Grating assisted acousto-optic tunable filter and method
First Claim
1. A tunable acousto-optic filter tunable across substantially the entire EDFA passband and receiving light from a source and providing plural available light wavelength channels for selective output, said filter comprising:
- an acousto-optic beam deflector having a variable control signal input for selectively deflecting received light, light deflection angle being variable by operation of said control signal input;
a grating having a grating vector orientation transverse to propagation direction of light from said acousto-optic beam deflector for wavelength dependent dispersion of light deflected at said acousto-optic beam deflector to provide a resolution enhanced spectrum of available output channels in an output plane; and
at least a first fixed output location at said output plane for output thereat of at least a first selected one of said output channels shifted to said output location by operation of said acousto-optic beam deflector.
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Abstract
An acousto-optic tunable filter and filtering method are disclosed providing for a significantly increased number of available wavelength channels for output. The filter combines a diffraction grating, the grating vector of which is transverse to light propagation direction, with an acousto-optic beam deflector, which, by accommodating a narrow spectral bandwidth (about 5% that of conventional acousto-optic tunable filters), provides significantly increased output bandwidth and available wavelength channels (by a factor of approximately 20).
71 Citations
20 Claims
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1. A tunable acousto-optic filter tunable across substantially the entire EDFA passband and receiving light from a source and providing plural available light wavelength channels for selective output, said filter comprising:
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an acousto-optic beam deflector having a variable control signal input for selectively deflecting received light, light deflection angle being variable by operation of said control signal input; a grating having a grating vector orientation transverse to propagation direction of light from said acousto-optic beam deflector for wavelength dependent dispersion of light deflected at said acousto-optic beam deflector to provide a resolution enhanced spectrum of available output channels in an output plane; and at least a first fixed output location at said output plane for output thereat of at least a first selected one of said output channels shifted to said output location by operation of said acousto-optic beam deflector. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A tunable acousto-optic filter tunable across substanitally the entire EDFA passband and receiving light from a source and providing plural available light wavelength channels for selective output, said filter comprising:
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an optical deflector assembly including a variable rf control signal input for selectively deflecting received light, deflection angle being variable responsive to frequency of signal applied at said rf control signal input; and a diffraction grating characterized by grating vector orientation transverse to light propagation direction for wavelength dependent dispersion of light deflected at said optical deflector assembly to provide a resolution enhanced spectrum of available output channels at an output plane, said spectrum being shiftable in said output plane by operation of said optical deflector assembly. - View Dependent Claims (10, 11, 12, 13)
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14. A method for increasing wavelength channels available for output from a tunable optical filter tunable across substantially the entire EDFA passband comprising:
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acousto-optically deflecting light input; controlling deflection angle of said light input based on desired wavelength channel output; and diffracting the deflected light providing a resolution enhanced spectrum of available wavelength output channels at an output plane, said spectrum of output channels being shiftable in said output plane by control of said deflection angle. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification