MODULE : 5
CHAPTER : 2
PHOTONICS
Introduction
Photonics is the science of light. It is the physical science of light generation,
detection, and manipulation through emission, transmission, modulation, signal
processing, switching, amplification, and sensing.
What is photonics used for
It is the technology of generating, controlling, and detecting light waves and
photons, which are particles of light. The characteristics of the waves and
photons can be used to explore the universe, cure diseases, and even to solve
crimes.
Photonic devices
Photonic devices are components for creating, manipulating or detecting
light. This can include laser diodes, light-emitting diodes, solar and photovoltaic
cells, displays and optical amplifiers.
The unique characteristics of photonic devices create an additional dimension
energy saving and larger communication distances. In addition, photonic
devices are less sensitive to interference and have unique physical
characteristics.
ENGINEERING PHYSICS PHT-100/110 | MOHAMMED JANISH K – ASST. PROFESSOR | MEA ENGINEERING COLLEGE | PERINTHALMANNA | 9995831836 1
, Light-Emitting Diodes
LED is a semiconductor p-n junction diode used to
convert electrical energy in to light energy under
forward bias condition.
During forward bias condition the electrons from N-
side and holes from P-side enter in to the depletion
layer.
In depletion region holes and electrons recombine each other, during this
recombination the excess energy of electron is emitted as electromagnetic
radiation (light).
The color of the light
(corresponding to the energy of
the photons) is determined by
the energy required for electrons
to cross the band gap of the
semiconductor
The emitted energy hν=Eg (Band
gap energy)
LEDs have many advantages over incandescent light
lower energy consumption
longer lifetime
improved physical robustness
smaller size
and faster switching
ENGINEERING PHYSICS PHT-100/110 | MOHAMMED JANISH K – ASST. PROFESSOR | MEA ENGINEERING COLLEGE | PERINTHALMANNA | 9995831836 2
CHAPTER : 2
PHOTONICS
Introduction
Photonics is the science of light. It is the physical science of light generation,
detection, and manipulation through emission, transmission, modulation, signal
processing, switching, amplification, and sensing.
What is photonics used for
It is the technology of generating, controlling, and detecting light waves and
photons, which are particles of light. The characteristics of the waves and
photons can be used to explore the universe, cure diseases, and even to solve
crimes.
Photonic devices
Photonic devices are components for creating, manipulating or detecting
light. This can include laser diodes, light-emitting diodes, solar and photovoltaic
cells, displays and optical amplifiers.
The unique characteristics of photonic devices create an additional dimension
energy saving and larger communication distances. In addition, photonic
devices are less sensitive to interference and have unique physical
characteristics.
ENGINEERING PHYSICS PHT-100/110 | MOHAMMED JANISH K – ASST. PROFESSOR | MEA ENGINEERING COLLEGE | PERINTHALMANNA | 9995831836 1
, Light-Emitting Diodes
LED is a semiconductor p-n junction diode used to
convert electrical energy in to light energy under
forward bias condition.
During forward bias condition the electrons from N-
side and holes from P-side enter in to the depletion
layer.
In depletion region holes and electrons recombine each other, during this
recombination the excess energy of electron is emitted as electromagnetic
radiation (light).
The color of the light
(corresponding to the energy of
the photons) is determined by
the energy required for electrons
to cross the band gap of the
semiconductor
The emitted energy hν=Eg (Band
gap energy)
LEDs have many advantages over incandescent light
lower energy consumption
longer lifetime
improved physical robustness
smaller size
and faster switching
ENGINEERING PHYSICS PHT-100/110 | MOHAMMED JANISH K – ASST. PROFESSOR | MEA ENGINEERING COLLEGE | PERINTHALMANNA | 9995831836 2
