Optoelectronic Devices

In an increasingly connected and technologically advanced world, optoelectronic devices have emerged as key players in shaping our future. Combining the principles of optics and electronics, these devices have revolutionized various industries by enabling faster communication, high-resolution imaging, energy-efficient lighting, and more.

Introduction

As the name suggests, optoelectronic is the mix of two technologies: optics (light or photons) and electronics (electrons). Optoelectronic is the technology of electronic devices related to optics (light). The light is emitted, modified, or converted (as in electrical-to-optical or optical-to-electrical). Optoelectronic devices involve electronic components that are activated or deactivated based on the intensity of light. These devices can provide services in various fields, including but not limited to military, telecommunications, and medicine.

The properties of optoelectronic devices are listed below:

Working Principle of Optoelectronic Communication System

A typical optoelectronic communication system consists of components, namely:

Light Source

The light emitted from the source acts as an input to the Optical Transmitter. Depending upon the application, LEDs and Laser Diodes are the light sources. They generate input electrical signals for the communication system.

Optical Transmitter

The Optical Transmitter converts the signal received from a Laser Diode or LED to an optical output.

Photo Coupler

The Photo Couplers transfer the electrical signals between two isolated circuits through the transmission channel, which may be an optical fiber, waveguide, or free space. It also provides high insulation voltage.

Optical Fiber, Waveguide

It acts as a transmission medium and guides electromagnetic waves in the optical spectrum.

Transducer

Transducer modulates the signal proportional to the incident light, and the signal further undergoes coupling through the channel.

Optical Receiver or Detector

Photodiodes and Phototransistors are generally used as Optical Detectors. The light detector converts the incident light into an electrical signal, which is further processed or stored to receive information. The electrical signal generated is either a Photo-current or a Photo-voltage.

Types of Optoelectronic devices — **Types of Optoelectronic Devices**

An optoelectronic device is an electronic device involving light. (Source: Lumenci)

1. Light Emitters

These devices emit light when excited electrically (i.e., these devices convert electrical energy into optical radiations). They are also known as light sources. Examples – LED, Laser diode, etc.

Light Emitting diode (LED) - LED is a p-n junction diode. It is a specially doped diode made up of a particular type of semiconductor. When the light emits in the forward biased, it is called an LED.
IR – An optoelectronic device that emits non-coherent optical radiation at a photon energy close to the bandgap of the junction.
LASER – Light amplification by stimulated emission radiation. A process that emits optical radiation which is coherent, highly directional, and nearly monochromatic.

2. Light Detectors or Sensors

These devices convert light into some form of electrical energy. Examples – LDR, Photodiode, Phototransistor, Solar cell, etc.

a) Photodetector

(I) Photovoltaic

The generation of voltage or electric current in a substance because of exposure to light is known as the photovoltaic effect.

(ii) Photoconductive

Devices that change their resistance upon exposure to incident radiation are called photo-conducting devices. When operated in the photoconductive mode, Junction devices utilize the reverse characteristic of a PN junction.

(iii) Photodiode

An optoelectronic device based on a semiconductor junction that absorbs light and converts the light input to a current. A photodiode is a PN-junction diode that converts light energy into electricity.

PN Photodiode: The photodetection occurs within the depletion area of the diode. As this is relatively small, the sensitivity could be better for some other photodiode forms.
PIN Photodiode is a photodetector in which the depletion layer thickness can be modified to generate a large photocurrent. If the thickness of the depletion layer is more, then the surface area on which light is falling also increases. Due to this, the conversion efficiency of a photodiode increases, and more photocurrents will generate.
Avalanche Diode – An avalanche photodiode is one kind of semiconductor device specially designed to work in the reverse breakdown region.

Avalanche Diode – An avalanche photodiode is one kind of semiconductor device specially designed to work in the reverse breakdown region.
Phototransistors – It is a device almost like an ordinary junction transistor. However, the only variation is a large area of the base-collector region. In phototransistors, the base current is not supplied as input; instead, light energy is provided to trigger the transistor. This supplied light energy generates an electric current through the device due to the photoelectric effect.

Bulk effect photoconductors have no junction.

The four materials typically employed in photoconductive devices are Cadmium Sulphide (CdS), Cadmium Selenide (CdSe), lead sulfide (PbS), and Thallium Sulphide (TlSIn).

b) Photoemissive: these devices are based on the photoelectric effect, in which incident photons release electrons from the surface of detector material. The free electrons are then collected in an external circuit.

3. Optocouplers or Optoisolators

These devices are formed by combining a light source and light detector into one device. Optocouplers will couple the signal from one point to another but isolate them physically.

Optoelectronics Market Outlook

Conclusion

Optoelectronic devices have brought about transformative changes across numerous industries, from communication and healthcare to energy and lighting. Their ability to convert electrical signals into optical signals, and vice versa, has enabled faster data transfer, more vibrant displays, and energy-efficient lighting solutions. As technology continues to advance, optoelectronic devices will play an increasingly vital role in shaping the future, contributing to innovations in photonics, nanotechnology, IoT, and sustainable solutions. Embracing the potential of these devices will propel us toward a brighter, more connected, and more sustainable world.

Disclaimer: This report is based on information that is publicly available and is considered to be reliable. However, Lumenci cannot be held responsible for the accuracy or reliability of this data.

Introduction

Working Principle of Optoelectronic Communication System

Optoelectronics Market Outlook

Conclusion

Author

Editorial Team at Lumenci