Bandwidth-adjusted wavelength demultiplexer
AssigneeCorning Incorporated
InventorDenis M. Trouchet
Life of this patent
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Abstract
A tradeoff between crosstalk and channel bandwidth in dense wavelength demultiplexers is achieved by varying mode fields of input and output waveguides. Funnels are formed between inner and outer ends of the input and output waveguides to increase mode field radii, which results in decreased crosstalk attenuation but larger bandwidth channels.
Claims25
A wavelength multiplexer/demultiplexer for routing optical signals within different wavelength channels and having a requirement for a minimum amount of crosstalk attenuation between adjacent channels of at least 20 decibels comprising:
- a first conductor that conveys a plurality of optical signals within the different wavelength channels along a length that extends between outer and inner ends;
- a series of second conductors that separately convey the optical signals within the different wavelength channels along respective lengths that extend between inner and outer ends;
- a dispersing and focusing optic that disperses the optical signals within the different wavelength channels emitted from said inner end of the first conductor and separately focuses the respective optical signals within the different wavelength channels on said inner ends of the series of second conductors;
- couplings coefficient being defined between said first conductor and each of said second conductors expressible as a loss in decibels over a domain of wavelengths centered at the respective channel wavelengths;
- each of said different wavelength channels having a channel bandwidth defined by a range of wavelengths at which the decibel loss is varied by less than a predetermined amount;
- funnels formed between said inner and outer ends of the second conductors and having a first width corresponding to a width of said second conductors between said funnels and said outer ends of the second conductors and a second width corresponding to a width at said inner ends of the second conductors;
- and
- said second width being adjusted with respect to said first width to achieve said minimum amount of crosstalk attenuation at a maximized amount of channel bandwidth.
An optical routing device referenced in a direction of light travel for demultiplexing signals of different wavelength channels and having a requirement for a minimum amount of crosstalk attenuation between adjacent channels comprising:
- an input waveguide exhibiting an input waveguide mode field;
- a series of output waveguides each exhibiting an output waveguide mode field;
- a reflective diffraction grating exhibiting a series of dispersed fields that substantially image the input waveguide mode field on each of said output waveguides whereby multiple channels conveyed by said input waveguide are separately conveyed by said output waveguides;
- and
- funnels formed in said input and output waveguides similarly sizing the input and output mode fields to produce said minimum amount of crosstalk attenuation while maximizing the bandwidths of the channels conveyed by the input and output waveguides with a minimum amount of coupling losses.
A method of optimizing channel bandwidth at a required minimum amount of crosstalk attenuation between adjacent channels in a multiplexing/demultiplexing optical device comprising the steps of:
- coupling an input waveguide to a series of output waveguides with a dispersive optic producing a series of dispersed fields that substantially image a mode field of the input waveguide on each of said output waveguides in a demultiplexing mode and that substantially image respective mode fields of the output waveguides on the input waveguide in a multiplexing mode;
- forming funnels in the input and output waveguides to adjust sizes of the input and output waveguide mode fields;
- and
- increasing the size of the input and output waveguide mode fields for reducing excess crosstalk attenuation until the crosstalk attenuation reaches the required minimum amount.
Dependencies are inferred from the claim text.