FIELD: optics.
SUBSTANCE: invention relates to fibre-optic communication, particularly to efficiency estimation in fiber-optic communication lines, and more specifically to OSNR margin measurement procedure in communication line with DWDM spectral multiplexing and FEC error correction signal coding. For this, in OSNR margin measurement method, including following stages: before putting communication line into operation OSNRBTB value is measured and OSNR dependence from BER in circuit with test short line without FEC errors correction, during communication line putting into operation OSNROSA1 value is measured at communication line end, during operation periodical measurements of communication line parameters are made, based on the values of which taking into account the values of parameters measured before putting the communication line into operation, the reserve OSNRM by OSNR, OSNR dependence on BER is presented in the form of polynomial of second degree: OSNR=a0+a1log(BER)+a2 (log(BER)2), where a0, a1 and a2 - second-degree polynomial coefficients approximating the experimentally measured dependence of OSNR on BER in the test line, when the communication line is put into operation on its section until FEC errors are corrected, measuring the error coefficient BER1, during operation of a communication line on its section until FEC errors are corrected, mean value of error coefficient BER2 is measured periodically and value OSNRM is calculated from value of measured values by OSNR.
EFFECT: technical result consists in simplification of OSNR margin measurement in communication line with spectral seal.
1 cl, 1 tbl, 2 dwg
