Optical module and method for assembling the same

• US 6,766,076 B2
• Filed: 03/04/2002
• Issued: 07/20/2004
• Est. Priority Date: 03/15/2001
• Status: Expired due to Fees

• Current Assignee: Nippon Sheet Glass Company Limited (Nippon Telegraph and Telephone Corporation)
• Original Assignee: Nippon Sheet Glass Company Limited (Nippon Telegraph and Telephone Corporation)
• Inventors: Sekiguchi, Yukinari, Kobayashi, Fumitoshi, Hikichi, Naoko, Nakama, Kenichi
• Primary Examiner(s): Ullah, Akm Enayet
• Assistant Examiner(s): CONNELLY, MICHELLE R
• Application Number:
  US10/091,158
• Publication Number:
  US 20020131700A1
• Time in Patent Office: 869 Days
• Field of Search: 385/31, 385/33-35, 385/52, 385/88-94, 385/119, 385/139
• US Class Current: 385/33
• 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 6/322 and having centering means being part of the lens for the self-positioning of the lightguide at the focal point, e.g. holes, wells, indents, nibs
• CPC Class Codes: G02B 6/3644 the coupling means being through-holes or wall apertures
• CPC Class Codes: G02B 6/3672 with fibres arranged in a regular matrix array
• CPC Class Codes: G02B 6/3834 Means for centering or aligning the light guide within the ferrule

Abstract

An optical module is provided in which any conjugate ratio in an optical axis direction may be easily realized, the time duration for alignment may be shortened by using a passive alignment technique, and a large degree of may be obtained for any optical design. The optical module comprises a planar microlens array, a transparent substrate for adjusting a conjugate ratio of the optical module, and a guide substrate for optical fibers. The planar microlens array consists of a planar transparent substrate, in one surface thereof a plurality of circular microlenses are formed and arrayed. The transparent substrate includes a plurality of micro fitting recesses formed and arrayed in one surface thereof. The guide plate includes a plurality of micro guide holes opened therethrough.

Claims

1. An optical module comprising:

a planar microlens array having a plurality of microlenses formed in at least one surface thereof;

a planar transparent substrate for adjusting a conjugate ratio of the optical module, one surface of the transparent substrate being adhered to one surface of the planar microlens array, and a plurality of micro fitting recesses being formed in the other surface of the transparent substrate with each of the recesses being aligned to each of the microlenses; and

a guide substrate for optical fibers, the guide substrate being adhered to the other surface of the transparent substrate, and the guide substrate having a plurality of micro guide holes opened therein with each of the guide holes being aligned to each of the recesses.

2. The optical module of claim 1, wherein each of the guide holes is a tapered micro guide hole having an inlet and an outlet the diameter thereof is smaller than that of inlet.

3. The optical module of claim 2, further comprising a plurality of optical fibers each having a micro fitting convex portion to be fitted into one of the recesses, the micro fitting convex portion consisting of an end core portion exposed convexly of each of optical fibers.

4. The optical module of claim 1, 2 or 3, wherein the conjugate ratio is adjusted by varying the thickness of the transparent substrate.

5. The optical module of claim 4, wherein respective outer edge sizes of the planar microlens array, the planar transparent substrate, and the guide substrate are the same.

6. A method for assembling an optical module comprising the steps of:

preparing a planar microlens array having a plurality of microlenses formed in at least one surface thereof;

adhering one surface of a planar transparent substrate for adjusting a conjugate ratio of the optical module to one surface of the planar microlens array, the transparent substrate having a plurality of micro fitting recesses formed in the other surface thereof, in such a manner that the center position of each of the recesses is aligned to the center position of each of the microlenses; and

adhering one surface of a guide substrate for optical fibers to the other surface of the transparent substrate, the guide substrate having a plurality of micro guide holes opened therein, in such a manner that the center position of each of the guide holes is aligned to the center position of each of the recesses.

7. The method of claim 6, wherein each of the guide holes is a tapered micro guide hole having an inlet and an outlet the diameter thereof is smaller than that of inlet.

8. The method of claim 7, wherein the step of adhering the transparent substrate to the planar microlens array includes the steps of:

laying the transparent substrate on top of the planar microlens array in such a manner that respective outer edges of the transparent substrate and the planar microlens array are matched;

regulating the positional relation between the transparent substrate and the planar microlens array in such a manner that the center position of each of the recesses is aligned to the center position of each of the microlenses and

adhering the transparent substrate to the planar microlens array.

9. The method of claim 8, wherein the steps of adhering the guide substrate to the transparent substrate includes the steps of:

laying the guide substrate on top of the transparent substrate in such a manner that respective outer edges of these substrates are matched;

regulating the positional relation between the guide substrate and the transparent substrate in such a manner that the center position of each of the guide holes is aligned to the center position of each of the recesses; and

adhering the guide substrate to the transparent substrate.

10. The method of any one of claims 6-9, further comprising the steps of:

preparing a plurality of optical fibers each having a micro fitting convex portion consisting of an end core portion exposed convexly,

inserting the plurality of optical fibers into the guide holes, respectively; and

adhering the plurality of optical fibers to the recesses and guide holes.