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:
Jul. 20, 2004
Filed:
Jul. 27, 2001
Pirelli Cavi E Sistemi S.p.A., Milan, IT;
Abstract
An optical device for providing threshold and comparison functions. The device comprises first and second SOA's having respective first and second propagation paths along which the first and second optical signals, input as signals P (&lgr; ) and P (&lgr; ) travel in first and second forward directions. A feedback path is provided using couplers to interconnect the outputs of the SOA's. As a result, a portion of the optical signals output from each SOA is supplied backwards into the output of the other SOA as feedback optical control signals P (&lgr; ) and P (&lgr; ). The feedback optical control signals modulate the gain of the forwards travelling optical signals by cross gain modulation (XGM). In contrast to prior art devices, the optical control signal is supplied backwards into the SOA's in a counter-propagating configuration. This allows much shorter feedback path lengths to be achieved in comparison to what is possible with prior art co-propagating configurations. Consequently, much higher bit rates can be achieved. The device may also be implemented in planar waveguide technology.