Optical interface for hybrid circuit

• US 5,390,271 A
• Filed: 05/03/1993
• Issued: 02/14/1995
• Est. Priority Date: 05/03/1993
• Status: Expired due to Fees

• Current Assignee: Litton Systems Incorporated (Northrop Grumman Corporation)
• Original Assignee: Litton Systems Incorporated (Northrop Grumman Corporation)
• Inventors: Priest, John F.
• Primary Examiner(s): FONT, FRANK G
• Application Number:
  US08/055,316
• Time in Patent Office: 652 Days
• Field of Search: 385/14, 385/31, 385/33, 385/34, 385/35, 385/36, 385/39, 385/47, 385/48, 385/51, 385/88, 385/92, 385/93, 385/94
• US Class Current: 385/92
• CPC Class Codes: G02B 6/4204 the coupling comprising intermediate optical elements, e.g. lenses, holograms encapsulated active devices H01S5/02208, H01L33/52
• CPC Class Codes: G02B 6/4212 the intermediate optical element being a coupling medium interposed therebetween, e.g. epoxy resin, refractive index matching material, index grease, matching liquid or gel
• CPC Class Codes: G02B 6/4214 the intermediate optical element having redirecting reflective means, e.g. mirrors, prisms for deflecting the radiation from horizontal to down- or upward direction toward a device G02B6/4246 takes precedence

Abstract

Apparatus is provided for coupling the optical energy conducted through an optical fiber to an electro-optic hybrid element, such as a photodetector, that is positioned within a hybrid casing. The outer jacket of the fiber is stripped, cleaved to 45 degrees and silvered or coated with a dielectric to form a mirror for directing the optical energy through the side of the cladding. A window, transparent to a predetermined bandwidth of the optical energy, is provided in the lid of the case overlying the electro-optic element. The mirrored end of the fiber is positioned above the window and the element while the fiber is fixed to the top of the lid of the casing. The arrangement requires no ferrule and permits bakeout and testing of the hybrid package prior to engagement of the optical fiber.

Claims

1. Apparatus for coupling the optical energy conducted through an optical fiber surrounded by a fiber jacket to an electro-optic element positioned within a case having a substantially-planar lid comprising, in combination:

a) said lid including a defined region overlying said element characterized by transparency to a predetermined bandwidth of said optical energy;

b) the terminal end of said fiber including a planar surface of reflective character for directing said optical energy in a direction substantially orthogonal to the direction of propagation of optical energy within said fiber; and

c) means for positioning said terminal end of said fiber adjacent said lid so that said predetermined bandwidth of said optical energy is directed through said defined region and at said element.

2. Apparatus as defined in claim 1 wherein said defined region comprises a window characterized by a predetermined bandwidth.

3. Apparatus as defined in claim 2 wherein said window is planar.

4. Apparatus as defined in claim 2 wherein said window comprises an optical lens.

5. Apparatus as defined in claim 1 further characterized in that:

a) said planar surface is formed at the terminal end of said fiber; and

b) said planar surface is inclined at an angle of 45 degrees with respect to the optical axis of said fiber.

6. Apparatus as defined in claim 5 wherein the region between said planar surface and said defined region is encapsulated in optical resin.

7. Apparatus as defined in claim 1 wherein said planar surface is further characterized in that:

a) said surface is formed in a prismatic element; and

b) said element is attached to the terminal end of said fiber.

8. Apparatus as defined in claim 7 wherein the bottom of said prismatic element is fixed to said defined region by means of optical resin.

9. Apparatus as defined in claim 8 wherein said optical resin is an index of refraction matching resin.

10. Apparatus for coupling the optical energy conducted through an optical fiber surrounded by a fiber jacket to an electro-optic element positioned within a case having a substantially-planar lid comprising, in combination:

a) said lid including an internal defined region overlying said element characterized by transparency to a predetermined bandwidth of said optical energy;

b) means associated with the terminal end of said fiber for directing said optical energy in a direction substantially orthogonal to the direction of propagation of optical energy within said fiber; and

c) a straight channel extending substantially from an edge of said lid to said internal defined region, said straight channel having a concave upper surface for positioning the terminal end of said fiber adjacent said lid whereby said optical energy is directed through said defined region and at said element.

11. Apparatus as defined in claim 10 wherein said channel is integral with said lid.