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:
Jan. 24, 1995
Filed:
Mar. 21, 1994
Ingrid Z Van de Voorde, Dilbeek, BE;
Denis J Mestdagh, Brussels, BE;
Gert Van der Plas, Merchtem, BE;
Christiaan H Sierens, Kontich, BE;
Willem J Verbiest, Sint Gillis Waas, BE;
Alcatel N.V., Amsterdam, NL;
Abstract
The system includes two transmitters (T1, T2) and two receivers (R1, R2). One transmitter (T1) may include a wavelength tunable laser, sending an FSK optical signal (OS1) which has a constant intensity. In a first receiver (R1) this FSK optical signal (OS1) is transformed into an IM signal (OS1') by an optical pass band filter. This IM signal (OS1') is then detected by a first direct detection receiver (DM). In a second direct detection receiver (R2) the FSK optical signal (OS1) is not detected, since it has constant intensity. A second transmitter (T2) includes a Fabry Perot laser or a LED with a broad linewidth, sending an IM optical signal (OS2). This IM optical signal (OS2) is detected by the second direct detection receiver (R2). It is not detected by the first direct detection receiver (DM), because it is strongly attenuated when passing through the narrow bandpass optical filter (TM) before being applied to the first direct detection receiver. This system is especially advantageous in bidirectional optical transmission systems, due to its inherent insensitivity to reflections.