Patent ID: 7596320

Claim:
A method for preemphasizing an optical multiplex signal that comprises a plurality of signals having different wavelengths, transmitted by a transmitter by way of a plurality of substantially identical amplification sections to a receiver, comprising: determining on the transmitter a mean power level ( P_Tx(λ) Beginn ) and an optical power level spectrum (P_Tx(λ) Beginn ) for the optical multiplex signal; determining on the receiver an optical power level spectrum (P_Rx(λ) Beginn ) for the optical multiplex signal; determining the sum power levels for the multiplex signal at the input to and output from each amplification section, and determining mean gain values ( G i (λ) ) and mean attenuations ( a i (λ) ) for each amplification section from the measured values for the sum power levels of the multiplex signal; calculating a gain function (G link (λ)) which characterizes an overall gain of a transmission path from a relationship between optical power level spectra (P_Tx(λ) Beginn , P_Rx(λ) Beginn ) determined on the transmitter and the receiver; using the values G i (λ) and a i (λ) , calculating a wavelength-dependent function (Q(λ)) according to the specification Q ⁡ ( λ ) = ∑ i = 0 N ⁢ G link - i / ( N + 1 ) ⁡ ( λ ) · 〈 G i ⁡ ( λ ) 〉 · ∏ j = i + 1 N ⁢ 〈 G j ⁡ ( λ ) 〉 · 〈 a j ⁡ ( λ ) 〉 which serves to correct a new signal power level values (P_Tx(λ)) to be set on the transmitter, where j represents an auxiliary variable; and using the correction function Q(λ) and an effective noise figure (F eff (λ)), calculating the new signal power level values (P_Tx(λ)) to be set on the transmitter according to a formula P_Tx ⁢ ( λ ) = Q ⁡ ( λ ) · F eff ⁡ ( λ ) 〈 Q ⁡ ( λ ) · F eff ⁡ ( λ ) 〉 · 〈 P_Tx ⁢ ( λ ) Beginn 〉 so that signal-to-noise ratios for signals of the multiplex signal can be matched to one another at the receiver, wherein angle brackets represent a mean value for a value entered within them.