Infrared vs. Visible Light vs. Ultraviolet: Key Differences

This page compares Infrared (IR), Visible Light (VL), and Ultraviolet (UV), highlighting their differences.

Introduction: All three are part of the electromagnetic spectrum, distinguished mainly by their unique frequencies and wavelengths. These bands are used in Optical Wireless Communication (OWC) systems such as LiFi, LiDAR, Free Space Optical (FSO) communication, and Optical Camera Communication (OCC).

Infrared (IR)

• Wavelength: 760 nm to 1 mm
• Communication Distance: Short and medium ranges in LiFi and OCC
• Advantages: Not visible to the human eye
• Disadvantages: Not always safe for humans. Line-of-sight (LOS) communication and very limited low data rate Non-LOS (NLOS) communication using reflection of infrared waves.
• Applications: LiFi, OCC (Optical Camera Communication), FSO (Free Space Optical) communication, LiDAR

Visible Light (VL)

The following are features of Visible Light Communication (VLC):

• VLC technology uses the visible light portion of the light spectrum.
• It uses a wavelength range from 380 nm to 750 nm (i.e., a frequency range from 430 THz to 790 THz) for communication.
• Data to be transmitted is modulated before transmission by modulating the light. A Power Amplifier (PA) is not needed, unlike RF communication.
• LEDs and lasers are used as transmitters or sources. Photodiode detectors are used as receivers.
• LiFi is one of the many applications of VLC.

Ultraviolet (UV)

• Wavelength: 10 to 400 nm
• Communication Distance: Short and medium ranges in LiFi
• Advantages: High data rate NLOS communication is possible, and it’s not visible to the human eye.
• Disadvantages: Not safe for humans.
• Applications: LiFi, FSO

Tabular Difference Between IR, VL, and UV

The following table summarizes the differences between IR, VL, and UV.

Reference: M. Z. Chowdhury et al.: Comparative Survey of Optical Wireless Technologies: Architectures and Applications