US 12,321,014 B2Granted

Coupling devices and methods, wavelength locking systems and methods, and phase unwrapping systems and methods

AssigneeApple Inc.

InventorsMohamed Mahmoud, Yi-Kuei Wu, Lucia Gan

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Abstract

Configurations for an optical device used for light splitting and wavelength locking are disclosed. The optical device may be a two by three coupler with a first waveguide coupled to a second waveguide, and a third waveguide coupled to the second waveguide. The first and third waveguides may receive input light and optically couple light to the second waveguide. The output signals of the first, second, and third waveguides may have a constant phase difference from one another over a broadband wavelength range, which may allow for phase unwrapping. By phase unwrapping the output signals over an FSR and performing further phase unwrapping over the broadband wavelength range, a continuous signal may be produced and used to sequentially lock each wavelength of light emitted by light sources over the broadband wavelength range.

Claims11

Dependent claims

An optical device, comprising:

a light source configured to generate light;
a splitter for receiving and splitting the light received from the light source into a first light along a first light path and a second light along a second path;
a phase shifter positioned to receive the first split light along the first light path and to phase shift the first split light relative to the second split light;
a two by three coupler comprising:
a first waveguide configured to:
receive the first split light along the first light path;
and
output a first output signal with a first wavelength response and a first phase shift;
a second waveguide optically coupled to the first waveguide and configured to output a second output signal with a second wavelength response and a second phase shift;
and
a third waveguide optically coupled to the second waveguide and configured to:
receive the second split light along the second light path;
and
output a third output signal with a third wavelength response and a third phase shift;
and
a set of photodetectors positioned to receive the first output signal, the second output signal, and the third output signal, wherein:
the first phase shift and the second phase shift are offset by a first phase difference;
the second phase shift and the third phase shift are offset by a second phase difference;
the first phase shift and the third phase shift are offset by a third phase difference;
the first phase difference, the second phase difference, and the third phase difference are constant
the first waveguide, the second waveguide, and the third waveguide have constant widths in a coupling region;
and
the second waveguide is wider than the first waveguide and the third waveguide in the coupling region.

20 more elements

An optical system for monitoring a wavelength of a light source, comprising:

the light source configured to generate light;
a splitter for receiving and splitting the light received from the light source into a first split light along a first light path and a second split light along a second path;
a phase shifter positioned to receive the first split light along the first light path and to phase shift the first split light relative to the second split light;
a two by three coupler comprising a first waveguide, a second waveguide, and a third waveguide, and configured to:
receive the first split light from the phase shifter at the first waveguide along the first light path;
receive the second split light from the splitter at the third waveguide along the second light path;
and
output a first output signal from the first waveguide, a second output signal from the second waveguide, and a third output signal from the third waveguide, each of which has a respective intensity based on a respective interference between the first split light and the second split light;
a set of photodetectors positioned to receive the first output signal, the second output signal, and the third output signal;
and
a controller configured to monitor a wavelength of the light received by the splitter using intensities of the first output signal, the second output signal, and the third output signal, wherein:
the first waveguide, the second waveguide, and the third waveguide have constant widths in a coupling region;
and
the second waveguide is wider than the first waveguide and the third waveguide in the coupling region.

11 more elements

Dependencies are inferred from the claim text.

Facts

Application: 17/827,281Filed 27 May 2022 · us provisional application
Priority: 24 Aug 2021
Published: US 2023/0062578 A12 Mar 2023
Granted: 3 Jun 2025
Term ends: Not estimatedThe source records don’t support an estimate.

Classification13 codes

G02B 6/125
Basic optical elements, e.g. light-guiding paths: bends, branchings or intersections
G02B 6/29301
With wavelength selective means: based on a phased array of light guides
G02B 6/12004
Of the integrated circuit kind: combinations of two or more optical elements
G02B 6/1228
Basic optical elements, e.g. light-guiding paths: tapered waveguides, e.g. integrated spot-size transformers