Generating electronic carrier signals in the optical domain
First Claim
1. An optical system, comprising:
- a dual wavelength optical waveguide laser comprising a first optical waveguide containing an optical gain medium, the waveguide including a first grating section in which a first optical waveguide grating device is provided, the first optical waveguide grating device having a periodic refractive index variation which gives the first optical waveguide grating a spectral profile having two passbands located within a stopband, the first grating section being birefringent, the first optical waveguide grating device defining at least one distributed optical waveguide laser cavity, the first optical waveguide being optically coupled at one end to a second optical waveguide including a second grating section in which a second, mode-selecting optical waveguide grating device is provided, the first optical waveguide grating device, in combination with the first birefringent grating section, giving rise to two potential lasing modes of a first polarization state and two potential lasing modes of a second polarization state orthogonal to the first polarization state, each potential lasing mode being of a different wavelength, the second optical waveguide grating device selecting two orthogonal modes for oscillation; and
a pump laser, operable to generate a pump optical signal, in optical communication with the first optical waveguide.
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Accused Products
Abstract
A dual wavelength optical fiber distributed feedback laser comprises a pump laser coupled to a birefringent fiber in which a first grating device (two co-located single phase-shift fiber Bragg gratings (FBGs)) is provided. The grating device gives the laser two potential lasing modes in each of two orthogonal polarization states. A polarization mode coupling FBG selects two orthogonally polarized modes on which the laser oscillates. In a photonic data carrying signal source, the laser is coupled to a polarization dependent, optical modulator operable to apply a modulation, at a data signal frequency, to one polarization mode of the laser output. In an optical waveguide based electronic signal transmission system the modulated and un-modulated polarization modes output from the source are transmitted across a fiber transmission line to a polarizing optical fiber in which the two modes heterodyne to generate an electronic carrier signal in the optical domain.
9 Citations
18 Claims
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1. An optical system, comprising:
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a dual wavelength optical waveguide laser comprising a first optical waveguide containing an optical gain medium, the waveguide including a first grating section in which a first optical waveguide grating device is provided, the first optical waveguide grating device having a periodic refractive index variation which gives the first optical waveguide grating a spectral profile having two passbands located within a stopband, the first grating section being birefringent, the first optical waveguide grating device defining at least one distributed optical waveguide laser cavity, the first optical waveguide being optically coupled at one end to a second optical waveguide including a second grating section in which a second, mode-selecting optical waveguide grating device is provided, the first optical waveguide grating device, in combination with the first birefringent grating section, giving rise to two potential lasing modes of a first polarization state and two potential lasing modes of a second polarization state orthogonal to the first polarization state, each potential lasing mode being of a different wavelength, the second optical waveguide grating device selecting two orthogonal modes for oscillation; and
a pump laser, operable to generate a pump optical signal, in optical communication with the first optical waveguide. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A dual wavelength optical waveguide laser, comprising:
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a first optical waveguide comprising an optical gain medium and a first grating section, the first grating section comprising a first optical waveguide grating device having a periodic refractive index variation giving the first optical waveguide grating a spectral profile having two passbands located within a stopband, the first grating section being birefringent and the first optical waveguide grating device further comprising at least one distributed laser cavity the first grating device thereby defining two potential oscillation wavelengths of a first polarization state and two potential oscillation wavelengths of a second polarization state orthogonal to the first polarization state, each potential oscillation wavelength being different; and
a second optical waveguide optically coupled to one end of the first optical waveguide, the second optical waveguide comprising a second grating section, a second, mode-selecting optical waveguide grating device being provided in the second grating section;
wherein the second optical waveguide grating device selects a pair of orthogonally polarized potential oscillation wavelengths for laser oscillation. - View Dependent Claims (15, 16, 17, 18)
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Specification