Method and system for optimizing the pulse form of an amplitude modulated optical signal
View Patent ↗The influences on transmission quality caused by chirp and self-phase modulation are at least largely corrected by way of an optimally set operating point of the modulator ( 2 ). Suitable criteria are obtained in control loops in order to maintain the optimal setting.
1. A method for optimizing an amplitude-modulated optical signal, comprising the steps of:
generating said amplitude-modulated optical signal in a modulator by modulating an optical signal with a digital signal;
feeding said amplitude-modulated optical signal to a frequency discriminator which outputs a spectral distribution signal;
feeding said spectral distribution signal to a control device which is also fed an adjustable reference signal; and
generating a control signal which sets an operating point of said modulator by comparing said adjustable reference signal and said spectral distribution signal.
2. The method as claimed in claim 1 , further comprising the step of separating a measuring signal which is fed to said frequency discriminator from said amplitude-modulated optical signal.
3. The method as claimed in claim 1 , further comprising the steps of:
determining said spectral distribution signal at a start of a transmission path; and
setting said reference signal based on properties of said transmission path.
4. The method as claimed in claim 1 , further comprising the steps of:
determining said spectral distribution signal at a receiving end; and
transmitting said spectral distribution signal or a control signal generated therefrom to said modulator provided at a transmitting end.
5. The method as claimed in claim 1 , wherein said control signal is obtained during periodically occurring time windows.
6. An arrangement for optimizing an amplitude-modulated optical signal, comprising:
a light source;
a modulator having an output, said modulator being fed an optical signal from said light source and a digital signal for amplitude modulation;
a frequency discriminator which outputs a spectral distribution signal that is connected to said output of said modulator via a splitter; and
a control device with a reference signal setting device which is fed said spectral distribution signal and which generates a control signal which controls an operating point of said modulator.
7. The arrangement as claimed in claim 6 , further comprising an adder which is fed said control signal and said digital signal, an adder output being fed to a modulation input of said modulator.