IP Library › Granted Patent US 12,552,703
Granted Patent B2
US 12,552,703 · App. 18/353,414 · Granted Feb 17, 2026

Methods for optimizing graded index fiber length to improve image quality

Inventors: Richard D. Faulhaber (San Carlos, CA); Patrick Gregg (Sunnyvale, CA); Martin H. Muendel (Oakland, CA)
Assignee: Lumentum Operations LLC
C03B37/14C03B37/15G02B6/0288G02B6/2552G02B6/268G02B6/2848C03B2203/40G02B6/262
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Quick Facts
Patent No.
US 12,552,703
App. No.
18/353,414
Granted
Feb 17, 2026
Kind
B2
Abstract

In some implementations, a fiber processing machine may receive an optical assembly comprising an input fiber, an output fiber, and a graded index fiber spliced between the input fiber and the output fiber, wherein the graded index fiber has a pitch length and a processed length. A light source may deliver input light into an input end of the input fiber while one or more components monitor output light at an output end of the output fiber. The fiber processing machine may alter a core diameter and the processed length of the graded index fiber until one or more measurements of the output light at the output end of the output fiber indicate that the output light is a perfect image of the input light.

Claims (55)

1 . A method for manufacturing a graded index fiber, comprising:

receiving an optical assembly comprising an input fiber, an output fiber, and a graded index fiber spliced between the input fiber and the output fiber,

wherein the graded index fiber has a pitch length and a processed length;

delivering input light into an input end of the input fiber;

monitoring output light at an output end of the output fiber, wherein the monitoring comprises actively monitoring the output light; and

tapering the graded index fiber while actively monitoring the output light until one or more measurements of the output light at the output end of the output fiber indicate that the output light is a perfect image of the input light,

wherein the processed length of the graded index fiber is N times the pitch length when the one or more measurements indicate that the output light is a perfect image of the input light, where N is an integer, a half-integer, or a quarter-integer.

2 . The method of claim 1 ,

wherein tapering the graded index fiber comprises increasing the processed length of the graded index fiber.

3 . The method of claim 1 ,

wherein tapering the graded index fiber comprises reducing a core diameter of the graded index fiber.

4 . The method of claim 3 ,

wherein reducing the core diameter of the graded index fiber causes the pitch length to be reduced.

5 . The method of claim 1 ,

wherein tapering the graded index fiber comprises increasing the processed length of the graded index fiber and reducing a core diameter of the graded index fiber.

6 . The method of claim 1 ,

wherein the one or more measurements of the output light are monitored in a near field.

7 . The method of claim 1 ,

wherein the one or more measurements of the output light are monitored in a far field.

8 . The method of claim 1 ,

wherein the one or more measurements are based on an output power from a core of the output fiber and an output power from a cladding of the output fiber.

9 . A method for manufacturing a graded index fiber, comprising:

receiving an optical assembly comprising an input fiber, an output fiber, and a graded index fiber spliced between the input fiber and the output fiber,

wherein the graded index fiber has a pitch length and a processed length;

delivering input light into an input end of the input fiber;

monitoring output light at an output end of the output fiber, wherein the monitoring comprises actively monitoring the output light; and

expanding a core diameter of the graded index fiber while shortening the processed length of the graded index fiber and actively monitoring the output light until one or more measurements of the output light at the output end of the output fiber indicate that the output light is a perfect image of the input light,

wherein the processed length of the graded index fiber is N times the pitch length when the one or more measurements indicate that the output light is a perfect image of the input light, where N is an integer, a half-integer, or a quarter-integer.

10 . The method of claim 9 ,

wherein the core diameter and the processed length of the graded index fiber are altered independently from one another.

11 . The method of claim 9 ,

wherein the one or more measurements of the output light are monitored in a near field.

12 . The method of claim 9 ,

wherein the one or more measurements of the output light are monitored in a far field.

13 . The method of claim 9 ,

wherein the one or more measurements are based on an output power from a core of the output fiber and an output power from a cladding of the output fiber.

14 . A method for manufacturing a graded index fiber, comprising:

receiving an optical assembly comprising an input fiber, an output fiber, and a graded index fiber spliced between the input fiber and the output fiber,

wherein the graded index fiber has a pitch length and a processed length;

delivering input light into an input end of the input fiber;

monitoring output light at an output end of the output fiber, wherein the monitoring comprises actively monitoring the output light; and

altering a core diameter and the processed length of the graded index fiber while actively monitoring the output light until one or more measurements of the output light at the output end of the output fiber indicate that the output light is a perfect image of the input light,

wherein the processed length of the graded index fiber is N times the pitch length when the one or more measurements indicate that the output light is a perfect image of the input light, where N is an integer, a half-integer, or a quarter-integer.

15 . The method of claim 14 ,

wherein altering the core diameter and the processed length of the graded index fiber comprises reducing the core diameter and increasing the processed length of the graded index fiber.

16 . The method of claim 14 ,

wherein altering the core diameter and the processed length of the graded index fiber comprises expanding the core diameter and shortening the processed length of the graded index fiber.

17 . The method of claim 14 ,

wherein the core diameter and the processed length of the graded index fiber are altered independently from one another.

18 . The method of claim 14 ,

wherein the one or more measurements of the output light are monitored in a near field.

19 . The method of claim 14 ,

wherein the one or more measurements of the output light are monitored in a far field.

20 . The method of claim 14 ,

wherein the one or more measurements are based on an output power from a core of the output fiber and an output power from a cladding of the output fiber.

Assignments (2)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Dec 22, 2025
From: LUMENTUM OPERATIONS LLC
To: WELLS FARGO BANK, NATIONAL ASSOCIATION, AS COLLATERAL AGENT
Reel/Frame 074974/0001 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jul 18, 2023
From: FAULHABER, RICHARD D.; GREGG, PATRICK; MUENDEL, MARTIN H.
To: LUMENTUM OPERATIONS LLC
Reel/Frame 064294/0662 →
Continuity (2)
Provisional Application 63499635 · May 2, 2023
Related Publication 20240368021A1 · Nov 7, 2024
References Cited (8)
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US 20170017036A1 · Botheroyd · 2017 [cited by examiner]
US 20190094469A1 · Mouri · 2019 [cited by examiner]
Analysis of the use of tapered graded-index polymer optical fibers for refractive-index sensors, Optics Express, vol. 16, No. 21, pp. 16616-16631, Oct. 13, 2008 (Year: 2008). [cited by examiner]
Robust Mode Matching between Structurally Dissimilar Optical Fiber Waveguides, ACS Photonics, vol. 8, pp. 857-863, 2021 (Year: 2021). [cited by examiner]