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Difference Between LED And Laser Diode

The important distinction between LED and LASER lies in the operating theory. LED emits light as a consequence of the recombination of charge carriers around P-N Junction.

Whereas, LASER emits light as a result of photons entering the atom, which forces them to unleash identical photons. The laser acts on the theory of stimulated emission and the LED functions on the principle of electro-luminance.

Speaking of LEDs, they have multiple wavelengths and are polychromatic. They can also appear to generate just a single color while producing a number of wavelengths.

Via laser light diodes, real single wavelengths are released. And this is the basic distinction between how LEDs and lasers operate and are used in different applications, contributing to a host of other variations.

Here now in this article we will be comparing as well as describing the differences between LED and Laser Diode.  

LED

For different key uses, the LED is known as the optical source. Electro-luminance is the key concept behind its operation. In this process, as electrons and holes meld at the junction, the forward biased P-N junction emits photons.

The LED is a junction diode that controls the amount of electricity to flow through it. An LED is made from semiconducting compounds containing gallium and other materials to produce different colored light energy.

Gallium, indium, and nitrate compounds contain blue and green LEDs. Gallium, aluminium, and phosphate compounds, on the other hand, create red LEDs.

LEDs are an incredibly inexpensive and handy light source. Due to their low performance strength, they are typically used for multi-mode fibers. They are used up to a speed of around 30 Mbps in low data rate optical transmission networks, where it is not a major issue to scatter output pulses because of dispersion.

Laser Diode

Difference Between LED And Laser Diode

The LASER is working under the theory of stimulated radiation emitted. It is thus termed Light Amplification by Radiation Stimulated Emission. By hitting the atom with the same electron, the stimulated emission is the emission of the photon.

When electrical energy is supplied to the electron at the lower power frequency, the extra energy delivered to it will be consumed by the leap from the valence band to the conduction band. The process is known as “Absorption.”

Laser diodes are made of gallium arsenide phosphide and are used in fiber optic systems. A laser with a sand grain size will generate a power output of around 10mWatt.

Laser ON/OFF turn speeds are higher than LEDs. The spectral spread is around 1 to 2 nm or much smaller than the LED. Consequently, laser dispersion is not a concern relative to LEDs. Lasers are also more suited for the monomodal and high bit rate devices used for optical fiber systems.

These days, people never think about throwing a party without a laser lighting system. The laser lights are quite popular as party lights.

Major Difference Between LED and Laser Diode

  1. A main distinction between LED and LASER is also provided by the light beam emitted by LED and LASER. The light produced by the LED consists of different colors, while a single color is the light beam created by the LASER.
  2. Significant variations were also created by the working concept of LED and LASER. The LED acts solely on the electro-luminance principle, which implies electron luminance. On the other side, LASER acts on the spontaneous emission principle.
  3. Electrical to optical efficiency for LEDs is 10-20% where laser efficiency is up to 70%.
  4. LED requires limited applied bias and works at comparatively low levels of current. But high driving power is necessary for the laser and high injection current density is required.
  5. The junction area is the other main distinction between LED and LASER. In the case of the LASER, the field of the junction is very small and, in the case of the LASER, light is allowed to enter from a very small area. The LED junction field, on the other hand, is broader. Light is therefore permitted to travel across a large field.
  6. In LEDs and lasers, the distribution of charge carriers such as electrons and holes is also distinct. The concentration is very high for the laser, although it is very low in LED. Laser is therefore used in the medical field in the surgical instrument when it has such energy that it can also cut the material in contact with it.

Pros and Cons of LED And Laser Diode

As you already understood that there are so many significant differences between LED and laser diodes, so it is obvious there will be some possible pros and cons of both the lighting systems. 

LEDs are also cheaper for generating and preserving both. That is why they are used to providing light in regular commercial and household environments. At just around 50mAh, LEDs can emit lights. 

Lasers are more difficult to manage and run. To sustain the elevated energy state of electrons, lasers need a higher current. It is important that the current should be above the 40mAh threshold minimum. 

The precise equipment that emits the light beam will erode the high power performance of lasers, making their application extremely specialized, such as for fiber optics. LEDs emit scattered light for contrast, but if the LED reflects over 1 mm square, a laser will focus on a square of only 10 microns.

Among these two lighting technology, LED has a longer lifespan. 

Final Words 

As you already came to know, LED and Laser Diode are designed quite similarly but they also have so many differences in their characteristics and applications.

As a consequence of substrate dispersion, various wavelengths pass through a fibre at different velocities. 

One thing that should be kept in mind is - not a single wavelength can emit both laser and LED, but a wavelength range that is known as the source spectral diameter.

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