The components are those that form the interface between optical and electronic signals and are used for optical signal transmission. This applies equally to visible light, UV light and infrared light.
Optoelectronics deals with electro-optical and magneto-optical phenomena and how these can be implemented in opto-electronic components; it deals with the emission, modulation and transmission of optical signals in optical networks and optical measurement technology.
Opto-electronic components include actuators that convert electrical sigbals into light and sensors that convert light into electrical signals. Optical actuators are laser diodes and light-emitting diodes, and optical sensors are photoresistors, photodiodes, phototransistors and photomultipliers. Other optoelectronic components include optocouplers, wavelength converters, optical amplifiers, optical switches, splitters, and optical multiplexers.
The terms optronics and photonics are often used interchangeably. However, there is a difference, which is expressed in the fact that components of optronics are supported by electronic functions, whereas photonic components are controlled exclusively by light pulses or wavelengths.