Method for adjusting optical receiver and apparatus for adjusting polarization of optical receiver

Patent metadata

Field	Value
Publication number	US-9544063-B2
Application number	US-201514606687-A
Country	US
Kind code	B2
Filing date	Jan 27, 2015
Priority date	Jan 28, 2014
Publication date	Jan 10, 2017
Grant date	Jan 10, 2017

Abstract

An optical receiver is disclosed. The optical receiver includes a polarization holding fiber configured to receive a light emitted from a light source and a polarizer configured to be irradiated with the light output from the polarization holding fiber. A method for adjusting the optical receiver comprises: inputting a plurality of lights having different wavelengths to a polarization holding fiber; detecting intensities of a plurality of lights output from the polarization holding fiber; calculating an adjustment value for an angle of the polarization holding fiber based on a ratio between the detected intensities of the plurality of lights; and adjusting the angle of the polarization holding fiber based on the calculated adjustment value.

First claim

What is claimed is:

1. A method for adjusting an optical receiver including a polarization holding fiber configured to receive a light emitted from a light source and a polarizer configured to be irradiated with the light output from the polarization holding fiber, the method comprising:
inputting a plurality of lights having different wavelengths to the polarization holding fiber;
detecting intensities of the plurality of lights output from the polarization holding fiber;
calculating an adjustment value for an angle of the polarization holding fiber based on a ratio of the detected intensities of the plurality of lights; and
adjusting the angle of the polarization holding fiber based on the calculated adjustment value.

2. The method for adjusting an optical receiver according to claim 1 ,
wherein each of the plurality of lights output from the polarization holding fiber is adjusted in polarization so that light receiving sensitivity of the optical receiver is maximum.

3. The method for adjusting an optical receiver according to claim 1 ,
wherein, in a case where: the adjustment value is an angle θ; a highest intensity among the detected intensities of the plurality of lights is Pmax; and a lowest intensity among the detected intensities of the plurality of lights is Pmin, the angle θ is calculated from formula (1) as follows,
cos 2θ=√{square root over ( P min/ P max)}  (1).

4. The method for adjusting an optical receiver according to claim 1 ,
wherein the adjustment value is an amount of offset between a polarization angle of the polarization holding fiber and a polarization angle of the polarizer, and
wherein the adjusting of the angle of the polarization holding fiber includes reducing the amount of offset.

5. The method for adjusting an optical receiver according to claim 1 , further comprising: securing the polarization holding fiber with the angle being adjusted.

6. The method for adjusting an optical receiver according to claim 1 , further comprising: connecting the polarization holding fiber to the optical receiver.

7. An apparatus for adjusting polarization of an optical receiver comprising:
a polarization holding fiber configured to receive a light emitted from a light source;
a polarizer configured to be irradiated with the light output from the polarization holding fiber;
a polarization controller configured to adjust an angle of the polarization holding fiber; and
a control unit configured to control the polarization controller,
wherein, after the control unit detects intensities of a plurality of lights having different wavelengths and being output from the polarization holding fiber, the control unit is configured to calculate an adjustment value for an angle of the polarization holding fiber based on a ratio between the detected intensities of the plurality of lights, and
wherein the polarization controller is configured to adjust the angle of the polarization holding fiber based on the calculated adjustment value.

8. The apparatus for adjusting polarization of an optical receiver according to claim 7 ,
wherein each of the plurality of lights output from the polarization holding fiber is adjusted by the polarization controller so that light receiving sensitivity of the optical receiver is maximum.

9. The apparatus for adjusting polarization of an optical receiver according to claim 7 ,
wherein, in a case where: the adjustment value is an angle θ; a highest intensity among the detected intensities of the plurality of lights is Pmax; and a lowest intensity among the detected intensities of the plurality of lights is Pmin, the angle θ is calculated from formula (1), and
wherein the polarization controller is configured to adjust the angle of the polarization holding fiber based on the angle θ as follows,
cos 2θ=√{square root over ( P min/ P max)}  (1).

10. The apparatus for adjusting polarization of an optical receiver according to claim 7 ,
wherein the adjustment value is an amount of offset between a polarization angle of the polarization holding fiber and a polarization angle of the polarizer, and
wherein the polarization controller is configured to make adjustment to reduce the amount of offset of the angle of the polarization holding fiber.

Assignees

• Sumitomo Electric Industries

Inventors

• Tateiwa Yoshihiro

Classifications

• G02B6/4213 Primary

  the intermediate optical elements being polarisation selective optical elements (G02B6/27 takes precedence) · CPC title

• G02B6/2766

  Manipulating the plane of polarisation from one input polarisation to another output polarisation, e.g. polarisation rotators, linear to circular polarisation converters · CPC title

• H04B10/6162 Primary

  Compensation of polarization related effects, e.g., PMD, PDL · CPC title

• H04B10/6151

  comprising a polarization controller at the receiver's input stage · CPC title

• H04B10/671

  for controlling the input optical signal · CPC title