Transcript silicon photonics - 123seminarsonly.com

ARAVIND SURESH(Roll no:09)
S7A EC
SILICON PHOTONICS








2
OVERVIEW
Introduction
Optoelectronics at present
WDM
 AWG and WDM
Siliconize photonic
 Stimulated Raman Amplification
 The Raman effect Laser
 Silicon laser
 Modulator
 Coding of optical data
 Photodetector
 Interface
The silicon challenges
Applications
Futurescope & Conclusion
Reference
COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS
3
INTRODUCTION
•
•
•
•
•
•
•
•
•
Moore’s Law(1962)
Presently 1.7billion transistors
More transistors more information can process
Copper wires are used to communicate between peripheral
devices
Wires close to each other can induce currents in one
another
Increased resistance=increased heat =decay of data
Microscopic imperfection, Skin effect, Proxmity effect
Data speed > 10Gbps not achieved
Replace copper with optical fiber and electron with photon
COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS
4
OPTOELECTRONICS AT PRESENT
•
A single fiber strand can now carry up to 14Tbps
• Send pulses of light instead of pulses of electron current in guided
medium
•
Fibre Optics immune to attenuationrepeaters at over 100 Kms
•
Pack dozens of channels by separating channel by wave lengthWDM
“Wave length division multiplexing”
• Use lasers to shoot light pulses through glass fibers
• Need of coherent light
COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS
5
WDM
The wavelength division multiplexing
•
•
•
•
•
•
Multiplexing upto 160 channels
Bandwidth in the range : 1260-1675 nm
Single Mode Fibre core diameter only- 9 micrometer
Channel separation as low as 0.8 nm
Most commonly used is: C-band transmission window
: 1530-1565 nm
Uses AWG (de)multiplexer
COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS
6
AWG and WDM
•
Array of waveguides with constant length increment
• Diffraction and Interference play the role
• Advantages-low loss,low cost,ease of network
upgrading
• Precision Temperature control: +/-2 Degree C
COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS
7
SILICONIZE PHOTONICS
•
•
Means all components are integrated on the silicon chip
To siliconize photonic –
• A integrated light source
• Device that split, route and direct light on silicon chip
• Modulator to encode data into optical signal
• Photo detector to convert the optical signal back to
electrical bits
• Low cost high volume assembly methods
• Supporting electronic for intelligence and photonic
control
COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS
8
MILESTONES
•
•
•
•
•
•
•
All-Silicon LaserSilicon is an indirect bandgap material
Need an external source for initial light
Problem of misalignment of external laser
Raman effect 10,000 times stronger in silicon.
STIMULATED RAMAN SCATTERING (SRS) AMPLIFICATION
Intel disclosed development of first continuous wave all-silicon
laser(2005)
To be continued…
COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS
9
SRS
Stimulated Raman Scattering
•
•
•
•
•
•
•
Pump Laser-500 mW,980nm
Weak Data beam-1550nm(C-band)
Data beam energy passed to molecular vibration
Pump photon absorption
High energy photon emission and wavelength shift
Scattering reduced in C-band
Advantage
COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS
10
The Raman effect LASER
COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS
11
Silicon laser
•
Need wave guide for light beam
•
Two photons absorption
•
Silicon to absorb pump beam’s photon and release free electrons
•
Electron cloud reduce amplification
•
P-I-N diode in silicon laser
•
Dielectric mirrors in silicon laser
COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS
12
Silicon laser
COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS
13
Modulator





Modulation –switching one state to another state(on and off)
Two types of modulation
Direct modulation
-direct switching of source(on-off)-limit 10Gbps~12km
External modulation
-used for 10Gbps~100km+
Each time laser turn on it ’chirps’-un desired shift in
wavelength-data distortion
Use external modulator chirp free
-use lithium nobate-strong electro optic effect
External Phase modulation of light without disturbing source
COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS
14
Modulation
COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS
15
Encoding optical data(ASK-digital modulation)
The Mach–Zehnder interferometer
•
•
•
•
•
•
Split the laser into two
Apply electric field to one beam
Speed changes and out of phase
When recombine- result cancel out
No electric field apply -No speed variation and
same phase
When recombine beam encoded with 1’s and 0’s
COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS
16
COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS
MILESTONES
continued…
•
Silicon Modulator in GHz range
•
Early injection current modulator- diode switching
•
Free carrier plasma dispertion effect.
•
Difficulty to extract carriers out of the path..
•
20MHz limit for silicon modulator-a limit for silicon photonics
•
Intel demonstrated the first GHz silicon modulator(2005)
•
Speed upto 10 Gbps demonstrated with transistor like device to inject as well as
pull out carriers
•
Speed upto 18Gbps demonstrated with optical ring modulator
•
Disclosed the development of 40Gbps silicon modulator
COLLEGE OF ENGINEERING CHENGANNUR
17
SILICON PHOTONICS
18
Photo detector/Demodulation
•
Collect the photons and convert into electrical signal
• Semiconductor diode detectors-the frontrunners
-The PIN diode detector
-The Avalanche Photodiode detector
• InGaAs-least bandgap
• Avalanche detectors with built in amplification due to intense
electric field
• Noise, dark current and photocurrent fluctuations
• Response time-0.5ns typical
COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS
19
Demodulation & Detection
COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS
20
INTERFACE
•
The construct-Silicon on insulator
•
Connecting an optic fibre
•
Silicon chip-optic fibre interconnection
COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS
21
SILICON CHALLENGES

Kerr Nonlinearity effect
Refractive index varies proportional to square of electric field
intensity

Four wave mixing
Three waves scatter at a point to produce fourth wavelength
COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS
22
COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS
23
APPLICATIONS
•
Integrating into a Tera-scale system
•
Shrinking electronic/medical equipments
•
3D ICs
An artistic view
COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS
24
FUTURESCOPE & CONCLUSION
•
Intel moving on steps towards 50Gbps optical link
•
Optical Revolution in:ELECTRONICS AND COMMUNICATION ENGINEEERING
COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS
25
REFERENCES

www.ieeexplore.ieee.orgLipson, M.; Optical Fiber communication/National Fiber Optic Engineers
Conference, 2008.;Publication Year: 2008 , Page(s): 1 - 3





techresearch.intel.com
domino.research.ibm.com
en.wikipedia.org
Ebook on Silicon Photonics – Mario Paniccia (Intel Director, Photonics Lab)
Fibre Optic Communication – Harold Kolimbiris,Scenior
COLLEGE OF ENGINEERING CHENGANNUR