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:
Apr. 17, 1990
Filed:
Mar. 24, 1989
Piero Gambini, Turin, IT;
Abstract
In a method for the automatic frequency control of semiconductor kasers, the signal emitted from the laser (1) is sent to an optical resonator (6) whose resonance frequency is modulated by a ramp signal, the signal outgoing from the resonator (6) is converted into an electrical signal, the derivative of such an electrical signal is calculated, the zero crossing of the derivative is detected, the ramp signal is sampled in corresponding with such a zero crossing, and the sample thus obtained is algebraically summed to a reference signal depenent on the nominal laser emission frequency, thus obtaining an error signal which is sent to devices (3) driving the laser (1). In case of a plurality of lasers (1a . . . 1n) the signals of which are wavelength multiplexed, the rame signal is sampled in correspondence with the derivative zero crossings corresponding with the emission frequencies of the individual lasers (1a . . 1n), and the samples thus obtained are compared with respective reference signals, obtaining a control signal for each laser. A device for implementing the method is also supplied (FIG. 1).