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:
Oct. 23, 2001
Filed:
Jan. 21, 1998
Robert Roger Cordell, Middletown, NJ (US);
Paul Grabbe, Tinton Falls, NJ (US);
James John Ringo, Brick, NJ (US);
Tellium, Inc., Oceanport, NJ (US);
Abstract
A multi-wavelength optical receiver including multiple photodetectors receiving different ones of a multi-wavelength signal. For each wavelength-dedicated photodetector, a separate electronic receiver circuitry is provided including a current-to-voltage converting input transistor and an emitter-follower output transistor arranged as an operational amplifier with a feedback resistor. The circuit is improved by a cascode connection to the input transistor, by a reference to an analog ground rather than to a power supply line in both the photodiode and the cascode transistor, by the addition of capacitive shunts and a clamping transistor parallel to the feedback resistor in the feedback loop from the output transistor to the input transistor, by including positive and negative power supplies for the input and the output stages, by including multiple emitter followers in the output, by use of a differential second stage referenced to the analog ground, and by use of an output matching network that makes use of parasitic packaging inductances. Thereby, noise is reduce and inter-channel interference is minimized.