Systems and methods for photonic polarization rotators

• US 10,209,448 B2
• Filed: 08/25/2016
• Issued: 02/19/2019
• Est. Priority Date: 06/08/2011
• Status: Active Grant

• Current Assignee: Skorpios Technologies Inc.
• Original Assignee: Skorpios Technologies Inc.
• Inventors: Dallesasse, John, Krasulick, Stephen B.
• Primary Examiner(s): Kianni, Kaveh C
• Application Number:
  US15/246,925
• Publication Number:
  US 20170108649A1
• Time in Patent Office: 908 Days
• Field of Search: 385 14, 385 43
• CPC Class Codes: G02B 2006/12061 Silicon
• CPC Class Codes: G02B 5/3058 comprising electrically conductive elements, e.g. wire grids, conductive particles
• CPC Class Codes: G02B 6/105 having optical polarisation effects
• CPC Class Codes: G02B 6/126 using polarisation effects G02B6/1226 takes precedence
• CPC Class Codes: G02B 6/26 Optical coupling means G02B6/36, G02B6/42 take precedence
• CPC Class Codes: G02B 6/2726 in or on light guides, e.g. polarisation means assembled in a light guide
• CPC Class Codes: G02B 6/2746 comprising non-reciprocal devices, e.g. isolators, FRM, circulators, quasi-isolators magneto-optic non-reciprocal devices G02F1/093
• CPC Class Codes: G02B 6/2766 Manipulating the plane of polarisation from one input polarisation to another output polarisation, e.g. polarisation rotators, linear to circular polarisation converters
• CPC Class Codes: G02F 1/0036 Magneto-optical materials
• CPC Class Codes: G02F 1/093 used as non-reciprocal devices, e.g. optical isolators, circulators G02F1/0955 takes precedence

Abstract

An integrated non-reciprocal polarization rotator comprises a substrate, a Faraday crystal, a first waveguide, and a second waveguide. The substrate has a recess extending to a predetermined depth. The Faraday crystal is mounted in the recess and optically coupled with the first waveguide and the second waveguide.

Claims

1. A photonic device comprising:

a substrate having a support surface and a device surface opposing the support surface, thereby defining a substrate thickness, wherein the substrate includes a fill region;

a Faraday crystal mounted in the fill region and having a first facet and a second facet opposing the first facet;

a first waveguide integrated on the substrate and optically coupled with the first facet of the Faraday crystal;

an index matching region disposed between the first waveguide and the first facet of the Faraday crystal; and

a second waveguide integrated on the substrate and optically coupled with the second facet of the Faraday crystal, wherein;

the Faraday crystal is a first Faraday crystal;

the fill region is a first fill region; and

the photonic device further comprises;

a second fill region in the substrate;

a second Faraday crystal mounted in the second fill region, the second Faraday crystal having a first facet and a second facet opposing the first facet;

a third waveguide integrated on the substrate and coupled with the first facet of the second Faraday crystal;

a fourth waveguide integrated on the substrate and coupled with the second facet of the second Faraday crystal;

a first beam splitter integrated on the substrate; and

a second beam splitter integrated on the substrate;

the first waveguide and the third waveguide are coupled with the first beam splitter; and

the second waveguide and the fourth waveguide are coupled with the second beam splitter.

2. The photonic device of claim 1, wherein the index matching region is a first index matching region and the photonic device further comprises a second index matching region disposed between the second waveguide and the second facet of the Faraday crystal.

3. The photonic device of claim 1 wherein the Faraday crystal is permanently polled.

4. The photonic device of claim 3 wherein the Faraday crystal comprises at least one of bismuth europium holmium gallium iron garnet or bismuth yttrium iron garnet.

5. The photonic device of claim 1 wherein the Faraday crystal comprises yttrium iron garnet or bismuth-doped iron garnet.

6. The photonic device of claim 5 further comprising a magnet.

7. The photonic device of claim 1 wherein the substrate comprises silicon.

8. The photonic device of claim 7 further comprising an insulating layer disposed between the substrate and the first waveguide;

and between the substrate and the second waveguide.

9. The photonic device of claim 8 further comprising an amorphous silicon layer disposed between the insulating layer and the Faraday crystal.

10. The photonic device of claim 1, wherein the first beam splitter, the second beam splitter, or both the first beam splitter and the second beam splitter are polarizing beam splitters.

11. The photonic device of claim 1, the photonic device further comprising a reciprocal polarization rotator, wherein:

the reciprocal polarization rotator is between the first waveguide and the first beam splitter; and

the reciprocal polarization rotator is integrated on the substrate.

12. The photonic device of claim 1, wherein:

the first beam splitter is further coupled with a fifth waveguide;

the fifth waveguide is integrated on the substrate; and

the fifth waveguide is an input port.

13. The photonic device of claim 1, the photonic device further comprising:

a first reciprocal polarization rotator, wherein;

the first reciprocal polarization rotator is between the first waveguide and the first beam splitter; and

the first reciprocal polarization rotator is integrated on the substrate; and

a second reciprocal polarization rotator, wherein;

the second reciprocal polarization rotator is between the third waveguide and the first beam splitter; and

the second reciprocal polarization rotator is integrated on the substrate.

14. The photonic device of claim 13, wherein:

the first reciprocal polarization rotator, the first waveguide, the first Faraday crystal, and the second waveguide are on a first optical path between the first beam splitter and the second beam splitter; and

the second reciprocal polarization rotator, the third waveguide, the second Faraday crystal, and the fourth waveguide are on a second optical path between the first beam splitter and the second beam splitter.