Method and apparatus for wavelength-selective switches and modulators
First Claim
1. An optical apparatus for receiving a multi-wave input optical signal comprising:
- a first planar lightwave circuit (PLC) including;
an input/output waveguide, a first waveguide array having a first waveguide coupler, a second waveguide coupler and at least two waveguides optically connecting the first and second couplers, wherein the first coupler is directly coupled to the input/output wave guide, and wherein said array exhibits a free-spectral range equal to the channel separation of the input optical signal, the first waveguide array introducing a first dispersion into the input optical signal, a second waveguide array including an input waveguide coupler, wherein the input coupler is directly coupled to the second coupler of the first waveguide array, and wherein the second waveguide array has a plurality of waveguides terminating at an edge facet of the PLC and exhibits a free-spectral range equal to all of the channels of the input optical signal and produces a second dispersion into the input optical signal which adds to the first dispersion;
a lens adjacent to the PLC; and
an optical receiving unit adjacent to the lens;
wherein the edge facet of the PLC and the optical receiving unit are respectively positioned at a front focal plane and a back focal plane of the lens such that an input optical signal is propagated through the PLC to generate a phased array output at the edge facet of the PLC, the phased array output is spatially Fourier transformed by the lens to generate a spectrally resolved image having a discrete or somewhat discrete light spot for each channel or band of channels of the input optical signal which is coupled to the optical receiving unit.
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Abstract
An apparatus and method are provided for manipulating light beams propagated through an optical apparatus that includes a planar lightwave circuit (PLC) and free-space optics unit. A multi-wave optical signal coupled to the PLC is propagated through a first and second waveguide array to generate a phased array output at an edge facet of the PLC. The phased array output at the edge facet is spatially Fourier transformed by the lens to generate a spectrally resolved image having a discrete light spot for each channel of the input optical signal, which is coupled to a pixelated optical receiving unit. When the optical receiving unit is a reflector, one or more of the discrete light spot are reflected to a desired waveguide array of a PLC to produce a desired output. When the optical receiving unit is a pixelated transmissive modulator, one or more of the discrete light spot are modulated as they pass through the modulator.
16 Citations
9 Claims
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1. An optical apparatus for receiving a multi-wave input optical signal comprising:
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a first planar lightwave circuit (PLC) including;
an input/output waveguide, a first waveguide array having a first waveguide coupler, a second waveguide coupler and at least two waveguides optically connecting the first and second couplers, wherein the first coupler is directly coupled to the input/output wave guide, and wherein said array exhibits a free-spectral range equal to the channel separation of the input optical signal, the first waveguide array introducing a first dispersion into the input optical signal, a second waveguide array including an input waveguide coupler, wherein the input coupler is directly coupled to the second coupler of the first waveguide array, and wherein the second waveguide array has a plurality of waveguides terminating at an edge facet of the PLC and exhibits a free-spectral range equal to all of the channels of the input optical signal and produces a second dispersion into the input optical signal which adds to the first dispersion;
a lens adjacent to the PLC; and
an optical receiving unit adjacent to the lens;
wherein the edge facet of the PLC and the optical receiving unit are respectively positioned at a front focal plane and a back focal plane of the lens such that an input optical signal is propagated through the PLC to generate a phased array output at the edge facet of the PLC, the phased array output is spatially Fourier transformed by the lens to generate a spectrally resolved image having a discrete or somewhat discrete light spot for each channel or band of channels of the input optical signal which is coupled to the optical receiving unit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for optical switching comprising the steps of:
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receiving a multi-wavelength light signal into an input/output waveguide of a wavelength selective switch;
coupling the light beam into a first waveguide array having a free-spectral range equal to the channel separation of the multi-wavelength light signal wherein said first waveguide array including a first waveguide coupler, a second waveguide coupler and at least two waveguides optically connecting the first coupler to the second coupler and introduces a first dispersion into the multi-wave light signal;
coupling the light beam output directly from the second coupler of the first waveguide array to an input waveguide coupler included in a second waveguide array having a free-spectral range equal to or greater than all of the channels of the multi-wave light signal and that introduces a second dispersion into the multi-wave light signal which periodically cancels the first dispersion, the second waveguide array terminates at an edge facet and generates a phased array output; and
spatially Fourier transforming the phased array output using one or more lenses to generate a spectrally resolved image having a discrete light spot for each channel of the multi-wave light signal.
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Specification