	US 7,596,320 B2
	Preemphasis of an optical wavelength multiplex signal
Erich Gottwald, Holzkirchen (Germany); and Lutz Rapp, Deisenhofen (Germany)
Assigned to Siemens Aktiengesellschaft, Munich (Germany)
Filed on Sep. 29, 2005, as Appl. No. 11/239,412.
Claims priority of application No. 10 2004 047 693 (DE), filed on Sep. 30, 2004.
Prior Publication US 2006/0067686 A1, Mar. 30, 2006
Int. Cl. H04J 14/02 (2006.01)

U.S. Cl. 398—94 [398/193; 398/197]

16 Claims

1. 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

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

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.