Control for periodic optical filter
First Claim
1. An apparatus for generating a control signal for at least one periodic filter arranged to filter the optical profile of a signal, at least one of the phase and the amplitude of the filter being tunable, the apparatus comprising:
- an optical waveguide for receiving a portion of said signal, an optical filtering means connected to said waveguide for filtering the received portion, and arranged to act as a first and second periodic filter, each having substantially the same period as the filter to be controlled, the phase between the periods of the first and second filters being a non-integer multiple of π
, and optical power measuring means arranged to measure the optical power of the signal transmitted by said optical filtering means.
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Accused Products
Abstract
The present invention relates to an apparatus for generating a control signal for at least one periodic filter arranged to filter the optical profile of a signal, at least one of the phase and the amplitude of the filter being tunable, the apparatus comprising an optical waveguide for receiving a portion of said signal, optical filtering means connected to said waveguide for filtering the received portion, and arranged to act as a first and second periodic filter, each having substantially the same period as the filter to be controlled, the phase between the periods of the first and second filters being a non-integer of π, and optical power measuring means arranged to measure the optical power of the signal transmitted by said optical filtering means. A method is also described for determining such a control signal. Such periodic filters can be used to flatten the gain profile of an optical amplifier.
9 Citations
18 Claims
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1. An apparatus for generating a control signal for at least one periodic filter arranged to filter the optical profile of a signal, at least one of the phase and the amplitude of the filter being tunable, the apparatus comprising:
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an optical waveguide for receiving a portion of said signal, an optical filtering means connected to said waveguide for filtering the received portion, and arranged to act as a first and second periodic filter, each having substantially the same period as the filter to be controlled, the phase between the periods of the first and second filters being a non-integer multiple of π
, andoptical power measuring means arranged to measure the optical power of the signal transmitted by said optical filtering means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An optical amplifier comprising an optical gain medium for amplifying optical signals, at least one periodic filter arranged to filter the optical profile of a signal, at least one of the phase and the amplitude of the filter being tunable, and an apparatus for generating a control signal for said period filter, the apparatus comprising
an optical waveguide for receiving a portion of said signal, optical filtering means connected to said waveguide for filtering the received portion, and arranged to act as a first and second periodic filter, each having substantially the same period as the filter to be controlled, the phase between the periods of the first and second filters being a non-integer of π - , and
optical power measuring means arranged to measure the optical power of the signal transmitted by said optical filtering means.
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11. A communications system comprising:
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an optical waveguide for receiving a portion of said signal, optical filtering means connected to said waveguide for filtering the received portion, and arranged to act as a first and second periodic filter, each having substantially the same period as the filter to be controlled, the phase between the periods of the first and second filters being a non-integer of π
, andoptical power measuring means arranged to measure the optical power of the signal transmitted by said optical filtering means. - View Dependent Claims (12)
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13. A method of generating a control signal for at least one periodic filter arranged to filter the optical profile of a signal, in which at least one of the phase and the amplitude of the filter are tunable, the method comprising:
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receiving a portion of the signal, performing a first optical filtering operation of filtering said signal by a first periodic filter having substantially the same period as the filter to be controlled, and measuring the optical power of the filtered signal, performing a second optical filtering operation of filtering the received signal by a second periodic filter having substantially the same period as the filter to be controlled, the second periodic filter being out of phase but not in antiphase with said first filter, and measuring the optical power of the filtered signal, and calculating the control signal from the power measurements performed in said first and second optical filtering operations. - View Dependent Claims (14, 15, 16, 17, 18)
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Specification