Siliconizing Photonics

1
Silicon Photonics
Dan Muffoletto, Adriane Wotawa-Bergen, Ed
Schmidt
2
Abstract

• Silicon photonics is the merging of silicon
  electronic components, and photonics.
• Silicon has revolutionized the electronics
  industry due to the following advantages
• Ready Availability
• High Purification Levels
• Easy Manufacture
• Thermal and Mechanical Properties
• Resulting in Low cost
• The electronics industry is finding limitations
  based on intrinsic properties in materials.
• Examples Speed limitations in interconnects
• Communications expectation to increase speed
  decrease size
• Photonics often provide an answer to these
  limitations although using past technology is not
  competitive fiscally. Creating photonics with
  silicon, promises the advent of a new low cost
  industry.

3
Can it Continue?
Demonstrating reality of Moores Law.
4
How Can Photonics Help?
The gate switch delay decreases as gate size
decreases, however once 200 nm is reached, the
wire delay significantly increases. The overall
time delay is the too large at small gate
lengths.
5
Architecture of Interconnects
Interconnects currently have 6 layers (left),
they are predicted to double in the next ten
years.
6
SIO Rib Wave-Guides
Silicon based nano-photonics are just recently
becoming realizable.
7
Fiber Optics
Wavelengths of materials must be within the Infra
Red wavelength to be used for communications.
This is due to characteristics of fibers.
8
Overview Necessary Functions
9
Silicon Lasing

• Uses Raman Effect, and PIN junction to remove
  electrons which disrupt the amplification

10
Raman Lasers
Raman lasers are lasers that use the Raman Gain
property to generate a laser beam, rather than
creating a laser beam in the conventional sense
where it is based on stimulated emission. Similar
to lasers, uses either fiber, crystal or gas as
an amplification medium. Use only a few hundred
miliwatts to several watts for pump
power Cutting edge Raman lasers use a P-I-N
style structure.
Cross Section of a PIN Junction
11
Raman Lasers

• How Raman Lasers Work
• Two lasers of marginally different wavelengths
  are propagated through a single medium
• Interference between the two beams causes the
  longer wavelength laser beam to be amplified
• This amplification is the result of crystal
  vibrations that cause scattering and interference

• Uses of Raman Lasers
• Cascades of Raman lasers can be used for doped
  fiber amplifiers
• A 589 nanometer Raman laser can be used as a
  laser guide star
• Possible applications in RGB color displays

12
Modulation
13
What is a Modulator?

• A device that encodes data onto a beam of light
• Aims for extremely high data rates
• Acts like a switch
• like a transistor for light

14

• Options
• Turn on and off the laser
• Heats laser more
• Chirping- Fluctuations in wavelength when turning
  on/off
• Mechanically have a shutter cover constant beam
• Too slow to encode data
• Split beam and shift light into/out of phase
• Silicon has a poor optio-electric effect (light
  speed wont change much in presence of electric
  field.

Modulation
15
How well can Silicon Modulate?

• Silicon has a poor electro-optic effect, which
  makes it difficult to use this effect for a
  modulator.
• What materials do?
• potassium di-deuterium phosphate (KDP)
• beta barium borate (BBO)
• lithium niobate (LiNbO3)
• lithium tantalate (LiTaO3)
• NH4H2PO4 (ADP).
• Other organic polymers too
• One possible solution is hybrid materials
• Expensive epitaxial growth

16
Intels Approach
17
Intels Recent Developments

• GHz Modulator
• Splits beam and controls phase shifts
• 50 times improvement over previous world record
  in silicon
• Other materials, such has lithium niobate, can
  achieve faster speeds
• Finally reaching the speed of current household
  technologies, and with silicon it can be done at
  a lower cost

18
Overcoming Silicon

• Uses the free carrier plasma dispersion effect,
  where charges in the waveguide change silicons
  index of refraction
• Previous techniques just injected the charge
  carriers, which slowly dissipate and thus limited
  speed.
• Intel used a transistor-like device to eject and
  remove the charge carriers to attain faster
  speeds.

19
Detection
20
Detection

• Silicon is transparent for IR light, so it can
  not detect it on its own
• Germanium is added to make the photo detector
  work in the range of 850nm to 1310 nm

21
Conclusions

The major elements to photonics Light Source
Guide Light Modulation Photo Detection Assembly L
ead to the development of Intelligence.
22
Sources

• http//www.intel.com/research/platform/sp/
• ftp//download.intel.com/technology/silicon/sp/dow
  nload/Intel_Advances_Silicon_Photonics.pdf
• http//www.spectrum.ieee.org/print/1915
• ftp//download.intel.com/technology/silicon/sp/dow
  nload/sipwp2.pdf
• http//domino.research.ibm.com/comm/research_proje
  cts.nsf/pages/photonics.projects.html
• http//ej.iop.org/links/rtr01ul,v/yjb33FX32xG7bIHP
  av5vpA/c326r1.pdf
• http//www.rpphotonics.com/silicon_photonics.html
• http//www.intel.com/technology/silicon/sp/glossar
  y.htm

23
Sources

• http//www.intel.com/research/platform/sp/
• ftp//download.intel.com/technology/silicon/sp/dow
  nload/Intel_Advances_Silicon_Photonics.pdf
• http//www.spectrum.ieee.org/print/1915
• ftp//download.intel.com/technology/silicon/sp/dow
  nload/sipwp2.pdf
• http//domino.research.ibm.com/comm/research_proje
  cts.nsf/pages/photonics.projects.html
• http//ej.iop.org/links/rtr01ul,v/yjb33FX32xG7bIHP
  av5vpA/c326r1.pdf
• http//www.rpphotonics.com/silicon_photonics.html
• http//www.intel.com/technology/silicon/sp/glossar
  y.htm