Range-switching optical receiver with high sensitivity and wide dynamic range
AssigneeOrtel Corporation
InventorBryon L. Kasper
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Abstract
At least two innovations are used to overcome the limitations of conventional transimpedance or high impedance optical receiver front end amplifiers. The innovations are a) multiple stage equalization of a high-feedback resistor, low-gain transimpedance amplifier to obtain high sensitivity, and b) range switching of feedback resistors and equalization capacitors to obtain high overload. With these approaches, it is possible to design an optical receiver operating at the intrinsic limits of available device technology.
Claims28
An optical receiver comprising:
- a photodiode for receiving an optical input signal;
- a transimpedance amplifier coupled to the photodiode, wherein said transimpedance amplifier includes one or more feedback resistors;
- a plurality of equalization stages coupled to the transimpedance amplifier, wherein each of the plurality of equalization stages includes one or more equalization capacitors;
- and
- means for range switching between said one or more feedback resistors to control loop gain of said transimpedance amplifier and between said one or more equalization capacitors of each of said equalization stages to provide pole zero matching from stage to stage.
A method for amplifying a received optical signal over a broad bandwidth and wide dynamic range comprising:
- detecting characteristic of the received optical signal;
- adjusting a feedback resistance of a transimpedance amplifier and an equalization capacitance of each of a plurality of equalization stages in accordance with said detected characteristic;
- amplifying said received optical signal with said transimpedance amplifier;
- equalizing said amplified received signal with said plurality of equalization stages.
An optical receiver comprising:
- a photodiode for receiving an optical input signal;
- a transimpedance amplifier coupled to the photodiode, wherein said transimpedance amplifier comprises a plurality of feedback resistors;
- one or more feedback micro-switches for range switching between the plurality of feedback resistors;
- a plurality of equalization stages coupled to output of the transimpedance amplifier to extend bandwidth of the receiver;
- and
- one or more equalization micro-switches for range switching each equalization stage to provide pole-zero matching between said plurality of equalization stages.
An optical receiver, comprising:
- a photodiode for receiving an optical input signal;
- a transimpedance amplifier coupled to the photodiode, wherein said transimpedance amplifier comprises a plurality of feedback resistors;
- a plurality of equalization stages coupled to the transimpedance amplifier, wherein each of the plurality of equalization stages includes one or more equalization capacitors;
- programmable selection logic for selecting between said one or more feedback resistors and said one or more equalization capacitors in each of said equalization stages.
Dependencies are inferred from the claim text.