Fujitsu Corporation

Noah Gottfried

Christopher Mesibov

Idan Mandelbaum

James F Burnell

Sheng Wu

Corey Dayton

Joseph G Trotta

Richard Gammenthaler

Methods and systems for replicating high bandwidth current outputs from a photodetector or another current source include using a transimpedance amplifier (TIA) to directly generate a TIA voltage that is linear with optical power at the photodetector. The TIA voltage is used to generate a current that flows to a log amp, which generates a voltage that is linear with the optical power in dB. Additionally, offset cancellation is used at the TIA and at the log amp.

High bandwidth photodetector current replicator

Methods and systems for replicating current outputs from a photodetector include using a transimpedance (TIA) amplifier to directly generate a TIA output voltage that is linear with optical power at the photodetector. Additionally, a first logarithmic amplifier is used to generate a first output voltage from the photodetector current and a second logarithmic amplifier is used to generate a second voltage from a copy of the photodetector current. The first voltage and the second voltage may be linear in some cases with the optical power in decibels.

Triple output photodetector current replicator

Methods and systems for current amplification to improve optical amplifier performance may include equalizing a current level indicative of input optical power to an optical amplifier with a current level indicative of an output optical power level of the optical amplifier. In this manner, a first bandwidth of an input log amp may be matched with a second bandwidth of an output log amp in a gain control loop circuit to improve overall transient gain accuracy of the optical amplifier, irrespective of the input optical power. In this manner, the optical amplifier may be enabled to operate at a defined gain level even in the presence of transients in the input signal.

Current amplification to improve optical amplifier performance

A system may include a bus carrying signals, a frame pulse generator generating a generally periodic frame pulse signal having timing boundaries delineating consecutive timing periods and a frame pulse enable signal active for a portion of each timing period proximate to the timing boundaries and inactive otherwise, a first controlled buffer driving the frame pulse signal on the bus during durations in which the frame pulse enable signal is active to generate a modified frame pulse, a reference clock controller receiving the modified frame pulse via the bus and generating a reference clock enable signal in response to presence of the modified frame pulse, a reference clock generator generating a generally periodic reference clock signal, and a second controlled buffer driving the reference clock signal on the bus during durations in which the reference clock enable signal is active to generate a modified reference clock.

System and method for multiplexing a time-reference signal and a frequency-reference signal

EMI emissions generated by clock signals in a multi-slot electronic system are reduced by providing out-of-phase clock signals to alternate slots, which cause EMI emissions at typical testing distances and farther to be reduced. An electronic equipment comprises a plurality of slots, each slot operable to receive a clock signal and a plurality of phases of the clock signal, wherein a first phase of the clock signal is routed to a portion of the slots and a second phase of the clock signal is routed to a different portion of the slots. The second phase of the clock signal may be substantially 180&#xb0; out-of-phase with the first phase of the clock signal.

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Johnsonburg, NJ, United States of America

Noah Gottfried