Broadband mode converter

• US 6,628,859 B2
• Filed: 03/22/2001
• Issued: 09/30/2003
• Est. Priority Date: 03/22/2001
• Status: Expired due to Term

• Current Assignee: Qorvo US, Inc. (Qorvo, Inc.)
• Original Assignee: TriQuint Technology Holding Co (Qorvo, Inc.)
• Inventors: Huang, Lin, Judkins, Justin Boyd
• Primary Examiner(s): ULLAH, AKM E
• Application Number:
  US09/815,142
• Publication Number:
  US 20030048986A1
• Time in Patent Office: 922 Days
• Field of Search: 385/28-38, 385/147, 385/129-133, 372/50, 333/21.R, 333/113
• US Class Current: 385/28
• CPC Class Codes: G02B 6/14 Mode converters
• CPC Class Codes: G02B 6/2826 using mechanical machining means for shaping of the couplers, e.g. grinding or polishing grinding, polishing in general B24
• CPC Class Codes: G02B 6/29376 coupling light guides for controlling wavelength dispersion, e.g. by concatenation of two light guides having different dispersion properties dispersion managed optical transmission systems H04B10/25253
• CPC Class Codes: H04J 14/04 Mode multiplex systems

Abstract

A mode converter for converting an optical signal from a first propagation mode (e.g., LP₀₁) to a second propagation mode (e.g., LP₀₂). The mode converter includes a first waveguide supporting a first mode of propagation. The mode converter also includes a second waveguide supporting a second mode of propagation. The first and second waveguides each having a group index characteristic, wherein the first group index characteristic is matched with the second group index characteristic such that electromagnetic energy propagating through the first waveguide at the first mode couples to the second waveguide at the second mode.

Claims

1. A mode converter comprising:

a first waveguide for supporting the propagation of electromagnetic energy at a first mode; and

a second waveguide for supporting the propagation of electromagnetic energy at a second mode, the first and second waveguides each having a group index characteristic, wherein the first group index characteristic is matched with the second group index characteristic such that electromagnetic energy propagating through the first waveguide at the first mode couples to the second waveguide at the second mode.

2. The mode converter of claim 1, wherein the first waveguide comprises a single mode optical fiber, and the second waveguide comprises a multi-mode optical fiber.

3. The mode converter of claim 2, wherein the first and second and group index characteristics are matched by matching the slope of an LP₀₁ mode propagation constant of a single-mode optical fiber with the slope of an LP₀₂ mode propagation constant of a multi-mode optical fiber.

4. The mode converter of claim 2, wherein first and second and group index characteristics are matched within +/−

5 percent.

5. The mode converter of claim 2, further comprising a bandwidth of 40 nm at a coupling efficiency of at least 97%.

6. An optical communication system for an optical signal, the optical communication system comprising:

an input single mode optical fiber for supporting a first mode of propagation of the optical signal; and

a mode converter for converting the mode of propagation of the optical signal from the first mode to a second mode, the mode converter comprising;

a first optical coupling fiber for supporting the first mode of propagation, the first optical coupling fiber having a first group index characteristic; and

a second optical coupling fiber for supporting at least the second mode of propagation, the second optical coupling fiber having a group index characteristic, wherein the first and second group index characteristics match such that the optical signal propagating through the first optical coupling fiber at the first mode propagates through the second optical coupling fiber at the second mode.

7. The optical communication system of claim 6, wherein the first optical coupling fiber comprises a single mode optical fiber, and the second optical coupling fiber comprises a multi-mode optical fiber.

8. The optical communication system of claim 7, wherein the first and second and group index characteristics are matched by matching the slope of an LP₀₁ mode propagation constant of a single-mode optical fiber with the slope of an LP₀₂ mode propagation constant of a multi-mode optical fiber.

9. The optical communication system of claim 7, wherein first and second and group index characteristics are matched within +/−

5 percent.

10. The optical communication system of claim 7, further comprising a bandwidth of 40 nm at a coupling efficiency of at least 97%.

11. A dispersion compensation system for an optical signal, the dispersion compensation system comprising:

an input single mode optical fiber for supporting the propagation of a first mode of the optical signal;

a dispersion compensating optical fiber supporting the propagation of at least a second mode of the optical signal; and

a mode converter for converting the mode of propagation of the optical signal from the first mode to the second mode, the mode converter comprising;

a first optical coupling fiber for supporting the first mode of propagation, the first optical coupling fiber having a first group index characteristic; and

a second optical coupling fiber for supporting at least the second mode of propagation, the second optical coupling fiber having a second group index characteristic, wherein the first and second group index characteristics match such that the optical signal propagating through the first optical coupling fiber at the first mode propagates through the second optical coupling fiber at the second mode.

12. The dispersion compensation system of claim 11, wherein the first optical coupling fiber comprises a single mode optical fiber, and the second optical coupling fiber comprises a multi-mode optical fiber.

13. The dispersion compensation system of claim 12, wherein the first and second and group index characteristics are matched by matching the slope of an LP₀₁ mode propagation constant of a single-mode optical fiber with the slope of an LP₀₂ mode propagation constant of a multi-mode optical fiber.

14. The dispersion compensation system of claim 12, wherein first and second and group index characteristics are matched within +/−

5 percent.

15. The dispersion compensation system of claim 12, further comprising a bandwidth of 40 nm at a coupling efficiency of at least 97%.

16. A system for multiplexing at least two optical component signals of differing modes onto an input optical signal having an input mode of propagation, the system comprising:

an input waveguide for propagating the input optical signal; and

at least a two mode converters, each mode converter converting the mode of propagation of the input optical signal from the input mode to one of the differing modes, each mode converter comprising;

a first optical coupling fiber for supporting the first mode of propagation, the first optical coupling fiber having a first group index characteristic; and

a second optical coupling fiber for supporting at least the one of the differing modes of propagation, the second optical coupling fiber having at least one of differing group index characteristics, wherein the first and the at least one of the differing group index characteristics match such that the optical signal propagating through the first optical coupling fiber at the first mode propagates through the second optical coupling fiber at the one of the differing modes.

17. The system of claim 16, wherein the first optical coupling fiber comprises a single mode optical fiber, and the second optical coupling fiber comprises a multi-mode optical fiber.

18. The system of claim 17, wherein the first and second and group index characteristics are matched by matching the slope of an LP₀₁ mode propagation constant of a single-mode optical fiber with the slope of another mode propagation constant of a multi-mode optical fiber.

19. The system of claim 17, wherein first and second and group index characteristics are matched within +/−

5 percent.

20. The system of claim 17, further comprising a bandwidth of 40 nm at a coupling efficiency of at least 97%.