Combined splitter, isolator and spot-size converter

Patent metadata

Field	Value
Publication number	US-9563073-B2
Application number	US-201414316997-A
Country	US
Kind code	B2
Filing date	Jun 27, 2014
Priority date	Jun 27, 2014
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

An integrated and compact multifunctional optical isolator (i.e., a combined splitter, isolator, and spot-size converter), which is suitable for use in a TOSA, includes input optics including a first polarizer, a Faraday rotator, and a second polarizer. The input optics include a wedge having a partially reflective coating disposed on a first face thereof. The input beam is incident on the first face at a non-normal angle of incidence such light passing through the wedge is refracted to a second face of the wedge, which is tilted relative to the first face by a predetermined wedge angle. At least one of the non-normal angle of incidence and the predetermined wedge angle is determined dependence upon a refractive index of the wedge material and a target anamorphic magnification of the input beam of light.

First claim

What is claimed is:

1. A multifunctional optical isolator comprising:
an input port for transmitting an input beam of light;
input optics optically disposed between the input port and an output port, the input optics comprising a first polarizer for transmitting light having a first polarization;
a second polarizer optically disposed between the input optics and the output port oriented to transmit light having a second polarization, the first polarization being different than the second polarization; and
a non-reciprocal rotator optically disposed between the input optics and the second polarizer oriented to rotate a polarization of light transmitted therethrough such that light propagating in a forward propagating direction having the first polarization passes through the second polarizer to the output port, and light propagating in a backward propagation direction having the second polarization is not passed through the first polarizer to the input port,
wherein the input optics comprises a wedge having a partially reflective coating disposed on a first face thereof, the partially reflective coating for reflecting a first portion of the input beam of light away from the wedge and allowing a second portion of the input beam of light to pass into the wedge, the first face oriented to receive the input beam of light at a non-normal angle of incidence and refracting the second portion of the input beam of light to a second face of the wedge, the first face tilted relative to the second face by a predetermined wedge angle, at least one of the non-normal angle of incidence or the predetermined wedge angle determined in dependence upon a refractive index of a wedge material and a target anamorphic magnification of the input beam of light.

2. The multifunctional optical isolator of claim 1 , wherein the first polarization is parallel to a first axis and the second polarization is at 45° to the first axis.

3. The multifunctional optical isolator of claim 2 , wherein the second polarizer is an absorptive polarizer having a polarization axis substantially at 45° to the first axis, and the non-reciprocal rotator is a Faraday rotator for rotating the polarization of light transmitted from the input optics by 45°.

4. The multifunctional optical isolator of claim 3 , wherein the first polarizer is an absorptive polarizer having a polarization axis substantially parallel to the first axis, and wherein the wedge is a glass wedge coupled to the first polarizer.

5. The multifunctional optical isolator of claim 3 , wherein the first polarizer and the wedge are integrated in a single birefringent wedge, the birefringent wedge having an optic axis substantially parallel to the first axis.

6. The multifunctional optical isolator of claim 3 , wherein the wedge is formed from an isotropic material, and wherein the first polarizer and partially reflective coating are integrated in a single polarization dependent coating disposed on the first face.

7. The multifunctional optical isolator of claim 3 , wherein the wedge is formed from an isotropic material, and wherein the partially reflective coating includes the first polarizer.

8. The multifunctional optical isolator of claim 3 , wherein the wedge is formed from an isotropic material, and wherein the partially reflective coating provides partial reflection for p-polarized light and high reflection for s-polarized light.

9. The multifunctional optical isolator of claim 3 , wherein the wedge angle is between 10° and 50°.

10. The multifunctional optical isolator of claim 1 , wherein the input beam of light is a substantially collimated beam of light having an elliptical cross-section.

11. The multifunctional optical isolator of claim 1 , wherein the input optics, the non-reciprocal rotator, and the second polarizer are coupled together with a transparent epoxy.

12. The multifunctional optical isolator of claim 1 , wherein the input port is for optically coupling to a laser diode that provides the input beam of light, and the output port is for optically coupling to an optical fiber.

13. The multifunctional optical isolator of claim 12 , further comprising:
a first lens disposed between the laser diode and the input optics and a second lens disposed between the second polarizer and the optical fiber.

14. The multifunctional optical isolator of claim 12 , wherein the first face is oriented such that the first portion of the input beam of light is directed towards a monitor, the monitor configured to monitor at least one of a wavelength or a power of the input beam of light.

15. The multifunctional optical isolator of claim 12 , wherein the input optics, the non-reciprocal rotator, and the second polarizer form an integrated component for use in Transmit Optical Subassembly.

16. A multifunctional optical isolator comprising:
an input port for transmitting an input beam of light;
a first polarizer optically disposed between the input port and an output port oriented to transmit light having a first polarization, the first polarizer comprising a birefringent crystal having an optic axis substantially parallel to the first polarization, the birefringent crystal having a first face having a partially reflective coating disposed thereon, the partially reflective coating for reflecting a first portion of the input beam of light away from the birefringent crystal and allowing a second portion of the input beam of light to pass into the birefringent crystal, the first face oriented to receive the input beam of light at a non-normal angle of incidence and refract the second portion of the input beam of light to a second face of a wedge, the first face tilted relative to the second face by a predetermined wedge angle, at least one of the non-normal angle of incidence or the predetermined wedge angle determined in dependence upon a refractive index of the birefringent crystal and a target anamorphic magnification of the input beam of light;
a second polarizer optically disposed between the first polarizer and the output port oriented to transmit light having a second polarization, the first polarization being different than the second polarization; and
a non-reciprocal rotator optically disposed between the first polarizer and the second polarizer oriented to rotate a polarization of light transmitted therethrough such that light propagating in a forward propagating direction having the first polarization passes through the second polarizer to the output port, and light propagating in a backward propagation direction having the second polarization is not passed through the first polarizer to the input port.

17. The multifunction optical isolator of claim 16 , wherein the wedge angle is between 10° and 50°.

18. The multifunctional optical isolator of claim 16 , wherein the first polarizer, the non-reciprocal rotator, and the second polarizer form an integrated component for use in Transmit Optical Subassembly.

19. A multifunctional optical isolator comprising:
an input port for transmitting an input beam of light;
a first polarizer optically disposed between the input port and an output port oriented to transmit light having a first polarization, the first polarizer comprising a polarization dependent coating deposited on a first face of a wedge, the polarization dependent coating for reflecting a first portion of the input beam of light having the first polarization away from the wedge and allowing a second portion of the input beam of light having the first polarization to pass into the wedge, the first face oriented to receive

Assignees

• Lumentum Operations Llc

Inventors

• Xiong Wei
• Larson Michael C
• Li Zhaoming
• Zhou Fenhong

Classifications

• G02F1/093 Primary

  used as non-reciprocal devices, e.g. optical isolators, circulators (G02F1/0955 takes precedence) · CPC title

• G02B6/32

  having lens focusing means {positioned between opposed fibre ends (with lens being an integral part of the single fibre end G02B6/262)} · CPC title

• G02B6/4209

  Optical features · CPC title

• G02B6/4286

  Optical modules with optical power monitoring · CPC title

• G02B6/2746

  comprising non-reciprocal devices, e.g. isolators, FRM, circulators, quasi-isolators (magneto-optic non-reciprocal devices G02F1/093) · CPC title