IEC 61280-2-9:2009 provides a parameter definition and a test method for obtaining optical signal-to-noise ratio (OSNR) using apparatus that measures the optical spectrum at a multichannel interface. Because noise measurement is made on an optical spectrum analyzer, the measured noise does not include source relative intensity noise (RIN) or receiver noise. Three implementations for an optical spectrum analyser (OSA) are discussed:
- a diffraction-grating-based OSA,
- a Michelson interferometer-based OSA,
- and a Fabry-Perot-based OSA.
This second addition cancels and replaces the first edition published in 2002 and constitutes a technical revision. The main changes from the previous edition are as follows:
- A paragraph has been added to the Scope describing the limitations due to signal spectral width and wavelength filtering;
- and Annex B has been added to further explain error in measuring noise level due to signal spectral width and wavelength filtering.