Improved dither detection, measurement, and voltage bias adjustments for an electro-optical modulator are described. The electro-optical modulator generally includes RF electrodes and phase heaters interfaced with semi-conductor waveguides on the arms of Mach-Zehnder interferometers, where a processor is connected to output a bias tuning voltage to the electro-optical modulator for controlling optical modulation. A variable gain amplifier (VGA) can be configured with AC coupling connected to receive a signal from a transimpediance amplifier (TIA) that is configured to amply a photodetector signal from an optical tap that is used to measure an optical signal with a dither signal. The analog to digital converter (ADC) can be connected to receive output from the VGA. The processor can be connected to receive the signal from the ADC and to output the bias tuning voltage based on evaluation of the signal from the tap.

In conventional optical receivers the dynamic range is obtained by using variable gain amplifiers (VGA) with a fixed trans-impedance amplifier (TIA) gain. To overcome the SNR problems inherent in conventional receivers an improved optical receiver comprises an automatic gain control loop for generating at least one gain control signal for controlling gain of both the VGA and the TIA. Ideally, both the resistance and the gain of the TIA are controlled by a gain control signal.

Methods and systems for process and temperature compensation in a transimpedance amplifier using a dual replica and configurable impedances is disclosed and may include a transimpedance amplifier (TIA) circuit comprising a first TIA, a second TIA, a third TIA, and a control loop. The first TIA comprises a fixed feedback resistance and the second and third TIAs each comprise a configurable feedback impedance. The system may comprise a gain stage with inputs coupled to outputs of the first and second TIAs and with an output coupled to the configurable feedback impedance of the second and third TIAs. The circuit may be operable to configure a gain level of the first TIA based on the fixed feedback resistance and a reference current applied at an input to the first TIA, and configure a gain level of the second and third TIAs based on a control voltage generated by the gain stage.

In conventional optical receivers the dynamic range is obtained by using variable gain amplifiers (VGA) with a fixed trans-impedance amplifier (TIA) gain. To overcome the SNR problems inherent in conventional receivers an improved optical receiver comprises an automatic gain control loop for generating at least one gain control signal for controlling gain of both the VGA and the TIA. Ideally, both the resistance and the gain of the TIA are controlled by a gain control signal.

Methods and systems for a distributed optoelectronic receiver are disclosed and may include an optoelectronic receiver having a grating coupler, a splitter, a plurality of photodiodes, and a plurality of transimpedance amplifiers (TIAs). The receiver receives a modulated optical signal utilizing the grating coupler, splits the received signal into a plurality of optical signals, generates a plurality of electrical signals from the plurality of optical signals utilizing the plurality of photodiodes, communicates the plurality of electrical signals to the plurality of TIAs, amplifies the plurality of electrical signals utilizing the plurality of TIAs, and generates an output electrical signal from coupled outputs of the plurality of TIAs. Each TIA may be configured to amplify signals in a different frequency range. One of the plurality of electrical signals may be DC coupled to a low frequency TIA of the plurality of TIAs.

A frequency modulated continuous wave (FMCW) light detection and ranging (LIDAR) system includes an automatic gain control (AGC) unit to reduce the dynamic range of the signal to be processed. The system detects a return beam of a light signal transmitted to a target, having a first dynamic range in a time domain. The AGC unit can measure a power of the return beam, and apply variable gain in the time domain to reduce a dynamic range of the return beam to a lower dynamic. An analog to digital converter (ADC) generates a digital signal based on the return beam. A processor can perform time domain processing on the digital signal, convert the digital signal from the time domain to a frequency domain, and perform frequency domain processing on the digital signal in the frequency domain.

A device for converting a photonic signal to be analyzed includes two output branches, and one input for receiving a photonic signal to be analyzed and splitting off a part of the photonic signal to each output branch. The device imposes a phase shift of approximately 180 degrees between the two parts, each output branch including a photodiode generating a respective first electrical current. Each output branch generates a second electrical current according to a value of the first current of the branch considered. The device also includes an amplifier generating an output signal according to a difference between the values of the second currents, a gain being defined for each output branch, and at least one electronically controlled adjustment element configured to modify one of the gains.

The invention relates to a device for converting a photonic signal to be analyzed, comprising two output branches, one input for receiving a photonic signal to be analyzed and splitting off a part of the photonic signal to each output branch, the device imposing a phase shift of approximately 180 degrees between the two parts, each output branch including a photodiode generating a respective first electrical current, each output branch generating a second current according to a value of the first current of the branch considered, the device comprising an amplifier generating an output signal according to a difference between the values of the second currents, a gain being defined for each output branch, the device including at least one electronically controlled adjustment element apt to modify one of the gains.

An optical module includes an optical receiver with a complementary metal-oxide semiconductor (CMOS) transimpedance amplifier (TIA) and a digital signal processing (DSP) circuit. The DSP circuit is integrated with the CMOS TIA and facilitates adaptability of the CMOS TIA, and the CMOS TIA can adapt by using information provided by the DSP circuit.

Aspects of this disclosure relate to a receiver for a light detection and ranging system. The receiver includes a transimpedance amplifier that is operable in a linear mode for a range of power of light received by the receiver. The receiver can provide information about amplitude of the light outside of the range of power of the light for which the transimpedance amplifier operates in the linear mode. This information can be useful, for example, in identifying an object from which light received by the receiver was reflected.