Optical MEMS

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Optical MEMS
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Micro-Optics

• Couplers, demultiplexers, switches, routers,
  etc.
• Display technology
• Mostly elements, not complete systems
• Thin-films
• MEMS devices
• Gratings
• Lasers

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Types of Optical MEMS

• Sources
• Waveguide Optics
• Free-Space Optics - ???????(FSO),???????????(FSP
  ),??? ???????????????????????????????
• Transmissive Optics
• Reflective Optics
• Diffractive Optics
• Detectors (CCD)

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Sources

• Thermal Emitters(???,??)
• Semiconductor Devices
• LEDs
• Laser Diodes
• Edge-Emitting(????????)
• VCSELs(Vertical Cavity Surface Emitting Laser
  ??????????)
• Note that these devices using microfabrication
  techniques, but are not considered MEMS
• Easily integrated
• Polymer Emitters

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Semiconductor Lasers

• Pumping usually with DC current (low power)
• Many wavelengths available
• Raw beams are elliptical/wedge shaped,
  astigmatic
• Compact, low input power
• Optical Power
• 0.1-5 mW typical
• HP (to 100 W) available in arrays
• Cost
• 15 - 10,000 (goes with power)

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A structure of Micro-Lasers
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Waveguides

• Waveguides electromagnetic radiation guided
  via total internal reflection
• Ultrafast Laser-written Guides
• Planar Waveguides
• Mixers and Switches
• Fiber Alignment
• ????????(????????? ????)???????

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Free-Space Optics

• Free Space Optics, or FSO,  offers
  high-performance and cost-effective alternatives
  to existing radio, microwave, leased-line and
  fibre-optic options.

Broadband Wireless Infrared Laser
Communications Between buildings
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Reflective Optics

• Applies reflective coatings to optical components
  requiring a low-signal-loss reflective finish.

Optical switch
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The explosive diagram of A single mirror of DLP
ship
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Diffractive Optics

• Diffraction is a particular type of wave
  interference, caused by the partial obstruction
  or lateral restriction of a wave.

Double-slit diffraction
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Bragg diffraction

• The Bragg formulation of X-ray diffraction (also
  referred to as Bragg diffraction) was first
  proposed by William Lawrence Bragg and William
  Henr Bragg in 1913 in response to their discovery
  that crystalline solids produced surprising
  patterns of reflected X-rays

By the definition of constructive interference ,
the separately reflected waves will remain in
phase if the difference in the path length of
each wave is equal to an integer multiple of the
wavelength. the path difference is given by d
sinq
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Detectors (CCD)

• A charge-coupled device (CCD) is an image sensor,
  consisting of an integrate circuit containing an
  array of linked, or coupled, capacitors sensitive
  to the light.

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A CCD chip in a camera