Editing Bandwidth (signal processing) (section)

== Photonics ==

In [[photonics]], the term ''bandwidth'' carries a variety of meanings:
*the bandwidth of the output of some light source, e.g., an ASE source or a laser; the bandwidth of ultrashort optical pulses can be particularly large
*the width of the frequency range that can be transmitted by some element, e.g. an optical fiber
*the gain bandwidth of an optical amplifier
*the width of the range of some other phenomenon, e.g., a reflection, the phase matching of a nonlinear process, or some resonance
*the maximum modulation frequency (or range of modulation frequencies) of an optical modulator
*the range of frequencies in which some measurement apparatus (e.g., a power meter) can operate
*the [[Bit rate|data rate]] (e.g., in Gbit/s) achieved in an optical communication system; see [[bandwidth (computing)]].

A related concept is the [[spectral linewidth]] of the radiation emitted by excited atoms.