Planar waveguide reflective diffraction grating
First Claim
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1. A reflective diffraction grating device on a planar waveguide platform for use in demultiplexing an optical signal, comprising:
- an input port for launching a beam of light comprising a plurality of wavelength channels, defined by an average wavelength, at a small diffraction grating incident angle;
a reflective diffraction grating for dispersing the wavelength channels at various angles according to wavelength, the reflective diffraction grating having a plurality of substantially triangular steps, each step comprising a reflective wall defined by a facet length, and a sidewall defined by a sidewall length; and
a plurality of output ports positioned to capture the wavelength channels;
wherein an aspect ratio, defined by the facet length divided by the sidewall length, is greater than 3.
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Abstract
The invention relates to a planar waveguide reflective diffraction grating for use in an optical device, such as a wavelength division multiplexer, providing an increased bandwidth over conventional planar waveguide reflection diffraction gratings while eliminating the polarization dependent loss (PDL) typically associated therewith. Accordingly, a low order (<3), high aspect ratio (>10) grating is provided with a very short side wall (less than the wavelength of the optical signal) for use with incident angles of less than 15°.
59 Citations
33 Claims
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1. A reflective diffraction grating device on a planar waveguide platform for use in demultiplexing an optical signal, comprising:
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an input port for launching a beam of light comprising a plurality of wavelength channels, defined by an average wavelength, at a small diffraction grating incident angle; a reflective diffraction grating for dispersing the wavelength channels at various angles according to wavelength, the reflective diffraction grating having a plurality of substantially triangular steps, each step comprising a reflective wall defined by a facet length, and a sidewall defined by a sidewall length; and a plurality of output ports positioned to capture the wavelength channels; wherein an aspect ratio, defined by the facet length divided by the sidewall length, is greater than 3. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A reflective diffraction grating device on a planar waveguide platform for use in multiplexing or demultiplexing optical channels defined by an average wavelength, comprising:
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a reflective diffraction grating including a plurality of substantially triangular steps, each step comprising; a reflective wall defined by a facet length; and a non-reflecting sidewall defined by a sidewall length; an input port for launching a beam of light comprising the optical channels at the diffraction grating at a small incident angle; a first output port for outputting one of the optical channels; and a second output port for outputting another of the optical channels; wherein the facet length and the incident angle are selected to ensure that the grating provides diffraction in an order with an absolute value of 7 or less. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A reflective diffraction grating device on a planar waveguide platform for use in demultiplexing an optical signal, comprising:
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an input port for launching a beam of light comprising a plurality of wavelength channels, defined by an average wavelength, at a small diffraction grating incident angle; a reflective diffraction grating for dispersing the wavelength channels at various angles according to wavelength, the reflective diffraction grating having a plurality of steps defining substantially triangular grooves, each step comprising a reflective wall defined by a facet length, and a sidewall defined by a sidewall length; and a plurality of output ports positioned to capture the wavelength channels; wherein the sidewall length is less than or equal to twice the average wavelength. - View Dependent Claims (25, 26, 27, 28, 29, 30)
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31. A reflective diffraction grating device on a planar waveguide platform for use in demultiplexing an optical signal, comprising:
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an input port for launching a beam of light comprising a plurality of wavelength channels, defined by an average wavelength, at a diffraction grating incident angle; a reflective diffraction grating for dispersing the wavelength channels at various angles according to wavelength, the reflective diffraction grating having a plurality of steps defining substantially triangular grooves, each step comprising a reflective wall defined by a facet length, and a sidewall defined by a sidewall length; and a plurality of output ports positioned to capture the wavelength channels;
wherein the sidewall length is less than or equal to twice the average wavelength; andwherein the facet length is greater than 5 μ
m. - View Dependent Claims (32, 33)
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Specification