What is Photonics?

Photonics is the name given to the study and technology of the use of light (photons) for the transmission of information. The term was coined after the word ’electronics’, which is the study and technology of the use of electrons for the transmission of information.

A photon is a ’quantum’ of light, i.e. the smallest possible increment of electromagnetic energy, with some particle-like characteristics. Sunlight, for instance, is made of myriads of these tiny ’units’ of radiant energy called photons. A photon has no mass.

Photonics as a science studies the properties of photons and quantum interactions between photons and matter. It deals with the behavior and performance of photons in optical data transfer: light emission, transmission, modulation, deflection, amplification and detection.

Systems or devices are said to be ’photonic’ when they evidence at least one of the following properties:

• one (or more) essential port of the system/device responds to optical power, the system/device emits or modifies optical radiation,
• the system/device uses optical radiation for its internal operation.

Most of our current ’photonic’ systems or devices are in fact ’optoelectronic’, which means that signals are converted: an original input signal is received, converted, amplified (or reshaped or retimed or otherwise reconstructed) or simply transmitted. The process is often repeated, with electrons used to generate photons and vice-versa back and forth, to take better advantage of the characteristics of each signal. Complementary mechanical components are still very much in use.