Method for measuring the performance of broadband dense wavelength division multiplexer (DWDM) using non-linear iterative algorithm

A method for detecting signal channels in a wavelength-multiple d optical signal, comprising the steps of:

• obtaining raw signal power of an optical signal over a predetermined range of wavelengths;
• providing initially estimated channels within the predetermined range of wavelengths based upon the raw signal power;
• assigning initial power levels respectively to the initially estimated channels;
• providing a scanning filter characteristic;
• performing a first nonlinear deconvolutional algorithm with a first iteration and at least a second iteration subsequent to the first iteration for each of the initially estimated channels to obtain a power spectrum of the signal, the step of performing the first nonlinear deconvolutional algorithm comprising the steps of:
• providing a constant relaxation factor;
• within the first iteration,
• performing a convolutional operation on the scanning filter characteristic and the initial power level to obtain a first convolved result;
• subtracting the first convolved result from the raw signal power to obtain a first error;
• multiplying the first error by the constant relaxation factor to obtain a first correction quantity;
• and
• adding the first correction quantity to the initial power level to obtain a second power level;
• and
• within the second iteration,
• performing a convolutional operation on the scanning filter characteristic and the second power level to obtain a second convolved result;
• subtracting the second convolved result from the raw signal power to obtain a second error;
• multiplying the second error by the constant relaxation factor to obtain a second correction quantity;
• and
• adding the second correction quantity to the second power level to obtain a third power level;
• determining peak power levels of the signal in the initially estimated channels from the power spectrum;
• and
• determining whether signal channels exist based upon the peak power levels in the initially estimated channels.

A method for determining channel characteristics of a wavelength-multiplexed optical signal, comprising the steps of:

• obtaining raw signal power of an optical signal over a predetermined range of wavelengths;
• providing initially estimated channels within the predetermined range of wavelengths based upon the raw signal power;
• assigning initial power levels respectively to the initially estimated channels;
• providing a scanning filter characteristic;
• performing a coarse nonlinear iterative deconvolutional algorithm for each of the initially estimated channels based upon the initial power levels, the raw signal power and the scanning filter characteristic to obtain a power spectrum of the signal;
• determining peak power levels of the signal in the initially estimated channels from the power spectrum;
• determining whether signal channels exist based upon the peak power levels in the initially estimated channels;
• and
• performing a fine nonlinear iterative deconvolutional algorithm with a first iteration and at least a second iteration subsequent to the first iteration for each of the signal channels, the step of performing the fine nonlinear iterative deconvolutional algorithm comprising the steps of:
• within the first iteration,
• providing a first relaxation factor;
• performing a convolutional operation on the scanning filter characteristic and the peak power level to obtain a first convolved result;
• subtracting the first convolved result from the raw signal power to obtain a first error;
• multiplying the first error by the first relaxation factor to obtain a first correction quantity;
• and
• adding the first correction quantity to the peak power level to obtain a refined power level;
• and
• within the second iteration,
• providing a second relaxation factor less than the first relaxation factor;
• performing a convolutional operation on the scanning filter characteristic and the refined power level to obtained a second convolved result;
• subtracting the second convolved result from the raw signal power to obtain a second error;
• multiplying the second error by the second relaxation factor to obtain a second correction quantity;
• and
• adding the second correction quantity to the refined power level to obtain a further refined power level.