Patent ID: 7218865
Filing Date: 2007-05-15
Classification: H04L

Abstract:
1. A burst-mode optical receiver of a differential-output structure comprising: a trans-impedance amplifier for converting currents indicative of burst-mode signals into voltage signals; a bottom-level detector for detecting the bottom level of output signals from the trans-impedance amplifier; a top-level detector for detecting the top level of output signals from the trans-impedance amplifier; an automatic gain controller coupled to the bottom-level detector for automatically adjusting a gain of the signal output from the bottom level in order to prevent the output signals of the trans-impedance amplifier from being distorted; a pair of resistors coupled to the outputs of the bottom- and top-level voltages for generating a signal-reference voltage, one side of each resistor coupled to the bottom- and top-level detectors and the other sides of each resistor coupled to each other; and, a differential buffer for receiving outputs from the trans-impedance amplifier and the signal-reference voltage generated by the pair of resistors and is operative to eliminate offsets generated from the bottom- and top-level detectors, wherein the automatic gain controller further comprises a signal-level-determining section for determining whether or not a signal is present by analyzing the bottom level from the bottom-level detector, a drive transistor for activating according to the determined resultant of the signal-level-determining section, and at least one transistor for indicating whether or not the signal is present by means of capacitors, which carry out charging/discharging voltage applied by the drive transistor.