Granted Patent B2

US 12,328,140 · App. 18/181,937 · Granted Jun 10, 2025

Inventors: Yangyang Fan (Beijing, CN); Zhenning Tao (Beijing, CN)

Assignee: Fujitsu Limited

H04B10/07953G01M11/333H04B10/07955

Abstract

Claims (30)

1. An apparatus to measure nonlinear damages in an optical link, comprising:

a memory; and

a processor coupled to the memory and to control execution of a process to,

generate respective multiple band-notch signals with different band-notch widths corresponding to a frequency point to be measured;

calculate respective multiple nonlinear noise-to-power ratios at the frequency point to be measured, according to the respective multiple band-notch signals obtained after the respective multiple band-notch signals with different band-notch widths pass through the optical link; and

extrapolate a real nonlinear noise-to-power ratio at the frequency point to be measured, according to the respective multiple nonlinear noise-to-power ratios corresponding to the respective multiple band-notch signals with different band-notch widths.

2. The apparatus according to claim 1 , wherein to calculate the respective multiple nonlinear noise-to-power ratios, the process is to:

measure multiple first depths of the respective multiple band-notch signals obtained after the respective multiple band-notch signals with different band-notch widths pass through the optical link at a transmit power satisfying a linear transmission condition;

measure multiple second depths of the respective multiple band-notch signals obtained after the respective multiple band-notch signals with different band-notch widths pass through the optical link at a transmit power to be measured; and

calculate the respective multiple nonlinear noise-to-power ratios at the frequency point to be measured according to the multiple first depths and the multiple second depths.

3. The apparatus according to claim 1 , wherein to generate the respective multiple band-notch signals, the process is to,

perform band-notch processing on a transmission signal in an I-path and Q-path respectively to generate a bilateral band-notch signal among the respective multiple band-notch signals; or perform band-notch processing on a complex signal to generate a unilateral band-notch signal among the respective multiple band-notch signals.

4. The apparatus according to claim 1 , the respective multiple band-notch signals are generated at the frequency point to be measured in a waveform domain or a symbol domain.

5. The apparatus according to claim 1 , wherein to generate the respective multiple band-notch signals, the process is to,

remove signals in a part of a range of frequency spectrum to generate a band-notch signal among the respective multiple band-notch signals; or

generate a band-notch signal, from among the respective multiple band-notch signals, by equal probability notch processing.

6. The apparatus according to claim 5 , to generate the band-notch signal by equal probability notch processing, the process is to,

make a probability distribution density of the band notch processed signal in a time domain close to or identical to a reference signal while producing a band notch at a spectrum;

construct signals of identical probability distribution densities by performing amplitude sorting, amplitude replacement and time sorting on the reference signal and an initialized seed signal;

construct an isospectral signal by slicing the spectrum and making total power within each slice equal to power of a corresponding reference signal slice; and

output the band-notch signal when a condition is satisfied.

7. The apparatus according to claim 1 , wherein the real nonlinear noise-to-power ratio is extrapolated at the frequency point to be measured under a dB unit or a linear unit.

8. The apparatus according to claim 1 , wherein,

for a dual-polarization signal, the process is to generate band-notch signals in two polarization states respectively, and calculate real nonlinear noise-to-power ratios of the two polarization states at the frequency point to be measured.

9. An apparatus to estimate performance of a nonlinear system, comprising:

the measurement apparatus for nonlinear damages in an optical link as claimed in claim 1 , to obtain real nonlinear noise-to-power ratios at frequency points to be measured;

a processor to control execution of a process to,

establish an equivalent additive noise model according to the real nonlinear noise-to-power ratios at the frequency points to be measured; and

estimate the performance of the nonlinear system according to the equivalent additive noise model.

10. An electronic device, including the apparatus as claimed in claim 1 .

Assignments (2)

Priority Claims (1)

Continuity (1)

References Cited (12)