‫بسم هللا الرحمن الرحيم‬
Micro Opto-Electro-Mechanical Systems
(MOEMS)
Hamdy Fadl
500512011
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Outlines
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MOEMS overview
Applications
Packaging
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‫الحسن بن الهيثم‬
al-Ḥasan ibn al-Haytham
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al-Ḥasan ibn al-Haytham
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Manuscript ‫مخطوطة‬
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What is MOEMs ?
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Micro-opto-electromechanical systems (MOEMS), or
optical MEMS, are systems involving micromachining
of structures in the micro- to millimeter range whose
purposes are to manipulate light.
It is not a special class of Micro-Electro-Mechanical
Systems (MEMS) but in fact it is MEMS merged with
Micro-optics which involves sensing or manipulating
optical signals on a very small size scale using
integrated mechanical, optical, and electrical systems
.
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Today’s MOEMS devices include Optical
Switch , waveguides, moving mirrors
and diffractive gratings
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*Micromachining : techniques for fabrication of 3D
structures on the micrometer scale
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Applications include MEMS devices
Most methods use silicon as substrate
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MOEMS Fabrication
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MOEMS devices are typically made using
standard lithography methods giving the
advantages of a compact design and
fabrication at a low cost.
These devices are usually fabricated using
micro-optics and standard micromachining
technologies using materials like silicon,
silicon dioxide, silicon nitride and gallium
arsenide.
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MEMS+MO=MOEMS
how is that ?
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During early 1990s, Rockwell Science Center,
with government sponsors, contributed to the
development of micro-optics technology
Teamed with MIT/Lincoln-Lab.
1992, Rockwell applied micro-optics to the
system development of several industrial
applications, including:
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microlenses for silicon focal planes high speed
binary microlens in GaAs, antireflection surfaces
in silicon thin film microlens arrays, etc.
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Rockwell Science Center also developed refractive
microlens technology, including gray scale
photolithography.
Diffractive microlenses based on binary optic
structures are typically fabricated in bulk material by
multiple sequential layers of photoresist patterning
and reactive ion etching (RIE), to form a multi-step
phase profile.
This profile approximates the ideal kinoform lens
surface. A special staircase process, called binary
optics, is used to fabricate diffractive components.
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With so many successes in Micro-optics and
MEMS, Rockwell researchers who were
involved in both MEMS and Micro-optics,
initiate development of several of innovative
photonics ideas combing both technologies.
This was behind the acronym of MOEMS,
when both MEMS and Micro-optics were
merged in one single IC processing lab.
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MOEMS is a promising multi technology for
miniaturization of critical optical systems.
The acronym is defined of three high tech
fields of micro-optics, micromechanics, and
microelectronics.
MOEMS indirectly could merge in
micromachining, microsensors and
microactuators if their processes are
compatible with integrated circuits.
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Merging all these multi technologies,
made MOEMS an ideal knowhow for
many industrial demonstrations of
commercial devices, such as optical
switches, digital micromirror devices
(DMD), bistable mirrors, laser scanners,
optical shutters, and dynamic
micromirror displays.
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Hybridization
Figure 1 : Merging Technology
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MEOMS and commercial
applications
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Attractive for comercial application
because of :
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batch processing and embossed replication
enabling technology for applications that
cannot be addressed, using micro-optics
The trend toward miniaturization and
integration of conventional optical systems
desirable elements of optical
communication.
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What is the difference between
Optical MEMS and MOEMS?
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Optical MEMS could include bulk
optics but MOEMS is truly based on
microtechnology
where MOEMS devices are batched
processed exactly like integrated
circuits, but this is not true in most
cases for Optical MEMS.
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Time for Applications!
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Applications
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Optical switch
Wave guide
Moving mirror
Diffractive grating
Microlens arrays
Microbolometers
Bistable Fabry Perot resonator for high
accuracy measurement of gas concentration
Micro-optical microphone to measure air
pressure.
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Optical Switch
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Many optical components are required in the rapid
development of optical networks, including optical
switches.
Optical switches in micro-opto-electro-mechanical
systems (MOEMS) have many applications because of
their excellent features, including low insertion loss
and crosstalk.
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In telecommunications, insertion loss is the loss
of signal power resulting from the insertion of a device in
a transmission line or optical fiber and is usually expressed
in decibels (dB).
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Optical Switch
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Then , what is Optical switch?
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In telecommunication, an optical switch is
a switch that enables signals in optical
fibers or integrated optical circuits (IOCs) to be
selectively switched from one circuit to another.
Away from telecom, an optical switch is the unit
that actually switches light between fibers
Fast optical switches, may be used to perform
logic operations.
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Example : 3D-MEMS Optical
Switch
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In a MEMS optical switch, a micromirror is used to reflect a light beam.
The direction in which the light beam is
reflected can be changed by rotating
the mirror to different angles, allowing
the input light to be connected to any
output port.
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3D-MEMS Optical Switch
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3D-MEMS Optical Switch Features
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Can switch optical signals without
converting them into electrical signals.
Allows compact low-loss switches to be
formed on any scale.
Switching can be performed in 10-30
msec.
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3D-MEMS Optical Switch usages
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Since this device can switch large
numbers of optical signals
simultaneously,
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it can be used as a trunk switch for
handling large amounts of traffic,
and as a switch in large urban
communication networks.
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Another Application : Waveguide
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A waveguide is a structure that guides
waves, such as electromagnetic
waves or sound waves. There are
different types of waveguides for each
type of wave.
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Waveguide
Dispersion, whale, shark
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Some naturally occurring structures can
also act as waveguides. The SOFAR
channel layer in the ocean can guide the
sound of whale song across enormous
distances.
The SOFAR channel( short for Sound
Fixing and Ranging channel ,)or deep
sound channel(DSC is a horizontal
layer of water in the ocean at which
depth the speed of sound is at its
minimum. The SOFAR channel acts as
a waveguide for sound, and low
frequency sound waves within the
channel may travel thousands of miles
before dissipating .
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Waveguide in MOEMS
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Fiber-optic waveguides based (MOEMS)
form a significant class of biosensors
which have notable advantages like
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light weight,
low cost
and more importantly, the ability to be
integrated with bio-systems.
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Example :integrated microfluidic fiber-optic
waveguide biosensor .
The fiber-optic waveguide is integrated with
bulk micromachined fluidic channel across
which different chemical and biological
samples are passed through.
The significant refractive index* change due
to the presence of biological samples that
causes the evanescent field condition in the
waveguides leads to optical intensity
attenuation of the transmitted light.
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Representative image for
waveguide in biosensor
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Refractive index
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In optics the refractive index or index of
refraction n of a substance (optical medium) is a
dimensionless number that describes how light, or
any other radiation, propagates through that
medium. It is defined as
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n= c/v
where c is the speed of light in vacuum and v is the
speed of light in the substance.
For example, the refractive index of water is 1.33,
meaning that light travels 1.33 times as fast in
vacuum as it does in water
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The speed of light
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The speed of light in vacuum,
commonly denoted c, is a universal
physical constant.
Its value is 299,792,458 meters per
second
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Speed of light
Sunlight takes about 8 minutes 19 seconds to reach
the Earth (based on the average distance).
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Evanescent waves
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An evanescent waves are formed at the
boundary between two media with different
wave motion properties, and are most intense
within one third of a wavelength from the
surface of formation
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evanescent waves
The exponential dependence of the
electromagnetic field intensity on the
distance away from the interface
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Micro lenses
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Microlens is a small lens, generally with
a diameter less than a millimetre (mm)
and often as small as 10 micrometres
(µm).
The small sizes of the lenses means
that a simple design can give good
optical quality
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Micro lens and Microlens Array
Single microlenses are used to couple light to
optical fibres
 while microlens arrays are often used to
increase the light collection efficiency of CCD
arrays. They collect and focus light that
would have otherwise fallen on to the nonsensitive areas of the CCD*.
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*A charge-coupled device (CCD) is a device for the
movement of electrical charge, usually from within the
device to an area where the charge can be manipulated,
for example conversion into a digital value.
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Microlens in Digital Camera
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Applications of Microlenses
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Microlens arrays are in digital projectors, to
focus light to the active areas of the LCD
used to generate the image to be projected.
Current research :microlenses act as
concentrators for high efficiency photovoltaics
for electricity production.
Form compact imaging devices for
applications such as photocopiers and mobilephone cameras.
3D imaging and displays
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3D imaging Display
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3D imaging Microscope using
Microlenses Array
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MOEMS packaging
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Encapsulation of electronics and sensors has
traditionally been used as a protection
against the outside environment, but through
integration of other functions (e.g. lenses,
electric and optic conductors)
Advanced polymer technique has the
potential to realize multifunctional
encapsulation in combination with 3D-silicon
technique and surface technology.
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THANK YOU
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