View source for Optical modulation amplitude

In [[telecommunication]]s, '''optical modulation amplitude''' ('''OMA''') is the difference between two optical [[Power (physics)|power]] levels, of a [[Digital signal (electronics)|digital signal]] generated by an [[optical source]], ''e.g.,'' a [[laser diode]].

It is given by

:<math>\text{OMA} = P_1 - P_0 \, </math>

where ''P''<sub>1</sub> is the optical power level generated when the [[light]] source is "on," and ''P''<sub>0</sub> is the power level generated when the light source is "off."  The OMA may be specified in peak-to-peak [[Milliwatt|mW]].

The OMA can be related to the average power <math>P_{\text{av}} = (P_1+P_0)/2</math> and the [[extinction ratio]] <math>r_{e} = P_{1}/P_{0}</math>

:<math> \text{OMA} = 2 P_{\text{av}} \frac{r_{e}-1}{r_{e}+1}</math>

In the limit of a high extinction ratio, <math> \text{OMA} \approx 2P_{\text{av}} </math>.  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.

==External links==
*[https://grouper.ieee.org/groups/802/3/ae/public/nov00/ohlen_2_1100.pdf OMA presentation by Optillion, New Orleans, September 2000]

[[Category:Optical communications]]