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:
Oct. 25, 1994
Filed:
Oct. 20, 1992
Peter A Schulz, Andover, MA (US);
Massachusetts Institute of Technology, Cambridge, MA (US);
Abstract
An optical frequency discriminator having enhanced linearity is provided, which discriminator may be utilized in FM communications systems or in other applications. The discriminator has two interferometers with the optical path length difference for the first interferometer being .DELTA.L and for the second interferometer being m.DELTA.L where m>1. The optical FM signal is applied in parallel to both optical interferometers with approximately m.sup.3 times as much of the signal being applied to the first interferometer as to the second interferometer. Each interferometer has an output signal versus frequency characteristic with a substantially linear region about a center frequency, which center frequency is approximately equal to the center frequency of the input optical signal. The outputs from the interferometers are combined in a manner such as the difference in absolute value of the linear region characteristic slopes is obtained, the resulting output being a discriminated output which is substantially linear over an enhanced FM range.