Apparatus for transforming the aspect ratio of an optical input field based on stacked waveguides

• US 8,442,363 B2
• Filed: 05/25/2010
• Issued: 05/14/2013
• Est. Priority Date: 06/05/2009
• Status: Active Grant

• Current Assignee: Diabesen Technologies (Beijing) Co. Ltd.
• Original Assignee: C8 MediSensors, Inc.
• Inventors: Hallstein, Sascha, Ice, Donald A.
• Primary Examiner(s): Doan, Jennifer
• Application Number:
  US12/786,751
• Publication Number:
  US 20100310209A1
• Time in Patent Office: 1,085 Days
• Field of Search: 385/15, 385/27, 385/31, 385/32
• US Class Current: 385/27
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0205 Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows
• CPC Class Codes: G01J 3/0229 using masks, aperture plates, spatial light modulators or spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 3/024 using means for illuminating a slit efficiently (e.g. entrance slit of a spectrometer or entrance face of fiber)
• CPC Class Codes: G01J 3/04 Slit arrangements slit adjustment
• CPC Class Codes: G02B 27/0994 Fibers, light pipes optical fibers per se G02B6/02
• CPC Class Codes: G02B 6/0076 Stacked arrangements of multiple light guides of the same or different cross-sectional area
• CPC Class Codes: G02B 6/10 of the optical waveguide type G02B6/02, G02B6/24 take precedence; devices or arrangements for the control of light by electric, magnetic, electro-magnetic or acoustic means G02F1/00; transferring the modulation of modulated light G02F2/00; optical logic elements G02F3/00; optical analogue/digital converters G02F7/00
• CPC Class Codes: G02B 6/26 Optical coupling means G02B6/36, G02B6/42 take precedence

Abstract

An apparatus consisting of stacked slab waveguides whose outputs are vertically staggered is disclosed. At the input to the stacked waveguides, the entrances to each slab lie in approximately the same vertical plane. A spot which is imaged onto the input will be transformed approximately to a set of staggered rectangles at the output, without substantial loss in brightness, which staggered rectangles can serve as a convenient input to a spectroscopic apparatus. A slit mask can be added to spatially filter the outputs so as to present the desired transverse width in the plane of the spectroscopic apparatus parallel to its dispersion.

Claims

1. An apparatus for converting a shape of an optical input to a differently shaped optical output, comprising:

at least two stacked slab waveguides wherein a location light is input along a portion of one side of each of the waveguides is distinct from a location light is output from one side of each of the waveguides;

wherein the volume of any of the stacked slab waveguides is the volume traversed by translating a quadrilateral in a direction perpendicular to the plane of the quadrilateral;

wherein there is a geometrical difference between each waveguide such that the location light is output from each of the waveguides is displaced in at least two directions with respect to each other, or the location light is input to each of the waveguides is displaced in at least two directions with respect to each other;

wherein an aggregate area of the locations light is input to the waveguides corresponds approximately to the shape of the optical input; and

wherein an aggregate area of the locations light is output from the waveguides corresponds approximately to a desired shape of optical output, wherein the desired shape of the optical output is different from the shape of the optical input.

2. The apparatus of claim 1, wherein the quadrilateral is a parallelogram.

3. The apparatus of claim 1, wherein two of the angles between respective adjacent edges in the plane of the quadrilateral are substantially 45°

.

4. The apparatus of claim 3, wherein the at least two slab waveguides are rhomboids, each having a different long dimension.

5. The apparatus of claim 1, where at least one side perpendicular to the plane of the quadrilateral is a mirror.

6. The apparatus of claim 5, wherein at least some light propagating in the waveguide undergoes total internal reflection at the mirror.

7. The apparatus of claim 1, wherein the locations light is input and output of the waveguides are antireflection coated.

8. The apparatus of claim 7, wherein the coating of the locations light is input and output of the waveguides extends substantially along an entire length of those sides and acts as a waveguide cladding in areas distinct from the locations light is input and output.

9. The apparatus of claim 8, wherein the coating has a thickness substantially of ¼

wavelength plus an integral number of half wavelengths of the input light in an index of the coating material.

10. The apparatus of claim 1, wherein a guiding material of the waveguides is glass with an index greater than 1.80.

11. The apparatus of claim 1, wherein an aggregate area of the locations light is output from the waveguides is further restricted by a mask.

12. The apparatus of claim 1, wherein the outputs from the waveguide are curved so as to compensate for a curvature of constant wavelength contours in a spectrometer to which the apparatus inputs light.

13. The apparatus of claim 1, wherein one or more sides of the slab waveguides are curved, wherein a form of the curvatures differs between waveguides so as to produce a displacement either in the location light is output from each of the waveguides with respect to each other, or in the location light is input from each of the waveguides with respect to each other.

14. The apparatus of claim 1, wherein the shape of the optical input is nominally circular, and the desired shape of the optical output is a staggered set of nominally rectangular outputs from the waveguides.

15. The apparatus of claim 1, wherein the ratio of the aspect ratio of the optical input to the aspect ratio of the optical output is less than 0.5.

16. The apparatus of claim 1, wherein the ratio of the aspect ratio of the optical input to the aspect ratio of the optical output is greater than 2.0.