Wavelength and bandwidth tunable optical system
First Claim
1. A tunable optical filter device for modifying an optical signal comprising:
- a first optical filter for reflecting at least a band of first predetermined wavelengths of incident light and for transmitting other wavelengths;
a second optical filter optically coupled to the first optical filter and for transmitting at least a band of second predetermined wavelengths of incident light and for reflecting other wavelengths; and
tuning means for tuning at least one of the first optical filter and the second optical filter such that at least part of the band of first predetermined wavelengths overlaps with at least part of the band of second predetermined wavelengths.
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Accused Products
Abstract
A system for modifying an input optical signal by reducing its bandwidth and modifying its central wavelength has an optical circulator with at least three ports and at least two optical filters coupled to consecutive ports of the circulator. The first filter produces a predetermined reflected band off the input optical signal. The second filter produces a predetermined transmission band as a part of the reflected band. Either or both of the optical filters are tunable to shape and trim the input signal in a predetermined manner. A multi-channel and cascade configurations may be formed. The system may serve e.g. as a tunable filter or as an add/drop module in WDM communication networks.
37 Citations
22 Claims
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1. A tunable optical filter device for modifying an optical signal comprising:
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a first optical filter for reflecting at least a band of first predetermined wavelengths of incident light and for transmitting other wavelengths; a second optical filter optically coupled to the first optical filter and for transmitting at least a band of second predetermined wavelengths of incident light and for reflecting other wavelengths; and tuning means for tuning at least one of the first optical filter and the second optical filter such that at least part of the band of first predetermined wavelengths overlaps with at least part of the band of second predetermined wavelengths. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A tunable optical filter device for modifying an optical signal comprising:
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a first optical filter having a predetermined reflection spectrum, for receiving said optical signal and for producing a reflected band within said reflection spectrum, a second optical filter having a predetermined transmission spectrum, said second optical filter being optically coupled to said reflected band of said first optical filter, for producing a transmitted band within said transmission spectrum, and tuning means for tuning at least one of said first optical filter and said second optical filter to cause said reflection spectrum of said first filter to partly overlap in a predetermined manner with the wavelength and bandwidth of said optical signal thus causing said first filter to produce a reflected band, and to cause said transmission spectrum of said second optical filter to overlap with said reflected band in a predetermined manner. - View Dependent Claims (15, 16, 17, 18)
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19. A tunable optical filter device for modifying an optical signal comprising:
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an optical circulator having an input port for receiving an optical signal, a plurality N of second ports and an output port; a first optical filter having a reflection spectrum and coupled to a first of said second ports, for producing a reflected band from said optical signal within said reflection spectrum; a plurality N-1 of consecutive optical filters coupled to said respective second ports of said optical circulator, said consecutive optical filters each having a reflection spectrum, for producing a reflected band within said reflection spectrum, from a reflected band received from a preceding optical filter; and tuning means for tuning at least one of said first optical filter and said consecutive optical filter such as to cause said reflection spectrum of said first filter to partly overlap in a predetermined manner the bandwidth of said optical signal and to cause said reflection spectra of said consecutive optical filters to overlap in a predetermined manner. - View Dependent Claims (20, 21, 22)
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Specification