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:
Apr. 05, 1989
Thirumala R Halemane, Howell, NJ (US);
Bartley C Johnson, Cranbury, NJ (US);
Robert M Jopson, Rumson, NJ (US);
AT&T Bell Laboratories, Murray Hill, NJ (US);
Abstract
Briefly, in this invention, the output optical power of an optical amplifier is determined by detecting and measuring the electrical signal induced on the bias lead of the optical amplifier when an optical data stream with additional amplitude modulation passes through the optical amplifier. This additional amplitude modulation can consist of a base band signal, a pilot tone and/or a sub-carrier which is amplitude modulated, frequency modulated or phase modulated. The modulation depth and bandwidth of the additional amplitude modulation should be kept small enough that the data stream is not excessively affected. The induced electrical signal provides a measurement of the optical power at the output facet of the optical amplifier. Control of the output power of the optical amplifier is effected by controlling the bias current applied to the bias lead of the optical amplifier. Thus, the output power of an optical amplifier can be monitored and telemetry signals can be received without interception of the data stream. The additional amplitude modulation of the data stream can be effected at the transmitter or by modulation of the bias current of an optical amplifier for transmission downstream. With this invention, no optical power is lost when the output power generated by an optical amplifier is monitored and modulation of the data stream can be effected without the use of additional optical components.