. 3, (1988).

[2] K. Liu, S. Sun, A. Majumdar, V. J. Sorger, “Fundamental Scaling Laws in Nanophotonics” Sci. Rep., 6, 37419 (2016).

[3] S. K. Pickus, S. Khan, C. Ye, Z. Li, and V. J. Sorger, “Silicon Plasmon Modulators: Breaking Photonic Limits” IEEE Phot.

Soc., 27, 6 (2013).

[4] M. Liu, X. Yin, E. Ulin-Avila, B. Geng, T. Zentgraf, L. Ju, F. Wang, and X. Zhang, “A graphene-based broadband optical

modulator,” Nature, vol. 474, no. 7349, pp. 64–67, (2011).

[5] M. Liu, X. Yin and X. Zhang, "Double-Layer Graphene Optical Modulator", Nano Letters, 12, no. 3, pp. 1482-1485, (2012).

[6] C. Ye, S. Khan, Z. R. Li, E. Simsek, V. J. Sorger (2014). “λ-size ITO and graphene-based electro-optic modulators on

SOI”. Selected Topics in Quantum Electronics, IEEE Journal of, 20(4), 40-49 (2014).![7] C. Ye, K. Liu, R. Soref, V. J. Sorger, “3-Waveguide 2x2 Plasmonic Electro-optic Switch” Nanophot., 4, 1, pp. 261-268 (2015).

[8] Z. Ma, M. Tahersima, S. Khan, V. J. Sorger, IEEE J. Sel. Topics in Quantum Electronics, 23(1), 3400208 (2017).

[9] R.Amin, C.Suer, Z.Ma, J. B. Khurgin, R. Agarwal, V. J. Sorger, “Active Material, Optical Mode and Cavity Impact on electro-

optic Modulation Performance”, arXiv:1612.02494, (2017)

[10] V. J. Sorger, R. Ma, C. Huang, Z. Li, M. Liu, and X. Zhang, "Graphene, Plasmonic and Silicon Optical Modulators,"

Conference on Lasers and Electro-Optics - IQEC,OSA, (2013).

[11] Z. Ma, Z. Li, K. Liu, C. Ye, V. J. Sorger, “Indium-Tin-Oxide for High-performance Electro-optic Modulation”, Nanophot., 4, 1

(2015).

[12] Ansell, D. et al. Hybrid graphene plasmonic waveguide modulators. Nature Commun. 6, 8846 (2015). [13] A. Fratalocchi, C. M Dodson, R. Zia, P. Genevet, et al. “Nano-optics gets practical”, Nature Nanotech. 10, 11-15 (2015).

Figure 1. a, Schematic of a hybrid-photon-plasmon

graphene-based electro-absorption modulator. The

modulation mechanism is based on Pauli-blocking upon

gating the Fermi level of graphene. b, Silicon waveguide-

integrated modulator. A cw laser (l = 1.55 mm) is fiber

coupled into the SOI waveguide via grating couplers.

Device length, L = 8 mm, tox = 5 nm. c, Electric field

density across the active MOS region of the modulator

showing an enhanced field strength coinciding with the

active graphene layer. This improves the optical overlap

factor by about 25%. Taking into consideration the grain

boundaries introduced during the metal deposited creates

in-plane field vectors inside the graphene layer. d

Modulator transfer function; normalized modulation depth

at different drive voltages (VD). The modulator

performance yields a high extinction ratio of 0.25dB/mm,

due to the combination of the plasmonic MOS mode

enhancing the electroabsorption in the active region (see

text for details).

!

Modulator

(i) (ii)

(iii) (iv)bias

input

output

Electro-OpticNonlinearity

ElectronicNonlinearity

pump

output

input

bias

output

input

output

pump

input

inputs

(c)

T(λ) output

input

t t t

λ1 λ2 λ3 λ1 λ2 λ3 λ4

photo-detector

spectralfilter

I(t) I(t) i(t) I(t)

t

weights summation nonlinearity output

(a)

(b)

!x1

x2

x3

w1

w2

w3

x⌃

f (x⌃ )

X

i

wi x ix4

modulator/laser

Laserelectrical wire

lightwave

Atto-Joule Optoelectronics

Photonic Functions

Analogue Computing

Today

Sorger, Zhang lab, Nature Photonics (2008) Sorger, Zhang lab, Nature (2009) Sorger lab , IEEE Photonics (2013) Sorger lab, Altug lab, Nature Nanotech. (2015) Sorger lab, Majumdar Lab, Sci. Reports (2016) Sorger lab, Optics Letters (2016) Sorger lab, IEEE STQE (2014 & 2017)

Sorger lab, IEEE Photonics (2015) Sorger lab, Nanophotonics (2016) Sorger lab, Optics Letters (2016) Sorger lab, El-Ghazawi lab, IPCC (2017) Sorger lab, El-Ghazawi lab, Mircoprocess. & MS (2017) Sorger lab, Frontiers in Optics (2017)

Sorger lab, Nanophotonics (2017) Sorger Lab, Grace lab, Biofabrication (2017) Sorger lab, IEEE Rebooting Computing (2017) Prucnal lab, Sorger lab, (in preparation)

OPEN Lab Prof. Sorger OPEN Lab

Prof. Sorger

5cm x 1cm

Modulators = Optical Transistors

EO Modulator

(=SS@FET)


Power-BW Roadmap

V. J. Sorger, Nature Nanotech., 10, 11-15 (2015)

Power = E bit( ) × Bitrate( )

J

bit

bit

s=

J

s= W

é

ëê

ù

ûú


EO Modulators

Sorger, Nanoph. (2012) Huang, IEEE Phot. (2013)

Ye, IEEE STQE (2014) Khan, (under review)

Ma, IEEE STQE (2017)

LASER &PHOTONICSREVIEWS

Vol. 9 | March 2015

Review and perspective on ultra-fast wavelength-size electro-optic modulators

Ke Liu, Chenran Ye, Sikandar Khan, Volker J. Sorger

www.lpr-journal.org Vol. 9 | March 2015 www.lpr-journal.org

Selective switching of individual multipole resonances in single dielectric nanoparticles

Pawel Wozniak, Peter Banzer, Gerd Leuchs

LASER &PHOTONICSREVIEWS

LPOR_9_2_cover.indd 2 11/03/15 5:05 PM

Sarpkaya, (in prep)

Grating period: 1um Fill Factor: 50%

Slot Gap < 50nm achieved Single EBL Exposure

ER = 1.2dB/um (single layer graphene)

ON

OFF 20 mm

5 mm

Control

2H 2H

1T’ Tr

ansm

issi

on

Control-Voltage

15 15

E/bit (fJ)

3.4

0.3

15

2.4 (0.16)


E/bit Scaling: FET vs. EAM

300K = 0.004aJ

= 4aJ

= 4fJ

15fJ

3fJ

0.3J

Boltzmann Approximation (=Thermal Smearing)

Sorger Group EAMs (Time not to scale)

10’s aJ Cavity

Finesse = 10

Mode Material

HPP ITO

HPP Graphene Slot Gr or TMD

SIS TMD

Technology Gap With equal E/bit, Photonics performance over Electronics:

1) <10x speed (<100GHz EAM vs. <2GHz link) 2) <1-5x WDM (depending on link length)

Sorger Nanophot. (2012)

Khan, (in review)

Ma, IEEE STQE (2017)

Cavity design based on Liu, J. Nanoph.(2015)

•

Thermally Unattainable Without Cooling

Transistors by (Intel)

Sorger Group, J. Opt., special issue (submitted)

100x


HyPPI: Hybrid Plasmon Photonics Interconnect

Sun, Badaway, Narayana, El-Ghazawi, Sorger, IEEE Photonics, 7,6 (2015).

High BFD

Mid BFD

low BFD

Electrical

Plasmonic Photonic

HyPPI (this work)

* BFD: Bit Flow Density [Gbps/um2]

Physics & Material (E/bit)Device SNR @ Rx Desired BER


Photonic Reconfigurable Computing

2015 2016 2017

MorphoNoC

DEVICE

LINK

NETWORK

SYSTEM & APPLICATION

HyPPI BFD

MoDetector

Universal CLEAR

For P

eer Review

Fig. 2 Capability-to-Length-Energy-Area-Resistance (CLEAR) based performance-cost comparison

between electrical (red) and hybrid photon-plasmon (blue) on-chip interconnect links as a function of link

length and technology evolution time. The chip scale (CS = 1 cm) link length and current year (2016) are

denoted in red. The following models are deployed; a) A capacity-area model based on the number of

transistors and on-chip optical devices, which can be regarded as the original Moore’s Law model; b) An

energy efficiency model is derived based on Koomey’s law, which is bounded by the kBT ln(2) ≈ 2.75zJ/bit,

Landauer limit (kB is the Boltzmann constant; T is the temperature); c) A the economic resistance model

based on technology-experience models and at the year 2016, the electronic link cost less than one billionth

to one millionth of the cost of the hybrid link; and d) A model for parallelism (after year 2006) capturing

multi-core architecture and the limitation from ‘dark’ silicon concepts in electrical link interconnects. The

yellow data point represents the actual CMOS silicon photonic chip that IBM fabricated in 2015.

Page 5 of 5 Spectrum

Link-CLEAR

Dynamic-CHyPPI HyPPI NoC

D-CHyPPI based Camera Sensor

Noise HyPPI

5x5 Optical Router

Fundamental Scaling Law

G. Pomrenke F. Darema

El-Ghazawi & Sorger Groups


Optical on-chip FFT

Hillerkus OE (2011)

Cooley-Tukey Method Addition

Multiplication

Sorger Group, Frontiers in optics (2017)


Convolutional Neural Networks based-on Optical FTT

Sorger Group, IEEE Computing (2017)


Mirror Symmetry Density with Delay in Spiking Neural Networks

Sorger Group. (2017) submitted


Prof. Volker Sorger sorger.seas.gwu.edu [email protected]

OPEN Sorger Team

Post Docs Grad Students U-grads Collaborators

Dr. I. Sarpkaya Dr. Ke Liu Dr. Hasan Goktas Dr. Elnaz Akbari

Mohammad Tahersima Sikandar Khan Matt Zhizhen Shuai Sun Jonathan George Rubab Amin Hani Nejadriahi Seyed Haghshenas Rohit Hemnani

D. D’Hemmecout T. Weinshel J. Crandall

Prof. Majumdar (UW) Prof. Agarwal (UPenn) Prof. Kimerling (MIT) Prof. Reed (Stanford) Prof. Bartels (UCR) Prof. Lee (KU) Prof. Prucnal (Princeton ) Prof. El Ghazawi (GWU) Dr. Sadana (IBM Watson) Prof. Cesare (NTU)

open lab prof. sorger aj/bit modulators and photonic ...€¦ · open lab prof. sorger volker...

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