Patent ID: 6519068
Filing Date: 2003-02-11
Classification: H04B

Abstract:
A circuit in an optical communication system that includes a laser which produces an optical signal, for stabilizing a wavelength of the optical signal by increasing a signal-to-noise ratio of the circuit and for outputting a wavelength-stabilized electrical control signal, for use in controlling the laser, wherein the circuit has a characteristic input capacitance produced by circuit elements in the system and that defines a characteristic impedance for the system at an electrical input node of the circuit, and wherein the optical signal is converted to an electrical signal having an electrical representation of the noise and wavelength of the optical signal, comprising:a receiver having a gain, an input node for receiving the electrical signal and an output node and operable for amplifying the received electrical signal and for outputting the amplified electrical signal at the output node for use in a feedback loop to create the electrical control signal for optical wavelength stabilization; a feedback resistor coupled between the input node and the output node of the receiver for controlling the gain of the receiver; and an impedance element coupled to the input node of the receiver for modifying the input impedance of the system and having an impedance value selected for filtering noise from the electrical signal and increasing the signal-to-noise ratio at the input node of the receiver so that the amplified electrical signal output by the receiver has a high signal-to-noise ratio for use in creating the control signal for optical wavelength stabilization.