Fiber optic amplifier with active elements feedback circuit
AssigneeInternational Business Machines Corporation
InventorsDaniel M. Dreps, Raymond P. Rizzo
Life of this patent
Estimating the term…
Abstract
A differential transimpedance amplifier used in amplifying optical signals transmitted with a balanced code has a level restore circuit which integrates the digital output of the amplifier and feeds back the result to one of the differential inputs of the amplifier. The feedback signal removes imbalances from the amplifier output. The balanced amplifier output can then be processed by a clock reconstruction circuit to accurately sample the received optical signal with a low bit error rate.
Claims14
A receiver for recovering multibit binary digital messages from transmitted balanced code, comprising:
- a differential amplifier for amplifying received balanced code and supplying high and low digital output signals;
- and
- an active elements level restore circuit coupled to the digital output of the amplifier, said active elements level restore circuit comprising means for determining a pulse width difference between the high and low digital signals provided by said amplifier and means for integrating the pulse width difference and supplying said integrated pulse width difference to one of said inputs of said differential amplifier, so that a balanced digital output from said amplifier is achieved.
A fiber optic receiver for recovering multibit binary digital messages from optically transmitted balanced code comprising:
- a photo-detector circuit for converting the received optical signals into electrical signals;
- a differential amplifier AC coupled to the photo-detector circuit for amplifying the electrical signals and supplying high and low digital output signals;
- and an active elements level restore circuit coupled to the digital output of the amplifier, said active elements level restore circuit comprising means for determining a pulse width difference between the high and low digital signals provided by said amplifier and means for integrating the pulse width difference and supplying said integrated pulse width difference to one of said inputs of said differential amplifier, so that a balanced digital output from said amplifier is achieved.
Dependencies are inferred from the claim text.