The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 26, 2013
Filed:
Sep. 23, 2008
Michael Cahill, Dedham, MA (US);
Michael Cahill, Dedham, MA (US);
Photop Aegis, Inc., Woburn, MA (US);
Abstract
An optical signal-to-noise ratio monitor includes a demodulator comprising an input that receives at least a portion of a phase modulated optical signal. The monitor also includes a delay interferometer with a periodic phase control that sweeps a differential delay of one arm of the interferometer through a plurality of differential optical phase shifts. The demodulator converts phase modulated optical signals to intensity modulated optical signals. A tunable optical filter continuously scans a transmission wavelength over a desired wavelength range in a time that allows more than one wavelength to be transmitted through an output of the tunable filter for each of the plurality of differential optical phase shifts. An optical detector detects the filtered optical signal and generates a corresponding electrical demodulation signal at an output. A processor determines an optical signal-to-noise ratio for the more than one wavelength of the optical signal.