Flat-top tunable filter

US9874698B2 · kind B2 · utility

Assignee

• Lumentum Operations LLC · US

Inventors

• Barthelemy Fondeur · San Jose, US
• Jinxi Shen · San Ramon, US
• Leonid Frenkel · Palo Alto, US
• Yimin Hua · Los Altos, US
• David R. Walker · Ottawa, CA
• Yu Zhang · Shanghai, CN
• Vlatko MILINKOVIC · Ottawa, CA

Key dates

• Filing date: May 11, 2016
• Grant date: Jan 23, 2018
• Expiry date: May 11, 2036

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04Q2011/0018
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A tunable PLC optical filter having sequentially connected thermally tunable Mach-Zehnder (MZ) interferometers is described. The cascade of MZ interferometers, each having a free spectral ranges matching ITU frequency grid spacing, are tuned so as to have a common passband centered on the frequency of the signal being selected, while having at least one of the stopbands centered on any other ITU frequency. Any other optical channel that may be present at any other ITU frequency is suppressed as a result. Another MZ interferometer in series with the cascade of interferometers including an asymmetric or variable coupler, is tuned to have low transmission at the center frequency of the selected optical channel.