PHOTONICS @ IIT-MADRAS

Current status + Future opportunities

Prof. Anil Prabhakar

Dept. of Electrical Engineering, IIT-Madras

Photonics in EE

Component Technologies

SubsystemsInstruments

SystemsNetworks

Ananth, AnilBalaji, BijoyShanti

Anil, BalajiDeepa, Shanti

Hari, Mani

Activities span across basic laboratory research to commercialization

LaboratoriesExperimental OpticsFibre Laser LabGrating FabricationIntegrated OpticsOptical Networks

Funding• Seed – Gururaj Deshpande

• 2.5 Gbps test bed, new lab, new group

• Multiplier Grants• Telecom Centre of Excellence – Fibre Bragg Grating Facility• IRDE, Dehradun – Fibre Laser Laboratory• IRDE, Dehradun – Silicon Photonics• DST – Nanophotonics Centre• DIT – Fibre optic sensors• DBT – Bio-photonics, Metrology

• Opportunities• Telecom: 100 Gbps test bed, QKD, photonic integrated circuits• Fibre Lasers for material processing• Bioengineering and biomedical applications

Collaborations• Indo-Australian, Indo-Swiss, Indo-German

• Optical MEMS, nano-photonics

• Indo-EU (Dublin, Southampton)• All optical signal processing

• NCBS, Bangalore• Biophotonics

• INO• Passive optical network for the India-based Neutrino Observatory

• LIGO – India (MIT, Caltech, others)• International collaboration to observe gravity waves

Silicon photonicsDesign Simulation & Analysis Fabrication

Characterization Packaged devices to market

1X8 powersplitter

DWDM channel interleaver

Bijoy K. Das / Integrated Optics Lab

Directional Coupler on SOI

• Two S-bend waveguides

Cross Port

Bar Port

Input port

Asymmetric ridge waveguides

Bijoy K. Das / Integrated Optics Lab

Towards an integrated SoI platformRing Resonator Distributed Bragg Reflector

MZI

pin basedMZI

Bijoy K. Das / Integrated Optics Lab

Tunable MEMS diffraction grating

• Goal• To fabricate a diffraction grating whose period can be tuned

during operation.

• Technique• Surface micromachining• Electrostatic actuation

Grating structure (a) unactuated state (b) actuated state 1 (c) actuated state 2

Fabricated tunable grating structure with 24 microns period

Shanti Bhattacharya / MOEMS

All optical wavelength conversionFour wave mixing between the CW pump and the pulsed probe result in the transfer of data from probe to the conjugate.

Conjugate

Probe

Data

10 GbpsDeepa V. / Optical Comm

Fiber Bragg Gratings

• Resonant structures that have wavelength selective reflection

• Make very good sensors

• Fabricated using a phase mask and an excimer laser at 248 nm

0 2 4 6 8 10

6

20

34

48

62

76Temperature Map

Distance(Km)

Tem

pera

ture

[o C

]

Exp. 63 5 63 Deg.

Est. 63 5 63 Deg.

Balajis Srinivasan / Fibre Bragg Grating Faciltiy

High power pulsed fiber lasers• Compact, rugged multi-KW level pulsed fiber lasers• Seed followed by single or dual stage amplifiers• Double clad or Large Mode Area (LMA) fibres

Balajis S./ Fibre Laser Laboratory

Active Mode Locked Fibre Lasers

Regenerative mode lockingPulse width of 68ps

Optical cavity

Balajis S./ Fibre Laser Laboratory

STED Microscopy

Pulsed STED causes less thermal damage to the sample

Must get 2 pulsed high intensity lasers to synchronize

Anil Prabhakar / Imaging and Flow Facility, NCBS

Dark field plasmon coupled fluorescence

Incident laser beam at 532nm

Glass

Gold

PMMA + R6G

Objective

Anath K./ Experimental Optics Lab

Label free plasmonic sensor – Reflective configuration

0 10 20 30 40 50 60 70 80 900.4

0.5

0.6

0.7

0.8

0.9

1

Incident angle

Re

flect

ivity

Reflectivity v/s Incident angle with variation in analyte index

1.321.331.341.351.361.37

Anath K./ Experimental Optics Lab

Optical Coherence Tomography• Experimental Technique (Fourier Domain)

• Low coherence Interferometry

Cucumber slice (1.5 mm x 8 mm)

Human wrist pulse

Scotch tape

Need it for retinal imagingHealthcare Technology Innovation Centre

Shanti Bhattacharya / Experimental Optics Lab

17

Microfluidic flow analyzer – HIV detection

Control Flow rate

F2 FluorescenceSi-APD400V bias

1550 nm CW modulated fiber laser + 3dB

635 nm pulsed laser

S

B1 B2

F1

F3a

FBG@635nm

FR1

FR2

Side Scatter @ 1550nm, InGaAs gated APD, 60V bias

1550 nm pulsed laser

F3b

5 deg offset

Anil Prabhakar / Imaging and Flow Facility, CCAMP

Competitive AnalysisMethod of HIV

detectionMiniature flow

analyzerBC CyAn

ADPGuava

Easy-CyteBD

FACSCalibur

Price (INR) 1-2 lakhs 30-50 lakhs 30-50 lakhs 30-50 lakhs

Quantity of sample required 100-500µl 1-5ml 1-5ml 1-5ml

Cost per sample (INR) 100 500 500 500

Maintenance cost

Low High High High

Expertise requirement Low High High High

Portability High Low Low Low

Detection method

Parameters

Expertiserequirement

1 lakh ~ 1,400 Euro

Mega Science Projects• Involving multiple universities• International collaborations• Taking on some grand challenges

• What is the role of Photonics?

India-based Neutrino Observatory

Madurai

IIT Madras

Iron Calorimeter (ICAL) Modules

Each module has 10,000 detectorsMagnetized iron plates (a very large electromagnet)

Large Passive Optical Network

1 Mbps from each detector. 5 Mbps worst case8 rows x 8 columns on each plane, in each module

Resistive Plate Chamber

64 c

hann

els

from

eac

h R

PC

for

x,y

loca

lizat

ion

Neutrinos ionize the inert gas, and generate an avalanche pulse picked up by 2” strips

PON hardware – corner of each RPC

• Tx at 1310nm, -10 dBm, 1-5 Mbps• Rx at -35dBm• We can also look at 1x64 splitter• Need monitoring, timing, (x,y) and trigger information

Gravitational-Wave Detectors

image credit: Luis Calcada

26

Advanced LIGO

x10 better amplitude sensitivity

⇒ x1000 rate=(reach)3

⇒ 1 day of Advanced LIGO

» 1 year of Initial LIGO !

Slides on LIGO are courtesy the LIGO Scientific CollaborationSource: R. Adhikari, Caltech

27

LIGO• Detection confidence

• Locate sources• Decompose the

polarization of gravitational waves

GEO VirgoTAMA/LCGT

A Global Network

1 2

θΔL =

c δt

INDIGO?

Geographical relocation: science gains

Source localization error

Original plan2 +1 LIGO USA+ Virgo

LIGO-India plan1+1 LIGO USA+ Virgo+ LIGO India

LIGO-Aus plan1+1 LIGO USA+ Virgo+ LIGO Aus

Advanced LIGO detectors

LASERAEI, Hannover

Germany

SuspensionGEO, UK

Courtesy: Stan Whitcomb 30

Advanced LIGO Laser

• Design: Albert Einstein Institute, Germany• Higher power (reduce photon shot noise)

– 10W 180W• 10x improvement in intensity and frequency stability

31Quadruple Suspensions

• Quadruple pendulum:

• ~107 attenuation @10 Hz

• Controls applied to upper layers; noise filtered from test masses

• Seismic isolation and suspension together:

• 10-19 m/rtHz at 10 Hz

Fused silica fiber Welded to ‘ears’, hydroxy-catalysis bonded to optic

Magnet Actuator

Electrostatic Actuator

Courtesy: Stan Whitcomb 32

Advanced LIGO Mirrors• Larger size

– 11 kg -> 40 kg• Smaller figure error

– 0.7 nm -> 0.35 nm• Lower absorption

– 2 ppm -> 0.5 ppm• Lower coating thermal noise

• All substrates delivered• Polishing underway• Reflective Coating process starting up

33

Caltech LIGO Laboratory MIT

LIGO Hanford Observatory LIGO Livingston Observatory

University of Adelaide ACIGA

Australian National University ACIGA

Balearic Islands University (Mallorca !)Caltech LIGO

Caltech Experimental Gravitation CEGG

Caltech Theory CART

University of Cardiff GEO

Carleton College

Cornell University

Embry-Riddle Aeronautical University

University of Florida-Gainesville

Glasgow University GEO

NASA-Goddard Spaceflight Center

Hobart – Williams University

India-IUCAA

IAP Nizhny Novgorod

Iowa State University

INDIGO, India

Loyola New Orleans

Louisiana State University

Louisiana Tech University

MIT LIGO

Max Planck (Hannover) GEO

Max Planck (Potsdam) GEO

University of Michigan

Moscow State University

NAOJ - TAMA

Northwestern University

University of Oregon

Pennsylvania State University

Southeastern Louisiana University

Southern University

Stanford University

Syracuse University

University of Texas-Brownsville

Washington State University-Pullman

University of Western Australia ACIGA

University of Wisconsin-Milwaukee

LIGO Scientific Collaboration~40 institutions, ~550 scientists

Unilumen Photonics Pvt Ltd• Incubated by IIT Madras• Registered in 2012

• High power fibre lasers• Optoelectronics design

• 8 faculty in EE, 40 post-grad students• Another 6 in Physics, Engineering Design, Applied

Mechanical

• Growing visibility in international community• Larger role in developing Photonics in India• Need to form collaborations and teams• New opportunities in biophotonics, silicon photonics,

telecommunications, defense

• Organizers for Photonics 2012, in December.

Photonics @ IIT Madras