OPTICAL MODULE AND METHOD FOR PRODUCING SAME

• US 20200132935A1
• Filed: 04/02/2018
• Published: 04/30/2020
• Est. Priority Date: 06/19/2017
• Status: Active Grant

• Current Assignee: Fujikura Limited
• Original Assignee: Fujikura Limited
• Inventors: Oda, Takuya
• Granted Patent: US 11,067,753 B2
• Time in Patent Office: Days
• CPC Class Codes: G02B 6/14 Mode converters
• CPC Class Codes: G02B 6/262 Optical details of coupling light into, or out of, or between fibre ends, e.g. special fibre end shapes or associated optical elements
• CPC Class Codes: G02B 6/30 for use between fibre and thin-film device
• CPC Class Codes: G02B 6/305 and having an integrated mode-size expanding section, e.g. tapered waveguide
• 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

Abstract

An optical module includes: a substrate-type optical waveguide device; and an optical fiber that guides light that enters or exits the waveguide device. Spot sizes w1 and w2 satisfy 1<w2/w1<α; w1 is a spot size: on an end surface of the substrate-type optical waveguide device, and of a waveguide mode guided through a core of the substrate-type optical waveguide device, w2 is a spot size: on an end surface of the optical fiber, and of a waveguide mode guided through a core of the optical fiber, and a is a spot size ratio w2/w1 at which an efficiency η(0) is equal to the efficiency η(0) when w2/w1=1.

Claims

1. An optical module comprising:

a substrate-type optical waveguide device; and

an optical fiber that guides light that enters or exits the substrate-type optical waveguide device wherein

spot sizes w1 and w2 satisfy 1<

w2/w1<

α

,

where

w1 is a spot size;

on an end surface of the substrate-type optical waveguide device, and

of a waveguide mode guided through a core of the substrate-type optical waveguide device,

w2 is a spot size;

on an end surface of the optical fiber, and

of a waveguide mode guided through a core of the optical fiber, and

α

is a spot size ratio w2/w1 at which an efficiency η

(0) is equal to the efficiency η

(0) when w2/w1=1, where the efficiency η

(0) is an efficiency of coupling between the substrate-type optical waveguide device and the optical fiber when an amount of axis misalignment between the core of the substrate-type optical waveguide device and the core of the optical fiber is 0.

2. The optical module according to claim 1, wherein

the spot sizes w1 and w2 satisfy β

<

w2/w1<

β

, where β

is a spot size ratio w2/w1 at which the efficiency η

(0) is at a maximum.

3. The optical module according to claim 1, wherein

the spot sizes w1 and w2 satisfy 1<

w2/w1<

1.662×

w1<sup>−

3.554</sup>+1.

4. The optical module according to claim 3, wherein

the spot sizes w1 and w2 satisfy 0.058w1⁴−

0.668w1³+2.829w1²−

5.268w1+4.706<

w2/w1<

1.662×

w1<sup>−

3.554</sup>+1.

5. The optical module according to claim 1, wherein

the spot sizes w1 and w2 satisfy 1<

w2/w1<

4.195×

w1<sup>−

3.168</sup>+1.

6. The optical module according to claim 5, wherein

the spot sizes w1 and w2 satisfy 0.070w1⁴−

0.827w1³+3.646w1²−

7.229w1+6.614<

w2/w1<

4.195×

w1<sup>−

3.168</sup>+1.

7. The optical module according to claim 1, wherein

the spot sizes w1 and w2 satisfy 1<

w2/w1<

9.253×

w1<sup>−

2.733</sup>+1.

8. The optical module according to claim 7, wherein

the spot sizes w1 and w2 satisfy 0.093w1⁴−

1.097w1³+4.855w1²−

9.872w1+9.217<

w2/w1<

9.253×

w1<sup>−

2.733</sup>+1.

9. The optical module according to claim 1, wherein

the spot sizes w1 and w2 satisfy 1<

w2/w1<

(0.506z−

0.867)×

w1<sup>(0.0531z−

3.7715)</sup>+1,

where z is an inter-end-surface distance between the substrate-type optical waveguide device and the optical fiber.

10. The optical module according to claim 9, wherein

the spot sizes w1 and w2 satisfy (0.0023z+0.0465)w1⁴−

(0.0284z+0.533)w1³+(0.133z+2.2245)w1²−

(0.3008z+3.9465)w1+(0.295z+3.4045)<

w2/w1<

(0.506z−

0.867)×

w<sup>(0.0531z−

3.7715)</sup>+1.

11. The optical module according to claim 1, wherein

the spot size w1 is less than or equal to 3 μ

m.

12. A method for producing an optical module that comprises a substrate-type optical waveguide device and an optical fiber that guides light that enters or exits the substrate-type optical waveguide device, the method comprising:

setting spot sizes w1 and w2 to satisfy 1<

w2/w1<

α

,

where

w1 is a spot size;

on an end surface of the substrate-type optical waveguide device, and

of a waveguide mode guided through a core of the substrate-type optical waveguide device,

w2 is a spot size;

on an end surface of the optical fiber, and

of a waveguide mode guided through a core of the optical fiber, and

α

is a spot size ratio w2/w1 at which an efficiency η

(0) is equal to the efficiency η

(0) when w2/w1=1, where the efficiency η

(0) is an efficiency of coupling between the substrate-type optical waveguide device and the optical fiber when an amount of axis misalignment between the core of the substrate-type optical waveguide device and the core of the optical fiber is 0.

13. The method according to claim 12, wherein

the spot sizes w1 and w2 satisfy β

<

w2/w1<

α

, where β

is a spot size ratio w2/w1 at which the efficiency η

(0) is at a maximum.