US 11,387,912 B2Granted

Wavelength converter and fiber optic transmission system

AssigneeFujitsu Limited

InventorsGoji Nakagawa, Tomoyuki Kato

Life of this patent

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Abstract

A wavelength converter that converts signal light and pump light into a light containing a new wavelength component using a nonlinear optical fiber, has a PBS for splitting incident light into a first polarized wave and a second polarized wave, a first polarization controller provided between the PBS and a first end of the nonlinear optical fiber, and a second polarization controller provided between the PBS and a second end of the nonlinear optical fiber, wherein in an optical loop connecting the PBS, the first polarization controller, the nonlinear optical fiber and the second polarization controller, the first polarized wave and a first component of the pump light travel through the nonlinear optical fiber in a first direction, and the second polarized wave and a second component of the pump light travel through the nonlinear optical fiber in a second direction opposite to the first direction.

Claims15

Dependent claims

A wavelength converter comprising:

an input port configured to input a signal light and a pump light;
an output port configured to output a converted light having a wavelength component different from the signal light and from the pump light;
a nonlinear optical fiber that has a nonlinear optical effect;
a polarization beam splitter configured to split incident light into a first polarized wave and a second polarized wave;
a first polarization controller provided between the polarization beam splitter and a first end of the nonlinear optical fiber a second polarization controller provided between the polarization beam splitter and a second end of the nonlinear optical fiber;
and
a control circuit configured to monitor a characteristic of the converted light and control a first amount of rotation of the first polarization controller and a second amount of rotation of the second polarization controller,
wherein in an optical loop connecting the polarization beam splitter, the first polarization controller, the nonlinear optical fiber, and the second polarization controller, the first polarized wave and a first component of the pump light travel through the nonlinear optical fiber in a first direction, and the second polarized wave and a second component of the pump light travel through the nonlinear optical fiber in a second direction opposite to the first direction, and
wherein the control circuit is connected to monitor to monitor power of the converted light output from the optical loop, and controls a polarization state of the converted light in the first direction with the first polarization controller and a polarization state of the converted light in the second direction with the second polarization controller based on the power of the converted light output from the optical loop.

6 more elements

A wavelength converter comprising:

an input port configured to input a signal light and a pump light;
an output port configured to output a converted light having a wavelength component different from the signal light and from the pump light;
a nonlinear optical fiber that has a nonlinear optical effect;
a polarization beam splitter configured to split incident light into a first polarized wave and a second polarized wave;
a first polarization controller provided between the polarization beam splitter and a first end of the nonlinear optical fiber;
and
a second polarization controller provided between the polarization beam splitter and a second end of the nonlinear optical fiber,
wherein in an optical loop connecting the polarization beam splitter, the first polarization controller, the nonlinear optical fiber, and the second polarization controller, the first polarized wave and a first component of the pump light travel through the nonlinear optical fiber in a first direction, and the second polarized wave and a second component of the pump light travel through the nonlinear optical fiber in a second direction opposite to the first direction,
wherein the wavelength converter has
an optical multiplexer/demultiplexer provided outside the optical loop and optically connected to the polarization beam splitter,
wherein the polarization beam splitter has a first port configured to input the signal light supplied from the optical multiplexer/demultiplexer, a second port configured to input the pump light, a third port configured to input the first polarized wave and the first component of the pump light into the optical loop in the first direction, and a fourth port configured to input the second polarized wave and the second component of the pump light into the optical loop in the second direction, and
wherein an output light of the optical loop is supplied from the first port to the optical multiplexer/demultiplexer, and the converted light is separated at and output from the optical multiplexer/demultiplexer.

9 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/952,776Filed 19 Nov 2020
Published: US 2022/0158741 A119 May 2022
Granted: 12 Jul 2022
Term ends: Not estimatedThe source records don’t support an estimate.

Classification13 codes

H04B 10/675
For controlling the input optical signal: for controlling the optical bandwidth of the input signal, e.g. spectral filtering
G02B 27/283
For polarising: used for beam splitting or combining
G02F 1/3519
Using an interferometer: of Sagnac type, i.e. nonlinear optical loop mirror [NOLM]
G02F 2/004
Demodulating light; Transferring the modulation of modulated light; Frequency-changing of light: transferring the modulation of modulated light,…