Grating assisted acousto-optic tunable filter and method
AssigneeThe United States of America as represented by the Secretary of Commerce
InventorEung Gi Paek
Life of this patent
Estimating the term…
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).
Claims20
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.
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:
- 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.
A method for increasing wavelength channels available for output from a tunable optical filter tunable across substantially the entire EDFA passband comprising:
- 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.
Dependencies are inferred from the claim text.