Data format for high bit rate wdm transmission
First Claim
1. A method of optically encoding data for transmission over a wavelength division multiplexed optical communications system comprising the steps of:
- generating a periodic series of optical pulses defining a series of time slots, wherein one pulse appears in each time slot;
filtering the pulses to produce carrier pulses extending over more than one time slot; and
modulating the pulses with data for transmission;
wherein the filter gives rise to the pulses having a temporal profile with a minimum substantially in the center of each of the time slots adjacent to the time slot for that pulse.
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Abstract
The invention includes a method for optically encoding data for transmission over a wavelength division multiplexed optical communications system comprising the steps of: generating a periodic series of optical pulses defining a series of time slots, wherein one pulse appears in each time slot; filtering the pulses to produce carrier pulses extending over more than one time slot; and modulating the pulses with data for transmission. Preferably, the filter gives rise to the pulses having a temporal profile with a minimum in the centre of each of the time slots adjacent to the time slot for that pulse. The resulting data format allows for greater spectral efficiency in a WDM optical transmission system as compared with conventional RZ and NRZ data formats.
22 Citations
9 Claims
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1. A method of optically encoding data for transmission over a wavelength division multiplexed optical communications system comprising the steps of:
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generating a periodic series of optical pulses defining a series of time slots, wherein one pulse appears in each time slot;
filtering the pulses to produce carrier pulses extending over more than one time slot; and
modulating the pulses with data for transmission;
wherein the filter gives rise to the pulses having a temporal profile with a minimum substantially in the center of each of the time slots adjacent to the time slot for that pulse. - View Dependent Claims (3, 4, 5, 7, 8, 9)
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2. (canceled)
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6. A transmitter for producing an optical data signal for transmission over a wavelength division multiplexer optical communication system comprising:
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means for producing a periodic series of optical pulses defining a series of time slots, wherein one pulse appears in each time slot;
a filter having a spectral profile giving rise to pulses with a temporal profile extending over more than one time slot, the temporal profile having a minimum substantially in the center of each of the time slots adjacent to the time slot for that pulse; and
modulating means for modulating the pulses with data for transmission.
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Specification