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US 12,001,054 B2Granted
Wideband grating coupler
AssigneeThe Chinese University of Hong Kong
InventorsXuetong Zhou, Hon Ki Tsang
Life of this patent
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Abstract
An output coupler can be used to couple multiple channels of light from a semiconductor waveguide to an optical fiber for wavelength division multiplexing. To couple light of a wide bandwidth (e.g., equal to or greater than 100 nm), two symmetrical gratings on two sides of a Fabry Perot cavity is used. The two symmetrical gratings are optimized to both reflect light for a Fabry Perot resonator and couple light out of the semiconductor waveguide.
Claims20
A system for optical communication, comprising:
- a waveguide having a semiconductor core, wherein the semiconductor core is configured to guide light along a first propagation direction;
- and
- a coupler comprising:
- a first grating,
- a second grating, and
- walls forming an optical cavity between the first grating and the second grating, wherein:
- there is no gain medium between the first grating and the second grating,
- the coupler is configured to couple light out of the waveguide along a second propagation direction, and
- the second propagation direction is not parallel to the first propagation direction.
6 more elements
A method for coupling light out of an optical waveguide, the method comprising:
- receiving light from a waveguide, wherein the light propagates in a first propagation direction in the waveguide;
- reflecting the light, using a first grating, so that the light passes through an optical cavity wherein light passing through the optical cavity does not pass through a gain medium;
- reflecting the light, using a second grating, after the light passes through the optical cavity;
- and
- directing the light, using the first grating or the second grating, in a second propagation direction, wherein the second propagation direction is not parallel with the first propagation direction.
2 more elements
An apparatus, comprising:
- a first grating,
- a second grating, and
- walls forming an optical cavity between the first grating and the second grating, wherein:
- there is no gain medium between the first grating and the second grating;
- the first grating and the second grating are configured to diffract light, propagating parallel to a first propagation direction, to propagate in a second propagation direction and reflect light in a direction parallel to the first propagation direction;
- the second propagation direction is not parallel to the first propagation direction;
- diffracting light uses a first order diffraction;
- and
- reflecting light uses a second order reflection.
6 more elements
Dependencies are inferred from the claim text.