Using superimposed ASK label in an all-optical label swapping system and method thereof
An all-optical label swapping system and method superimposes a low-speed ASK label on top of a high-speed DC-balanced-line-coded ASK payload. An old ASK label is erased by modulating the combined payload and label signal with the inverse of the received ASK label. This ASK labeling technique requires only low speed external modulators and low speed optical receivers to perform the label swapping mechanism, and does not require sophisticated optical components.
1. A method for swapping, in an optical label swapping system having a splitter, data transmitted in high-speed packet switching networks, comprising the step of:
receiving, in the optical label swapping system, data containing a payload and a header superimposed in the payload;
splitting said data in the splitter into first data and second data;
low-pass filtering said first data to obtain a first header;
inverting said first header;
modulating said inverted first header and said second data to erase a second header of said second data;
adding a new header to said second data whose said second header is erased to form new data; and
outputting said new data.
2. The method of claim 1 , wherein said header has a modulation depth of about 22% relative to a modulation depth of said payload.
3. The method of claim 1 , wherein the low-pass filtering is performed in a low-pass filter of the optical label swapping system.
4. A system for optical-label-swapping data transmitted in high-speed packet switching networks, said data containing a payload and a header superimposed in the payload, the system comprising:
a splitter, splitting said data into first data and second data;
a low pass filter, low-pass filtering said first data to obtain a first header;
a limiting amplifier, inverting said first header;
a first modulator, modulating said inverted first header and said second data to erase a second header of said second data; and
a second modulator, adding a new header to said second data whose said second header is erased to form new data.
5. The system of claim 4 , further comprising a limiting amplifier for amplifying said first header.
6. The system of claim 5 , further comprising a transmitter filter for reshaping said first header after amplifying.
7. The system of claim 4 , further comprising a photodiode for receiving said first data to the low pass filter.
8. The system of claim 4 , wherein said header superimposed in the payload has a modulation depth of about 22% relative to a modulation depth of said payload.