Optical add/drop device and assemly, and communications network node

Patent metadata

Field	Value
Publication number	US-2021396933-A1
Application number	US-201817289984-A
Country	US
Kind code	A1
Filing date	Oct 30, 2018
Priority date	Oct 30, 2018
Publication date	Dec 23, 2021
Grant date	—

Abstract

An optical add/drop device ( 100 ) comprising: a common port ( 102 ); an add port ( 106 ); a first wavelength selective optical filter ( 110 ) configured to: receive an optical signal at an add wavelength from the add port and transmit said optical signal at the add wavelength towards the common port; and receive optical signals from the common port and reflect optical signals not at the add wavelength; a second wavelength selective optical filter ( 114 ) configured to receive said optical signals from the common port reflected by the first wavelength selective optical filter and transmit an optical signal at a drop wavelength, different to the add wavelength; a drop port ( 116 ); and an optical waveguide ( 118 ) configured receive said optical signal at the drop wavelength transmitted by the second wavelength selective optical filter and route said optical signal to the drop port.

First claim

1 . An optical add/drop device comprising:
a common port; an add port; a first wavelength selective optical filter configured to: receive an optical signal at an add wavelength from the add port and transmit said optical signal at the add wavelength towards the common port; and receive optical signals from the common port and reflect optical signals not at the add wavelength; a second wavelength selective optical filter configured to receive said optical signals from the common port reflected by the first wavelength selective optical filter and transmit an optical signal at a drop wavelength, different to the add wavelength; a drop port; and an optical waveguide configured receive said optical signal at the drop wavelength transmitted by the second wavelength selective optical filter and route said optical signal to the drop port.

2 . An optical add/drop device according to claim 1 , further comprising an express port and wherein:
the second wavelength selective filter is additionally configured to: receive said optical signals from the common port reflected by the first wavelength selective optical filter and reflect optical signals not at the drop wavelength towards the express port; and receive optical signals from the express port and reflect optical signals not at the drop wavelength; and the first wavelength selective filter is additionally configured to receive said optical signals from the express port reflected by the second wavelength selective filter and reflect said optical signals towards the common port.

3 . An optical add/drop device according to claim 1 , wherein the optical signals propagate in free space between the common port and the first wavelength selective filter and between the first wavelength selective filter and the second wavelength selective filter.

4 . An optical add/drop device according to claim 2 , wherein the optical signals propagate in free space between the express port and the second wavelength selective filter and between the first wavelength selective filter and the second wavelength selective filter.

5 . An optical add/drop device according to claim 1 , wherein the optical waveguide has a curved path from the second wavelength selective optical filter to the drop port.

6 . An optical add/drop device according to claim 1 , wherein the optical waveguide comprises an optical fibre mounted in an optical ferule having a curved bore.

7 . An optical add/drop device according to claim 1 , wherein the first wavelength selective filter is configured to transmit a first wavelength channel of a wavelength grid of the communications network and reflect all other wavelength channels of said wavelength grid and the second wavelength selective filter is configured to transmit a second wavelength channel of said wavelength grid, different to the first wavelength channel, and reflect all other wavelength channels of said wavelength grid.

8 . An optical add/drop device according to claim 1 , wherein at least one of the first wavelength selective filter and the second wavelength selective filter comprises an optical thin film filter comprising a multi dielectric periodic structure.

9 . An optical add/drop device according to claim 1 , further comprising a mirror configured to reflect all wavelength channels received from the first wavelength selective filter towards the second wavelength selective filter and to reflect all wavelength channels received from the second wavelength selective filter towards the first wavelength selective filter.

10 . An optical add/drop device according to claim 1 , wherein the add port and the drop port comprise small form factor optical fibre connectors configured to be pluggable directly into complementary connector sockets on an optical transceiver module.

11 . An optical add/drop assembly comprising:
an optical add/drop device according to claim 1 ; and an optical transceiver module comprising an output port and an input port, wherein the optical transceiver module is configured to transmit an optical signal at the add wavelength from the output port and to receive an optical signal at the drop wavelength at the input port, and wherein the add port of the optical add/drop device is connected to the output port of the optical transceiver module and the drop port of the optical add/drop device is connected to the input port of the optical transceiver module.

12 . An optical add/drop assembly according to claim 11 , comprising a plurality of optical transceiver modules and a plurality of optical add/drop devices each connected to a respective one of the optical transceiver modules, wherein each said optical transceiver module-optical add/drop device pair is configured to operate at a respective one of a plurality of add wavelengths and a respective one of a plurality of drop wavelengths, and wherein the optical add/drop devices are connected in series with the common port and the express port of adjacent pairs of the optical add/drop devices being connected.

13 . An optical add/drop assembly according to claim 11 wherein the add port and the drop port comprise small form factor optical fibre connectors configured to be pluggable directly into complementary connector sockets on an optical transceiver module and wherein the output port and the input port of a said optical transceiver module comprise optical connector sockets configured to receive small form factor optical fibre connectors and wherein the add port and drop port small form factor optical fibre connectors of a said optical add/drop device are directly plugged into the output port and input port optical connector sockets of a said optical transceiver module

14 . A communications network node comprising an optical add/drop assembly according to claim 11 .

Assignees

• Ericsson Telefon Ab L M

Inventors

• Mosti Sergio
• Lanzone Sergio
• Assale Marco
• D'Incà Chaudio
• Deho Alberyto

Classifications

• H04B10/2589

  Bidirectional transmission · CPC title

• G02B6/4246

  Bidirectionally operating package structures · CPC title

• G02B6/29365 Primary

  in a multireflection configuration, i.e. beam following a zigzag path between filters or filtering operations · CPC title

• G02B6/29383

  Adding and dropping · CPC title

• H04J14/0206

  Express channels arrangements · CPC title