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:
May. 15, 1990
Filed:
Jul. 13, 1989
Yun C Chung, Aberdeen, NJ (US);
AT&T Bell Laboratories, Murray Hill, NJ (US);
Abstract
Heterodyne and homodyne lightwave communication systems require transmitter optical sources and receiver local oscillators to be locked to a particular frequency. In accordance with the present invention, each transmitter laser and each receiver local oscillator laser is independently and locally stabilized to the same absolute frequency standard using species exhibiting atomic or molecular absorption lines in the wavelength range of interest. Frequency stabilization of the lasers is achieved by employing an optogalvanic effect element in a feedback control loop with the laser. Absolute frequency standards are obtained using gas discharge tubes containing, for example, noble gases such as argon (1.2 .mu.m to 1.4 .mu.m) and krypton (1.4 .mu.m to 1.6 .mu.m) and the like. Standard synchronous detection and feedback control techniques are used to insure proper long-term frequency stability.