US 10,768,361 B1Granted

System for monitoring grating formation

AssigneeFacebook Technologies, LLC

InventorsMatthieu Charles Raoul Leibovici, Kavous Jorabchi, Austin Lane

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Abstract

A monitoring system monitors changes in an index of refraction of the grating over a time interval that includes the period of time. The monitoring system includes a light source assembly, a probing assembly, a power meter (e.g., a diffraction and/or a transmittance power meter), and a controller. The light source assembly emits a probe beam. The scanning assembly scans the probe beam over an area of the grating. The power meter measures power of a portion of the probe beam that interacts (e.g., is transmitted by or diffracted from) with the area of the grating. The controller determines changes in grating parameters (may be as a function of time) for the grating being formed based in part on measured power readings over the time interval.

Claims17

Dependent claims

A manufacturing system comprising:

a grating manufacturing system configured to form a grating over a period of time;
a monitoring system configured to monitor changes in an index of refraction of the grating as a function of time over a time interval that includes the period of time, the monitoring system comprising:
a light source assembly configured to emit a probe beam;
a probing assembly configured to scan the probe beam over an area of the grating;
a beam splitter configured to split a reference portion from the probe beam;
a reference power meter configured to measure reference power of the reference portion;
a diffraction power meter configured to measure diffraction power of a diffraction portion of the probe beam that is diffracted in the area of the grating;
a transmittance power meter configured to measure transmittance power of a transmittance portion of the probe beam that is transmitted through the area of the grating;
and
a controller configured to determine changes in the index of refraction as a function of time for the grating being formed based in part on the measured diffraction power, the measured transmittance power, and the measured reference power over the time interval.

7 more elements

A monitoring system comprising:

a light source assembly that is configured to emit a probe beam;
a probing assembly that is configured to scan the probe beam over an area of a grating being formed over a period of time by a grating manufacturing system;
a beam splitter configured to split a reference portion from the probe beam;
a reference power meter configured to measure reference power of the reference portion;
a diffraction power meter configured to measure diffraction power of a diffraction portion of the probe beam that is diffracted in the area of the grating;
a transmittance power meter configured to measure power of a transmittance portion of the probe beam that is transmitted through the area of the grating;
and
a controller configured to determine changes in an index of refraction as a function of time for the grating being formed based in part on measured power readings over a time interval that includes the period of time, the measured power readings including the power measured by the reference power meter, the diffraction power meter, and the transmittance power meter.

5 more elements

Dependencies are inferred from the claim text.