Optical modulation amplitude
Encyclopedia
In telecommunication
s, optical modulation amplitude (OMA) is the difference between two optical power
levels, of a digital signal
generated by an optical source, e.g., a laser diode
.
It is given by
where P1 is the optical power level generated when the light
source is "on," and P0 is the power level generated when the light source is "off." The OMA may be specified in peak-to-peak mW.
The OMA can be related to the average power
and the extinction ratio 
In the limit of a high extinction ratio,
. However, OMA is often used to express the effective usable modulation in a signal when the extinction ratio is not high and this approximation may not be valid.
Telecommunication
Telecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded...
s, optical modulation amplitude (OMA) is the difference between two optical power
Power (physics)
In physics, power is the rate at which energy is transferred, used, or transformed. For example, the rate at which a light bulb transforms electrical energy into heat and light is measured in watts—the more wattage, the more power, or equivalently the more electrical energy is used per unit...
levels, of a digital signal
Digital signal
A digital signal is a physical signal that is a representation of a sequence of discrete values , for example of an arbitrary bit stream, or of a digitized analog signal...
generated by an optical source, e.g., a laser diode
Laser diode
The laser diode is a laser where the active medium is a semiconductor similar to that found in a light-emitting diode. The most common type of laser diode is formed from a p-n junction and powered by injected electric current...
.
It is given by
where P1 is the optical power level generated when the light
Light
Light or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...
source is "on," and P0 is the power level generated when the light source is "off." The OMA may be specified in peak-to-peak mW.
The OMA can be related to the average power
and the extinction ratio In the limit of a high extinction ratio,
. However, OMA is often used to express the effective usable modulation in a signal when the extinction ratio is not high and this approximation may not be valid.