OPTICAL ASSEMBLIES FOR FREE-SPACE OPTICAL PROPAGATION BETWEEN WAVEGUIDE(S) AND/OR FIBER(S)

• US 20070237456A1
• Filed: 05/27/2007
• Published: 10/11/2007
• Est. Priority Date: 09/25/2002
• Status: Active Grant

• Current Assignee: Hoya Corporation USA (Hoya Corporation)
• Original Assignee: Xponent Photonics, Inc. (Hoya Corporation)
• Inventors: Blauvelt, Henry, Vernooy, David, Paslaski, Joel
• Granted Patent: US 7,542,638 B2
• Time in Patent Office: Days
• US Class Current: 385/34
• CPC Class Codes: G02B 6/2746 comprising non-reciprocal devices, e.g. isolators, FRM, circulators, quasi-isolators magneto-optic non-reciprocal devices G02F1/093
• CPC Class Codes: G02B 6/30 for use between fibre and thin-film device
• CPC Class Codes: G02B 6/32 having lens focusing means positioned between opposed fibre ends with lens being an integral part of the single fibre end G02B6/262
• CPC Class Codes: G02B 6/3636 the mechanical coupling means being grooves G02B6/3652 takes precedence
• CPC Class Codes: G02B 6/3652 the additional structures being prepositioning mounting areas, allowing only movement in one dimension, e.g. grooves, trenches or vias in the microbench surface, i.e. self aligning supporting carriers
• CPC Class Codes: G02B 6/3692 with surface micromachining involving etching, e.g. wet or dry etching steps surface micromachining involving subtractive techniques B81C1/00055

Abstract

An optical apparatus comprises segments of a GRIN optical medium mounted on a substrate in at least one groove thereon. The GRIN segments are longitudinally spaced apart from one another on the substrate, and are arranged so that a free-space optical beam received through the distal end face of the first GRIN segment is transmitted through the proximal end face of the first GRIN segment, propagates to the proximal end face of the second GRIN segment, is received through the proximal end face of the second GRIN segment, and is transmitted as a free-space optical beam through the distal end face of the second GRIN segment. The GRIN segments can be derived from a single GRIN optical medium mounted on the substrate.

Claims

1. An optical apparatus comprising:

a substrate with at least one groove; and

first and second segments of a GRIN optical medium secured to the substrate in at least one groove thereon, the first and second GRIN segments being longitudinally spaced apart from one another on the substrate and having respective proximal and distal end faces, the first and second GRIN segments being arranged so that a free-space optical beam received through the distal end face of the first GRIN segment (i) is transmitted through the proximal end face of the first GRIN segment, (ii) propagates to the proximal end face of the second GRIN segment, (iii) is received through the proximal end face of the second GRIN segment, and (iv) is transmitted as a free-space optical beam through the distal end face of the second GRIN segment.

2. The apparatus of claim 1 wherein the first and second GRIN segments are arranged so that a divergent free-space optical beam received through the distal end face of the first GRIN segment (i) is transmitted through the proximal end face of the first GRIN segment, (ii) propagates to the proximal end face of the second GRIN segment, (iii) is received through the proximal end face of the second GRIN segment, and (iv) is transmitted as a convergent free-space optical beam through the distal end face of the second GRIN segment.

3. The apparatus of claim 1 further comprising an optical component mounted on the substrate between the proximal ends of the first and second GRIN segments, the optical component having first and second end faces facing the proximal end faces of the first and second GRIN segments, respectively, so that the optical component is thereby arranged so that an optical beam propagating between the proximal end faces of the of the GRIN segments is transmitted through the first and second end faces of the optical component.

4. The apparatus of claim 3 further comprising:

a first optical fiber mounted in a groove on the substrate so that the optical fiber is optically substantially coaxial with the first GRIN segment; and

a second optical fiber mounted in a groove on the substrate so that the optical fiber is optically substantially coaxial with the second GRIN segment.

5. The apparatus of claim 4 further comprising:

a substantially transparent, non-gaseous embedding medium substantially filling an optical path between the distal end face of the first GRIN segment and a proximal end face of the first optical fiber; and

a substantially transparent, non-gaseous embedding medium substantially filling an optical path between the distal end face of the second GRIN segment and a proximal end face of the second optical fiber.

6. The apparatus of claim 3 further comprising:

a substantially transparent, non-gaseous embedding medium substantially filling an optical path between the first end face of the optical component and the proximal end face of the first GRIN segment; and

a substantially transparent, non-gaseous embedding medium substantially filling an optical path between the second end face of the optical component and the proximal end face of the second GRIN segment.

7. The apparatus of claim 1 wherein the first and second GRIN segments are optically substantially coaxial, the apparatus further comprising an optical component mounted on the substrate between the proximal ends of the first and second GRIN segments, the optical component having first and second end faces facing the proximal end faces of the first and second GRIN segments, respectively, so that the optical component is thereby arranged so that an optical beam propagating between the proximal end faces of the of the GRIN segments is transmitted through the first and second end faces of the optical component, the first and second end faces each being substantially normal to the propagation direction of the optical beam thus transmitted.

8. The apparatus of claim 1 wherein the first and second GRIN segments are substantially parallel to and optically laterally displaced from one another, the apparatus further comprising an optical component mounted on the substrate between the proximal ends of the first and second GRIN segments, the optical component having substantially parallel first and second end faces facing the proximal end faces of the first and second GRIN segments, respectively, so that the optical component is thereby arranged so that an optical beam propagating between the proximal end faces of the of the GRIN segments is transmitted through the first and second end faces of the optical component, the first and second end faces each being non-normal with respect to the propagation direction of the optical beam thus transmitted, refraction at the first and second end faces of the optical component defining the propagation direction through the optical component between the first and second GRIN segments.

9. The apparatus of claim 1 wherein the first and second GRIN segments are non-parallel, the apparatus further comprising an optical component mounted on the substrate between the proximal ends of the first and second GRIN segments, the optical component having first and second end faces facing the proximal end faces of the first and second GRIN segments, respectively, so that the optical component is thereby arranged so that an optical beam propagating between the proximal end faces of the of the GRIN segments is transmitted through the first and second end faces of the optical component, the first or the second end face being non-normal with respect to the propagation direction of the optical beam thus transmitted, refraction at the first or the second end face of the optical component defining the propagation direction through the optical component between the first and second GRIN segments.

10. The apparatus of claim 1 further comprising:

a second substrate having at least one groove, the first substrate and the first and second GRIN segments being mounted on the second substrate with the first and second GRIN segments received in at least one groove on the second substrate;

an optical component positioned between the proximal end faces of the first and second GRIN segments, the optical component having first and second end faces facing the proximal end faces of the first and second GRIN segments, respectively, so that the optical component is thereby arranged so that an optical beam propagating between the proximal end faces of the of the GRIN segments is transmitted through the first and second end faces of the optical component;

a first transmission optical element positioned on the second substrate, the first transmission optical element having a proximal end face facing the distal end face of the first GRIN segment and being arranged so that a divergent optical beam emergent from the proximal end face of the first transmission optical element is received though the distal end face of the first GRIN segment; and

a second transmission optical element positioned on the second substrate, the second transmission optical element having a proximal end face facing the distal end face of the second GRIN segment and being arranged so that a convergent optical beam emergent from the distal end face of the second GRIN segment is received through the proximal end face of the second transmission optical element.

11. The apparatus of claim 10 wherein:

the first transmission optical element comprises a first optical fiber mounted in a groove on the second substrate so that the first optical fiber is optically substantially coaxial with the first GRIN segment; and

the second transmission optical element comprises a second optical fiber mounted in a groove on the second substrate so that the second optical fiber is optically substantially coaxial with the second GRIN segment.

12. The apparatus of claim 10 wherein:

the first transmission optical element comprises a first planar optical waveguide formed on the second substrate so that the first planar optical waveguide is optically substantially coaxial with the first GRIN segment; and

the second transmission optical element comprises a second planar optical waveguide formed on the second substrate so that the second planar optical waveguide is optically substantially coaxial with the second GRIN segment.

13. The apparatus of claim 10 wherein:

the first transmission optical element comprises a planar optical waveguide formed on the second substrate so that the planar optical waveguide is optically substantially coaxial with the first GRIN segment; and

the second transmission optical element comprises an optical fiber mounted in a groove on the second substrate so that the optical fiber is optically substantially coaxial with the second GRIN segment.

14. The apparatus of claim 10 further comprising:

a substantially transparent, non-gaseous embedding medium substantially filling an optical path between the first end face of the optical component and the proximal end face of the first GRIN segment; and

a substantially transparent, non-gaseous embedding medium substantially filling an optical path between the second end face of the optical component and the proximal end face of the second GRIN segment.

15. The apparatus of claim 10 further comprising:

a substantially transparent, non-gaseous embedding medium substantially filling an optical path between the proximal end face of the first transmission optical element and the distal end face of the first GRIN segment; and

a substantially transparent, non-gaseous embedding medium substantially filling an optical path between the proximal end face of the transmission optical element and the distal end face of the second GRIN segment.

16. The apparatus of claim 10 wherein the optical component, the first and second GRIN segments, and proximal portions of the first and second transmission optical elements are encapsulated.

17. The apparatus of claim 10 wherein the optical component is mounted on the first substrate.

18. The apparatus of claim 10 wherein the optical component is mounted on the second substrate.

19. The apparatus of claim 10 wherein the optical component comprises an optical isolator.

20. The apparatus of claim 10 wherein:

the optical component comprises a Faraday rotator and a linear polarizer;

at least one of the transmission optical elements comprises a polarization-selective planar waveguide formed on the second substrate; and

the Faraday rotator, polarizer, and polarization-selective planar waveguide together function as an optical isolator.

21. The apparatus of claim 10 further comprising a laser source optically coupled to the first transmission optical element at a distal portion thereof so that optical output power from the laser source is transmitted into the second transmission optical element through the first transmission optical element, the first GRIN segment, the optical component, and the second GRIN segment.

22. The apparatus of claim 10 further comprising an optical transceiver optically coupled to the first transmission optical element at a distal portion thereof so that optical power is transmitted between the optical transceiver and the second transmission optical element through the first transmission optical element, the first GRIN segment, the optical component, and the second GRIN segment.

23. The apparatus of claim 10 further comprising a photodetector optically coupled to the first transmission optical element at a distal portion thereof so that optical power is transmitted from the second transmission optical element to the photodetector through the second GRIN segment, the optical component, the first GRIN segment, and the first transmission optical element.

24. The apparatus of claim 1 wherein the GRIN optical medium is a GRIN optical fiber.

25. An optical apparatus comprising:

a substrate with at least one groove; and

first and second segments of a GRIN optical medium mounted on the substrate in at least one groove thereon, the first and second GRIN segments begin derived from a single GRIN optical medium mounted on the substrate, the first and second GRIN segments being longitudinally spaced apart from one another on the substrate and having respective proximal and distal end faces, the first and second GRIN segments being thereby arranged so that a free-space optical beam received through the distal end face of the first GRIN segment (i) is transmitted through the proximal end face of the first GRIN segment, (ii) propagates to the proximal end face of the second GRIN segment, (iii) is received through the proximal end face of the second GRIN segment, and (iv) is transmitted as a free-space optical beam through the distal end face of the second GRIN segment.

26. The apparatus of claim 25 wherein the first and second GRIN segments are arranged so that a divergent free-space optical beam received through the distal end face of the first GRIN segment (i) is transmitted through the proximal end face of the first GRIN segment, (ii) propagates to the proximal end face of the second GRIN segment, (iii) is received through the proximal end face of the second GRIN segment, and (iv) is transmitted as a convergent free-space optical beam through the distal end face of the second GRIN segment.

27. A method for transmitting light through an optical apparatus including first and second segments of a GRIN optical medium mounted on a substrate in at least one groove thereon, the first and second GRIN segments being longitudinally spaced apart from one another and having respective proximal and distal end faces, the method comprising:

receiving a free-space optical beam through the distal end face of the first GRIN segment;

transmitting the beam through the proximal end face of the first GRIN segment;

propagating the beam to the proximal end face of the second GRIN segment;

receiving the beam through the proximal end face of the second GRIN segment; and

transmitting the beam as a free-space optical beam through the distal end face of the second GRIN segment.

28. The method of claim 27 wherein the first and second GRIN segments are arranged so that a divergent free-space optical beam received through the distal end face of the first GRIN segment (i) is transmitted through the proximal end face of the first GRIN segment, (ii) propagates to the proximal end face of the second GRIN segment, (iii) is received through the proximal end face of the second GRIN segment, and (iv) is transmitted as a convergent free-space optical beam through the distal end face of the second GRIN segment.