Dynamic wavelength add/drop multiplexer for UDWDM optical communication system
First Claim
1. A method of optical data transmission comprising;
- receiving an optical signal having a plurality of components, each component having a different wavelength;
receiving an information signal;
separating a first one of the components from the optical signal the first one being a CW carrier without optical modulation;
dropping a second one of the components from the optical signal as a drop optical signal while keeping a remainder of the optical signal;
modulating the first one of the components with the information signal to obtain a modulated component carrying a newly added signal from the information signal; and
combining the modulated component with the remainder of the optical signal to produce a new optical signal.
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Accused Products
Abstract
A method and device for optical add/drop is disclosed. The add/drop splits an input signal into two portions. The first portion is optically filtered to remove the channels, leaving an unmodulated carrier which is modulated with the newly added information. The second portion is split again into the through channels and a channel to be dropped. The dropped channel is detected or terminated and the through channels are recombined with the newly added channel to form an output optical signal. If desired, multiple channels may be dropped at the add/drop node. A dense wavelength division multiplexed (DWDM) optical communication system incorporating the add/drop node is also disclosed.
41 Citations
22 Claims
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1. A method of optical data transmission comprising;
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receiving an optical signal having a plurality of components, each component having a different wavelength;
receiving an information signal;
separating a first one of the components from the optical signal the first one being a CW carrier without optical modulation;
dropping a second one of the components from the optical signal as a drop optical signal while keeping a remainder of the optical signal;
modulating the first one of the components with the information signal to obtain a modulated component carrying a newly added signal from the information signal; and
combining the modulated component with the remainder of the optical signal to produce a new optical signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An add/drop node for an optical transmission system, comprising:
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an optical prefilter;
a first tunable optical filter in optical communication with the optical prefilter to receive an optical signal having a continuous wave carrier signal therefrom, the tunable filter being selectively tunable to transmit a selected pass band of the optical signal and to reflect a portion of the optical signal;
a modulator, configured and arranged to modulate the transmitted pass band from the first tunable filter with an information signal, the information being transmitted in a selected band;
a notch filter in optical communication with the first tunable optical filter to receive the reflected portion of the optical signal and being selectively tunable to transmit the reflected portion of the optical signal after filtering the continuous wave carrier therefrom to produce a filtered reflected optical signal;
a drop filter in optical communication with the the notch filter and configured and arranged to transmit a selected pass band of the filtered reflected optical signal as a drop optical signal and to reflect the remainder of the filtered reflected optical signal as a twice filtered reflected optical signal; and
a combiner in optical communication with the drop filter and configured and arranged to accept the twice filtered reflected optical signal and the modulated transmitted pass band and to transmit an output signal. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. An optical add/drop device, comprising:
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an optical input port to receive light having a CW carrier at a carrier frequency and a plurality of optical channels at channel frequencies different from the carrier frequency;
a first optical path comprising a bandpass optical filter to transmit light at the carrier frequency to produce a CW Light beam at the carrier frequency and reflect the optical channels, and an optical modulator to modulate the CW light beam to carry an add optical channel at a selected add channel frequency as a first output beam;
a second optical path comprising at least a first optical drop filter to select one of the optical channels to transmit as a first optical drop signal and to reflect other optical channels as a second output beam;
an optical router in optical communication with the optical input port, the first and the second optical paths to direct light from the optical input port to the first optical path and to direct reflected light from the first optical path to the second optical path; and
an optical combiner to combine the first and the second output beams into an output beam. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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Specification