This optical communication device (1) is provided with: a plurality of light-receiving elements (11) configured to receive communication light, the plurality of light-receiving elements being provided so as to correspond to a plurality of channels; and a controller (15) configured to perform control to invalidate output from a light-receiving element that has received high-intensity light higher in light intensity than a predetermined value among the plurality of light-receiving elements.

In optical receivers, cancelling the DC component of the incoming current is a key to increasing the receiver's effectiveness, and therefore increase the channel capacity. Ideally, the receiver includes a DC cancellation circuit for removing the DC component; however, in differential receivers an offset may be created between the output voltage components caused by the various amplifiers. Accordingly, an offset cancellation circuit is required to determine the offset and to modify the DC cancellation circuit accordingly.

The present disclosure relates to optical receivers. One example optical receiver includes an optoelectronic detector, a transimpedance amplification (TIA) circuit, a single-ended-to-differential converter, an I/O interface, and a controller. The optoelectronic detector, having bandwidth lower than required system transmission bandwidth, converts an optical signal into a current signal. The TIA circuit compensates gain for the received current signal based on a received control signal to obtain a voltage signal, where a frequency response value of the current signal within first bandwidth is greater than that within the bandwidth of the optoelectronic detector, and any frequency in the first bandwidth is not lower than an upper cut-off frequency of the optoelectronic detector. The single-ended-to-differential converter converts the voltage signal into a differential voltage signal. The I/O interface outputs the differential voltage signal. The controller generates the control signal based on the differential voltage signal.

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.

This invention relates to a optical receiver circuit (200) comprising: at least one photo detector (207) configured to convert a received light signal to an input current signal, a transimpedance amplifier circuit (201) with an input to receive the input current signal from the at least one photo detector (207) and being configured to convert the received input current signal to an output voltage signal to generate an output signal of the transimpedance amplifier circuit (201), wherein the transimpedance amplifier circuit comprises a plurality of gain amplifier stages (209, 210, 211), a DC restoration component (205), wherein the DC restoration component (205) is configured to receive the output voltage signal of the transimpedance amplifier circuit (201) for restoring the DC component of the received current signal and configured for outputting a corresponding current signal, and an automatic gain control component (204) configured for controlling via at least one programmable feedback resistor (226, 227) the equivalent transimpedance of the transimpedance amplifier circuit based on the signal output by the DC restoration component (205) to provide a constant output voltage amplitude for different current ranges of the input current signal.

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 waveguide delay based equalization summing at single-ended to differential converters in optical communication are disclosed and may include: in an optoelectronic receiver including a directional coupler, photodetectors, transimpedance amplifiers (TIAs), and a gain stage, receiving an input optical signal; splitting the input optical signal into first and second optical signals using the directional coupler; generating a first current from the first optical signal using a first photodetector; generating a first voltage from the first current using a first TIA; communicating the first voltage to a first input of the gain stage; generating a second current from the second optical signal using a second photodetector; generating a second voltage from the first signal using a second TIA; communicating the second voltage to a second input of the gain stage; and generating a differential output voltage from the first and second voltages using the gain stage.

One example of a receiver includes a first stage, a second stage, a third stage, and an automatic gain controller. The first stage amplifies an input signal to provide a first signal. The second stage amplifies or attenuates the first signal to provide a second signal based on a tunable gain of the second stage. The tunable gain is adjusted in response to a differential signal. The third stage amplifies the second signal to provide an output signal. The automatic gain controller provides the differential signal based on a comparison between a peak voltage of the output signal and the sum of a common mode voltage of the output signal and an offset voltage.

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.

An apparatus is described which uses directly modulated InGaN Light-Emitting Diodes (LEDs) or InGaN lasers as the transmitters for an underwater data-communication device. The receiver uses automatic gain control to facilitate performance of the apparatus over a wide-range of distances and water turbidities.