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:
Dec. 31, 1991
Filed:
Dec. 20, 1989
Ivan P Kaminow, Holmdel, NJ (US);
AT&T Bell Laboratories, Murray Hill, NJ (US);
Abstract
An N.times.N passive star coupler can be used to provide a high performance optical data network to interconnect many users at gigabit rates. Ignoring excessive losses, a signal incident on any input port is divided equally between all of the output ports. The average power at all of the input ports N of the star is equal to the average power at all of the output ports N. But, the power per channel at each output port is equal to only 1/N of the applied power. This loss which is due to splitting cannot be recovered by an amplifier at either the input port or the output port of the star coupler unless the amplifier saturation power is greater than the transmitter power. This invention solves the problem of amplifier saturation. Briefly, a discrete optical frequency signal which, when combined in the star coupler produces identical frequency division multiplex spectra at each output port is applied to each input port of the passive star coupler and tunable fiber Fabry-Perot filters are coupled to the output ports of the star coupler. The optical filters select the various channels. An amplifier is positioned downstream of each optical filter. By placing the amplifiers after the optical filter, the power level applied to the amplifier is substantially 1/(2N) of the transmitter power and saturation of the amplifier is minimized as a constraint.