Laser Diode

Laser diodes can produce a narrow beam of laser light in which all the light waves have similar wavelengths. Because of this property, laser beams are very bright and can be focused over a very tiny spot.
Laser diodes are widely used in various devices like barcode readers, laser printers, security systems, fibre optic communications etc. In this article, we will learn about the types, characteristics and applications of laser diodes.

• What Is a Laser Diode?
• Types of Laser Diodes
• Characteristics of Laser Diode
• Applications of Laser Diode
• Advantages of Laser Diode
• Disadvantages of Laser Diode
• Frequently Asked Questions – FAQs

What Is a Laser Diode?

A laser diode is a semiconductor that uses a p-n junction for producing coherent radiation with the same frequency and phase, which is either in the visible or infrared spectrum. It is also called an injection laser diode and the technology is similar to that found in LED.

Types of Laser Diodes

The following are the types of laser diodes:

• Double heterostructure laser diode: Heterostructure is a material that is sandwiched between two n-type and p-type materials. Because of the presence of heterostructure material, this type of laser diode is called a double heterostructure (DH) laser diode. The main advantage of this diode is that the active region is used for better optical amplification.
• Quantum well laser diode: The quantum well is a very thin middle layer in the diode. The quantum energy is used for converting electrons from higher energy to lower energy and is responsible for better efficiency.
• Separate confinement heterostructure laser diode: There are two additional layers along with three layers. These layers have a lower refractive index and the emission of light is also improved.
• Vertical cavity surface-emitting laser diode: In this type of laser diode, the optical cavity is along the axis of the current flow.

Learn more about types of diodes here.

Characteristics of Laser Diode

The laser diode is characterized as follows:

• Monochromatic: An insubstantial width of radiated narrow light containing only a single color.
• Well-directed: In this type, the light will be directed into a narrow beam. It is easy to launch through an optical fibre.
• Coherent: A light with a single wavelength emitted by an LED with a wide wavelength.
• The important characteristic of a laser diode is its approach or the threshold. The laser diode doesn’t operate until a minimum power is applied. If the light is below its energy, then the emission is weaker than the threshold compared to the full energy.

Read More: Optical Fibre

Applications of Laser Diode

The following are the applications of laser diodes:

• Consumer electronics: This includes laser printers, CDs and DVD players, and fibre optic communication.
• Industrial applications: When it comes to industrial applications, laser diode is preferred as it is a source of a high-intensity laser beam and used for cutting, drilling, welding, etc.
• Medical applications: Laser diodes are used for the elimination of unwanted tissues and tumours and also in dental medication.
• Scientific instrumentation: Instruments like spectrometers, range finders, contact-less measurements can be done with the help of laser diodes.
• The laser diode in telecom: Laser diodes with 1.3 μm and 1.55 μm bands are used as the main source of light in telecom and as the band changes laser diodes find application in optical amplification.

Learn about uses of diodes here.

Advantages of Laser Diode

The following are the advantages of laser diode:

• When a laser diode is compared with other light-emitting devices, the operational power is less in the laser diode.
• The handling of these diodes is easy as they are small.
• The light generated by these diodes is of high efficiency.

Disadvantages of Laser Diode

The following are the disadvantages of laser diode:

• These diodes are expensive when compared to other light-emitting devices.
• The light generated by these diodes adversely affects the eyes.

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Frequently Asked Questions – FAQs

What is a laser diode?

A laser diode is a semiconductor that uses a p-n junction for producing coherent radiation with the same frequency and phase which is either in the visible or infrared spectrum. It is also called an injection laser diode and the technology is similar to that found in LEDs.

What are the advantages of laser diodes?

• When the laser diode is compared with other light-emitting devices, the operational power is less in the laser diode.
• The handling of these diodes is easy as they are small.
• The light generated by these diodes is of high efficiency.

What is a quantum well laser diode?

The quantum well is a very thin middle layer in the diode. Quantum energy is used for converting electrons from higher energy to lower energy and is responsible for better efficiency.

What are infrared rays?

Infrared waves are also referred to as heat or thermal waves. This is because they have a heat-inducing property.

What are the disadvantages of laser diodes?

• These diodes are expensive when compared to other light-emitting devices.
• The light generated by these diodes adversely affects the eyes.

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