What the different between LED and Laser Light Source?

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As
the wide application of fiber optic system,
optical light source plays a more and more important part in it. We
known a basic optical fiber system consists of a transmitter, an optical fiber
and a receiver. The fiber optic light source, as an important component of the
transmitter is modulated by a suitable drive circuit in accordance with the
signals to be transmitted. Optical light source is also needed for performing
fiber optic network testing to measure the fiber optic loss in the cable plant.
Light source is offered in a variety of types including LED, halogen and laser.
Among which, LED and Laser light source are two types of semiconductor light
sources. The following article will discuss about laser vs LED and list the
differences between laser and Led light source.

 

Basically,
both kind of light source must be able to turn on and off millions to billions
of times per second while projecting a near microscopic beam of light into an
optical fiber. During the working process of optical signals, they are both
supposed to be switched on and off rapidly and accurately enough to properly
transmit the signals.

 

Laser
vs LED: Difference in Speed, Transmitting Distance & Cost

The
general difference between them as that LEDS is the standard light source which
is short for light-emitting diodes. Laser light source like gas lasers may be
mainly used in some special cases. Lasers are more powerful and operate at
faster speeds than LEDs, and they can also transmit light farther with fewer
errors. Laser are also much more expensive than LEDs.

 

Laser
vs LED: Difference in Structure

LED
fiber optic light source isf

 

870
nm are usually

made
of materials that influence the wavelengths of light that are emitted. A basic
LED light source is a semiconductor diode with a p region and an n region. When
the LED is forward biased, current flows through the LED. As current flows
through the LED, the junction where the p and n regions meet emits random
photons. LEDs emitting in the window of 820 to 870 nm are usually gallium
aluminum arsenide (GaAIAs). Laser is also a semiconductor diode with a p and an
n region like LED, but it provides stimulated emission rather than the simplex
spontaneous emission of LEDs. The main difference between a LED and a laser is
that the laser has an optical cavity required for lasting. The cavity is formed
by cleaving the opposite end of the chip to form highly parallel, reflective,
mirror-like finishes.

 

What
is VCSEL?

VCSEL,
known as vertical-cavity surface-emitting laser, is a popular laser source for
high speed networking, which consists of two oppositely-doped Distributed Bragg
Reflectors (DBR) with a cavity layer. It combines high bandwidth with low cost
and is an ideal choice for the gigabit networking options. The idea for
vertical light emitting laser started between 1975-1977 to satisfy the
planarization constraints of the integrated photonics according to the
microelectronic technology available then. Nowadays, apart from the application
in optical fiber data transmission, it is also widely used for other
applications like analog broadband signal transmission, absorption spectroscopy
(TDLAS), laser printers, computer mouse, biological tissue analysis, chip scale
atomic clock, etc.

 

Conclusion

Different
wavelengths travel through a fiber at different velocities as a result of
material dispersion. What should always keep in mind is that both Laser and LED
will not emit a single wavelength, but a range of wavelength that is known as
the spectral width of the source. Fiber optic light source is always working
with the fiber optic power meter. During the working process, it collimates
beams of light and aim right down the center of the narrow single mode core and
propagates in essentially a single mode transmission. For more questions about
fiber optic test equipment, such as visual fault locators, optical power meter,
OTDR testers, etc., please go for fiber-mart.com.