Downloaded 58 times
![Fiber Bragg Gratings
• Resonant structures that have wavelength selective reflection
• Make very good sensors 76
Temperature Map
Temperature [oC] 62
48
34
20
Exp. 63 5 63 Deg.
6 Est. 63 5 63 Deg.
0 2 4 6 8 10
Distance(Km)
• Fabricated using a phase mask and an excimer laser at 248 nm
Balajis Srinivasan / Fibre Bragg Grating Faciltiy](https://image.slidesharecdn.com/deshiitm-130309221935-phpapp02/85/Photonics-IITM-10-320.jpg)
Photonics @ IITM
- 1. PHOTONICS @ IIT-MADRAS Currentstatus + Future opportunities Prof. Anil Prabhakar Dept. of Electrical Engineering, IIT-Madras
- 2. Laboratories Photonics in EE Experimental Optics Fibre Laser Lab Grating Fabrication Integrated Optics Systems Optical Networks Hari, Mani Networks Anil, Balaji Subsystems Deepa, Shanti Instruments Ananth, Anil Component Technologies Balaji, Bijoy Shanti Activities span across basic laboratory research to commercialization
- 3. 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
- 4. 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
- 5. Silicon photonics Design Simulation & Analysis Fabrication Characterization Packaged devices to market DWDM channel interleaver 1X8 power splitter Bijoy K. Das / Integrated Optics Lab
- 6. Directional Coupler onSOI Asymmetric ridge waveguides Bar Port Input port Cross Port • Two S-bend waveguides Bijoy K. Das / Integrated Optics Lab
- 7. Towards an integratedSoI platform Ring Resonator Distributed Bragg Reflector MZI pin based MZI Bijoy K. Das / Integrated Optics Lab
- 8. Tunable MEMS diffractiongrating • Goal • To fabricate a diffraction grating whose period can be tuned during operation. • Technique • Surface micromachining • Electrostatic actuation Fabricated tunable grating structure with 24 microns period Grating structure (a) unactuated state (b) actuated state 1 (c) actuated state 2 Shanti Bhattacharya / MOEMS
- 9. All optical wavelengthconversion Four wave mixing between the CW pump and the pulsed probe result in the transfer of data from probe to the conjugate. Conjugate Probe Data Deepa V. / Optical Comm 10 Gbps
- 10. Fiber Bragg Gratings • Resonant structures that have wavelength selective reflection • Make very good sensors 76 Temperature Map Temperature [oC] 62 48 34 20 Exp. 63 5 63 Deg. 6 Est. 63 5 63 Deg. 0 2 4 6 8 10 Distance(Km) • Fabricated using a phase mask and an excimer laser at 248 nm Balajis Srinivasan / Fibre Bragg Grating Faciltiy
- 11. efficiency. Figure 2. Block diagram of the high-power amplifier in the MOPA Approach configuration. Our aim is to generate a high power pulsed laser by High power pulsed fiber lasers amplifying the output from a semiconductor laser diode using a Ytterbium (Yb)-doped double clad fiber. A double- clad fiber has an additional cladding with lower refractive index around the conventional cladding, thereby allowing Exper imental Results The above setup has been packaged in a rugged, portable box as shown in Fig. 3. Peak power of up to 500 W has been achieved for a 40 ns pulse at 25 kHz repetition rate at the the inner cladding to act as a waveguide for the pump output of 1st stage of MOPA, with a launched pump power • Compact, rugged multi-KW level pulsed fiber lasers radiation. The process of amplification in a double-clad fiber of 4.5 W. Preliminary characterization of output powers is represented in Fig. 1. The core of the fiber is doped obtained from the 2nd stage has indicated that output powers • Seed followed by single or dual stage amplifiers with ytterbium. The signal, which is to be amplified is in the order of a few kWs are possible with M 2 <1.5. Work coupled into the core of the fiber. The pump is absorbed is underway to scale the output power using multiple pump • Double clad or Large Mode Area (LMA) fibres in the overlap region of core and inner cladding. The pump absorption is almost uniform along the length. lasers for the second stage amplifier. Figure 1. Process of amplification in a double- clad fiber. The maximum output power which can be obtained from a single stage amplifier is limited by amplified spontaneous emission and nonlinear processes such as stimulated Ra- man scattering (SRS) and stimulated Brillouin scattering (SBS).In order to achieve the kilowatt power levels, a dual stage Master Oscillator Power Amplifier (MOPA) configu- ration is used which is shown in Fig. 2. The configuration consists of a stable master oscillator, which is capable of Figure 3. Experimental setup of dual stage MOPA. generating laser pulses of 40ns with repetition rate of 25 kHz. The first stage of the MOPA setup consists of a single mode double clad fiber. The limitations in power scaling Publication due to the above nonlinearities may be overcome by using Y. Panbiharwala, C. S. Kumar, D. Venkitesh, B. Srinivasan, Balajis S./ Fibre Laser Laboratory double clad fiber in the second a large mode area (LMA) "Investigation of self pulsing in Ytterbium doped high power stage. fiber amplifier," to be presented at Photonics 2012, Chennai.
- 12. Active Mode LockedFibre Lasers Regenerative mode locking Pulse width of 68ps Optical cavity Balajis S./ Fibre Laser Laboratory
- 13. 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
- 14. Dark field plasmoncoupled fluorescence Incident laser beam at 532nm PMMA + R6G Gold Glas s Objective Anath K./ Experimental Optics Lab
- 15. Label free plasmonicsensor – Reflective configuration Reflectivity v/s Incident angle with variation in analyte index 1 0.9 0.8 Reflectivity 0.7 1.32 1.33 1.34 1.35 0.6 1.36 1.37 0.5 0.4 0 10 20 30 40 50 60 70 80 90 Incident angle Anath K./ Experimental Optics Lab
- 16. Optical Coherence Tomography • Experimental Technique (Fourier Domain) • Low coherence Interferometry Scotch tape Cucumber slice (1.5 mm x 8 mm) Human wrist pulse Need it for retinal imaging Healthcare Technology Innovation Centre Shanti Bhattacharya / Experimental Optics Lab
- 17. 17 Microfluidic flow analyzer– HIV detection S B1 B2 1550 nm CW FR1 modulated fiber 5 deg offset Control Flow rate laser + 3dB FR2 FBG@635nm 635 nm pulsed F1 F2 Fluorescence laser Si-APD 400V bias F3a F3b Side Scatter @ 1550nm, 1550 nm pulsed InGaAs gated APD, 60V bias laser Anil Prabhakar / Imaging and Flow Facility, CCAMP
- 18. Competitive Analysis Detection Miniature flow Method of HIV BC CyAn Guava BD method detection Parameters analyzer ADP Easy-Cyte FACSCalibur Price (INR) 1-2 lakhs 30-50 lakhs 30-50 lakhs 30-50 lakhs Quantity of sample 100-500µl 1-5ml 1-5ml 1-5ml required Cost per sample 100 500 500 500 (INR) Maintenance Low High High High cost Expertise Low High High High requirement Portability High Low Low Low 1 lakh ~ 1,400 Euro
- 19. Mega Science Projects •Involving multiple universities • International collaborations • Taking on some grand challenges • What is the role of Photonics?
- 20. The nearest major India-basedNeutrino Observatory city: Madurai South I ndia, ne the ar te IIT Madras m city ple of Madurai Madurai 8
- 21. Iron Calorimeter (ICAL)Modules Each module has 10,000 detectors Magnetized iron plates (a very large electromagnet)
- 22. Large Passive OpticalNetwork 1 Mbps from each detector. 5 Mbps worst case 8 rows x 8 columns on each plane, in each module
- 23. Resistive Plate Chamber 64 channels from each RPC for x,y localization Neutrinos ionize the inert gas, and generate an avalanche pulse picked up by 2” strips
- 24. 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
- 25. Gravitational-Wave Detectors imagecredit: Luis Calcada
- 26. Advanced LIGO x10 betteramplitude sensitivity x1000 rate=(reach)3 1 day of Advanced LIGO » 1 year of Initial LIGO ! Slides on LIGO are courtesy the LIGO Scientific Collaboration Source: R. Adhikari, Caltech 26
- 27. A Global Network GEO Virgo LIGO TAMA/LCGT • Detection confidence • Locate sources • Decompose the polarization of gravitational waves INDIGO? 1 2 27
- 28. Geographical relocation: sciencegains Source localization error Original plan 2 +1 LIGO USA+ Virgo LIGO-India plan LIGO-Aus plan 1+1 LIGO USA+ Virgo+ LIGO India 1+1 LIGO USA+ Virgo+ LIGO Aus
- 29. Advanced LIGO detectors LASER AEI, Hannover Germany Suspension GEO, UK
- 30. Advanced LIGO Laser •Design: Albert Einstein Institute, Germany • Higher power (reduce photon shot noise) – 10W 180W • 10x improvement in intensity and frequency stability Courtesy: Stan Whitcomb 30
- 31. 31 Quadruple Suspensions • Quadruple pendulum: • ~107 attenuation @10 Hz Magnet Actuator • Controls applied to Electrostatic upper layers; noise Actuator filtered from test masses Fused silica fiber Welded to ‘ears’, hydroxy- catalysis bonded to optic • Seismic isolation and suspension together: • 10-19 m/rtHz at 10 Hz
- 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 Courtesy: Stan Whitcomb 32
- 33. 33 LIGO Scientific Collaboration ~40 institutions, ~550 scientists Caltech LIGO Laboratory MIT LIGO Hanford Observatory LIGO Livingston Observatory University of Adelaide ACIGA Loyola New Orleans Australian National University ACIGA Louisiana State University Balearic Islands University (Mallorca !) Louisiana Tech University Caltech LIGO MIT LIGO Caltech Experimental Gravitation CEGG Max Planck (Hannover) GEO Caltech Theory CART Max Planck (Potsdam) GEO University of Cardiff GEO University of Michigan Carleton College Moscow State University Cornell University NAOJ - TAMA Embry-Riddle Aeronautical University Northwestern University University of Florida-Gainesville University of Oregon Glasgow University GEO Pennsylvania State University NASA-Goddard Spaceflight Center Southeastern Louisiana University Hobart – Williams University Southern University India-IUCAA Stanford University IAP Nizhny Novgorod Syracuse University Iowa State University University of Texas-Brownsville INDIGO, India Washington State University-Pullman University of Western Australia ACIGA University of Wisconsin-Milwaukee
- 34. Unilumen Photonics PvtLtd • Incubated by IIT Madras • Registered in 2012 • High power fibre lasers • Optoelectronics design
- 35. Photonics @ IITMadras • 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.