High speed electro-optical signal translator

• US 5,993,074 A
• Filed: 06/20/1997
• Issued: 11/30/1999
• Est. Priority Date: 12/06/1991
• Status: Expired due to Fees

• Current Assignee: Molex Fiber Optics Incorporated
• Original Assignee: Molex Fiber Optics Incorporated
• Inventors: Schmidt, Melvin C., Kaufman, R. Gilbert, Kwasegrock, John G., Ressl, Michael G., Chambers, Frank A.
• Primary Examiner(s): Ullah, Akm E.
• Application Number:
  US08/912,316
• Time in Patent Office: 893 Days
• Field of Search: 385/90-93, 385/80, 385/81, 385/84, 385/88, 385/14, 385/49, 359/152, 359/153, 359/159, 359/173, 359/176, 357/19, 357/30
• US Class Current: 385/90
• CPC Class Codes: G02B 6/4201 Packages, e.g. shape, construction, internal or external details
• CPC Class Codes: G02B 6/4207 with optical elements reducing the sensitivity to optical feedback anti-reflection devices specially adapted for lasers, see H01S3/0064
• CPC Class Codes: G02B 6/4216 incorporating polarisation-maintaining fibres polarisation-maintaining fibres per se G02B6/105
• CPC Class Codes: G02B 6/4221 involving a visual detection of the position of the elements, e.g. by using a microscope or a camera
• CPC Class Codes: G02B 6/4224 using visual alignment markings, e.g. index methods
• CPC Class Codes: G02B 6/4226 Positioning means for moving the elements into alignment, e.g. alignment screws, deformation of the mount
• CPC Class Codes: G02B 6/424 Mounting of the optical light guide
• CPC Class Codes: G02B 6/4243 Mounting of the optical light guide into a groove mounting optical light guides into a groove in general G02B6/3636
• CPC Class Codes: G02B 6/4245 Mounting of the opto-electronic elements
• CPC Class Codes: G02B 6/4266 Thermal aspects, temperature control or temperature monitoring thermal aspect of electrical circuits H05K7/20, H05K5/0213, temperature control in general G05D23/19
• CPC Class Codes: G02B 6/4286 Optical modules with optical power monitoring

Abstract

An electro-optical signal translator, signal translator design features, methods of fabrication, alignment techniques and alignment apparatus that utilize, with the exception of output optical fiber to transmitter module coupling, passive assembly techniques that are compatible with assembly line operations to produce high performance electro-optical signal translators.

Claims

1. An electro-optical translator that serves as an interface between electrical and optical signals, comprising:

a translator component mounting substrate having a defined optical axis

at least one translator component having a defined optical axis that is mounted on an upper surface of said substrate;

an optical fiber mounted on said upper surface of said substrate;

first means for aligning said optical fiber substantially parallel with said optical axis of said substrate;

at least one second means for aligning said at least one component on said upper surface of said substrate that has a fixed relationship with respect to said defined optical axis of said substrate; and

at least one third means for aligning said at least one component on a lower surface of said at least one component that has a fixed relationship with respect to said defined optical axis of said at least one component and a fixed relationship with respect to said second at least one means for aligning.

2. The translator as set forth in claim 1, wherein said first means for aligning comprises a first groove for receiving said optical fiber that extends along said upper surface of said upper surface of said substrate.

3. The translator as set forth in claim 2, wherein said first groove is an anisotropically etched groove in said upper surface of said substrate, and said defined optical axis of said substrate is defined by said first groove.

4. The translator as set forth in claim 3, wherein said at least one second means for aligning comprises a substrate alignment mark that is in alignment with said first groove.

5. The translator as set forth in claim 1, wherein said defined optical axis is defined by an optical device rib that extends along said lower surface of said at least one component.

6. The translator as set forth in claim 5, wherein said third means for aligning comprises a component alignment mark that is in alignment with said optical device rib.

7. The translator as set forth in claim 1, wherein said at least one component comprises a photodetector element with an input having an optical axis substantially parallel to said upper surface of said substrate a predetermined distance above said upper surface, and said first groove has a first groove depth that maintains an optical axis of said optical fiber less that said predetermined distance of said optical axis of said photodetector element from said upper surface.

8. The translator as set forth in claim 3, wherein said at least one component comprises at least a modulator element having a modulator input and a laser element having a first laser output that are butt coupled together on said substrate, and further comprising a second groove extending along said upper surface of said substrate under said modulator input and said first laser output to prevent coupling of phase-mismatched light that is reflected off of the upper surface of said substrate.

9. The translator as set forth in claim 8, wherein said at least one component further comprises a photodetector element with a photodetector input butt coupled to said laser element and said laser element has a second laser output, and further comprising a third groove extending along said upper surface of said substrate under said photodetector input and said second laser output to prevent coupling of phase-mismatched light that is reflected off of the upper surface of said substrate.

10. The translator as set forth in claim 1, wherein said predetermined relationship between said first means for aligning and said second means for aligning comprises and in-line relationship.

11. The translator as set forth in claim 1, wherein said predetermined relationship between said first means for aligning and said second means for aligning comprises a skewed relationship.

18. The translator of claim 1 further comprising an optical fiber holder, said holder comprising:

a substantially planar manipulator engaging surface, said manipulator engaging surface being substantially parallel to the upper surface of said mounting substrate;

a planar side surface substantially perpendicular to said manipulator engaging surface; and

a fiber engaging surface adjacent said optical fiber, said fiber engaging surface having a width less than the width of said manipulator engaging surface.

19. The translator of claim 18 wherein said optical fiber holder further comprises a longitudinal groove in said fiber engaging surface, said groove being adjacent said optical fiber.

12. For an electro-optical signal translator that serves as an interface between electrical and optical signals, a method of attaching an optic fiber to a translator component mounting substrate, comprising the steps of:

attaching a planar surface of an optical fiber holder to a 20 manipulator;

attaching said optical fiber to a groove that runs substantially parallel to said planar surface along an elevated pedestal region of said optical fiber holder;

placing said optical fiber in a groove that runs along an upper surface of said mounting substrate with said manipulator; and

attaching said optical fiber and optical fiber holder to said groove along said mounting substrate surface.

13. For an electro-optical signal translator that serves as an interface between electrical and optical signals, a method of aligning the optical polarization of an optic fiber to be attached to a translator component mounting substrate, comprising the steps of:

rotating said optical fiber to have a predetermined angle of polarization relative to a substantially planar surface of an optical fiber holder;

attaching said optical fiber in a groove of said optical fiber holder that runs substantially parallel to said planar surface of said optical fiber holder; and

attaching said optical fiber to an upper surface of said mounting substrate with said planar surface of said optical fiber holder substantially parallel to said upper surface of said mounting substrate to align the polarization of said optical fiber to said predetermined angle of polarization relative to said upper surface of said mounting substrate.

14. For an electro-optical signal translator that serves as an interface between electrical and optical signals, a method of attaching an optic fiber to a translator component mounting substrate, comprising the steps of:

mounting a photodetector element with an input having an optical axis substantially parallel to an upper surface of said substrate a predetermined distance above said upper surface;

attaching said optic fiber in a groove running substantially parallel to said optical axis of said photodetector axis along said upper surface of said substrate with a groove depth that maintains an optical axis of said fiber less than said predetermined distance of said optical axis of said photodetector element from said upper surface.

15. For an electro-optical signal translator that serves as an interface between electrical and optical signals, an optical fiber holder for attaching an optic fiber to a translator component mounting substrate, comprising:

a substantially planar upper surface;

at least one substantially planar side surface that is substantially perpendicular to said upper surface;

a pedestal region extending away from said upper surface that has a pedestal surface parallel to said upper surface; and

a fiber-holding groove that runs along said pedestal surface substantially parallel to said side surface.

16. The optical fiber holder of claim 15 further comprising a lower surface adapted for attachment to an optical fiber in a substantially parallel relationship with said upper surface, said lower surface having a width less than the width of said upper surface.

17. The optical fiber holder of claim 16 wherein said lower surface comprises a longitudinal groove.

20. An electro-optical translator comprising:

a translator component mounting substrate having a defined optical axis and a substrate alignment mark on the upper surface of said substrate, said alignment mark having a fixed relationship with said optical axis; and

a translator component mounted on the upper surface of said substrate, said component having a defined optical axis and a component alignment mark on the lower surface of said component, said alignment mark having a fixed relationship with said optical axis,

wherein said component alignment mark is registered with said substrate alignment mark to effect the alignment of said optical axes.