Optical receiver with wide dynamic range transimpedance amplifier
AssigneeFinisar Corporation
InventorsGilles P. Denoyer, Dan Case
Life of this patent
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Abstract
An optical component, such as an optical receiver, is provided that includes a detector configured to receive a signal from an optical fiber and to communicate with a translationl module of the optical component. A transimpedance amplifier of the optical component is configured to receive an electrical signal from the detector and to transmit an amplified signal to the translation module. The transimpedance amplifier is configured for a controlled low cutoff frequency as optical power to the transimpedance amplifier increases, so that the optical sensitivity of the transimpedance amplifier is not traded for optical overload.
Claims33
An optoelectronic component, comprising:
- a detector configured to receive an optical signal;
- and
- a transimpedance amplifier having a controlled low cutoff frequency as optical power to the detector increases, and the transimpedance amplifier comprising:
- a forward transimpedance circuit configured to receive an input current from the detector;
- and
- a feedback circuit that includes:
- a first circuit configured to detect a low frequency component of the output signal;
- and
- a second circuit configured to be driven by the low frequency component of the output signal and connected with the forward transimpedance circuit such that a transconductance of the second circuit is substantially unrelated to a low frequency cutoff of the transimpedance amplifier as the input current increases.
An optical receiver, comprising:
- a detector configured to receive an optical signal;
- a translation module;
- and
- a transimpedance amplifier configured for communication with the detector and the translation module and having a controlled low cutoff frequency as optical power to the detector increases, and the transimpedance amplifier comprising:
- an input stage that receives an input current signal from the detector and generates an output voltage;
- a gain stage that amplifies the output voltage to generate an amplified signal;
- and
- a feedback circuit that includes:
- a low frequency circuit that detects a low frequency component of the amplified signal such that the low frequency component can be substantially removed from the input current signal;
- and
- variable impedance circuitry, wherein an impedance of the variable impedance circuitry is dependent on an average current of the input current signal such that an AC portion of the input current signal is attenuated as the average current increases and wherein a low cutoff frequency of the transimpedance amplifier approaches an upper limit as the average current increases.
In an optoelectronic component that receives optical signals of different optical powers, a method for controlling a low cutoff frequency as optical power of an optical signal changes, the method comprising:
- converting an optical signal to an input current;
- amplifying the input current to produce an output signal;
- detecting a low frequency component of the output signal, wherein the low frequency component corresponds to an impedance level of a variable impedance associated with the input current;
- and
- attenuating an AC component of the input current with the variable impedance by reducing an impedance level of the variable impedance as the input current increases in amplitude, wherein a low cutoff frequency is substantially independent of the transconductance of the variable impedance and wherein the low cutoff frequency approaches an upper limit as the amplitude of the input current increases.
Dependencies are inferred from the claim text.