# US 5,710,629 A · Interferometric measuring device forming a spacial interference pattern

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- Number: US 5,710,629 A
- Document ID: US5710629A
- Status: Granted
- Kind: A
- Application number: 08/432,118
- Filed: 1995-05-05
- Granted: 1998-01-20
- Earliest claimed: 1992-12-10
- Assignees: Schneider Electric SA
- Inventors: Antoine Kevorkian; Isabelle Duport-Schanen; Pierre Benech
- Web page: https://patentgrep.com/patent/US5710629A

## CPC

- G02B 6/12004: {Combinations of two or more optical elements}
- G01B 9/02032: {generating a spatial carrier frequency, e.g. by creating lateral or angular offset between reference and object beam (shearing interferometers G01B9/02098)}
- G02B 6/122: Basic optical elements, e.g. light-guiding paths
- G02B 2006/12195: {Tapering}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS

## Abstract

Two input beams (10, 20) of the interferometric measuring device, achieved according to the integrated optics technology, are broadened so as to form two spread flat beams creating an interference pattern (30). Two detectors (14, 15) supply two measuring signals, preferably in phase quadrature, representative of two points of the interference plane.

## Claims

### Claim 1

A fully integrated interferometric measuring device, comprising:
a rigid block including first and second waveguides which form respective first and second optical transmission channels for mutually coherent input signals, said rigid block including broadening means for generating first and second spread flat beams respectively in the first and second channels such that each spread flat beam has substantially flat wavefronts, the wavefronts of the first and second beams intersecting each other along an axis of symmetry and forming a preset angle therebetween, the wavefronts creating a spatial interference pattern comprising fringes along an interference zone which extends perpendicular to the axis of symmetry, said broadening means comprising at least one broadening device provided in the first and second optical transmission channels; and
analyzing means for analyzing said interference fringes, the analyzing means comprising detectors disposed in the interference zone along an output face of the rigid block.

### Claim 2 (depends on 1)

The device of claim 1, wherein said present angle is 1.degree..

### Claim 3 (depends on 1)

The device of claim 1, wherein the at least one beam broadening device comprises at least one planar lens integrated with said rigid block.

### Claim 4 (depends on 1)

The device of claim 1, wherein the at least one beam broadening device comprises at least one taper.

### Claim 5 (depends on 1)

The device of claim 1, wherein the detection means comprises at least one detector having a length corresponding substantially to a half fringe of the interference pattern.

### Claim 6 (depends on 5)

The device of claim 5, wherein the device comprises two detectors spaced apart from each other by a distance equal to 1/4+nl, wherein l is the fringe width and n is an integer.

### Claim 7 (depends on 1)

The device of claim 1, wherein said detection means comprises a detection device supplying at least two electronic signals providing a preset phase difference.

### Claim 8 (depends on 7)

The device of claim 7, wherein said detection device supplies two electronic signals in phase quadrature.

### Claim 9 (depends on 1)

The device of claim 1, wherein said detectors comprise an array of detector elements positioned to detect substantially the entirety of the interference pattern.