Design of ultra broadband transimpedance amplifiers (TIA) for optical fiber communications is disclosed. In one embodiment, a TIA comprises a g.sub.m-boosted dual-feedback common-base stage, a level shifter and an RC-degenerated common-emitter stage, and a first emitter-follower stage, wherein the first emitter follower stage is inductively degenerated. An output of the TIA is buffered using a second emitter-follower stage.

A method and circuit are provided for implementing enhanced CMOS inverter based optical Transimpedance Amplifiers (TIAs). A transimpedence amplifier (TIA) includes a photo-detector, and the TIA is formed by a first TIA inverter and a second TIA inverter. The first TIA inverter has an input from a cathode side of the photo-detector and the second inverter has an input from an anode side of the photo-detector. A replica TIA is formed by two replica inverters, coupled to a respective input to a first operational amplifier and a second operational amplifier. The first operational amplifier and the second operational amplifier have a feedback configuration for respectively regulating a set voltage level at the cathode side of the photo-detector input of the first inverter and at the anode side of the photo-detector input of the second inverter.

An isolation circuit and a method for providing isolation between two dies are provided. The isolation circuit includes: an isolation module, configured to generate an isolation signal based on an input signal from a first die and to provide isolation between the first die and a second die, where the isolation signal is smaller than the input signal in amplitude, and the first die is coupled with the second die; a latch module, configured to latch the isolation signal at a certain level and output a latched signal; an amplifier module, configured to amplify the latched signal. In the isolation circuit, a modulation module and a demodulation module can be saved.

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.

An electronic circuit includes an isolation amplifier, having a first input terminal receiving an AC-signal and including a linear opto-isolator. The opto-isolator has a first output terminal that provides a unipolar signal having an AC-component proportional to the input signal. The circuit includes a transimpedance receiver with first and second operational amplifiers. The first amplifier has a second output terminal and first and second differential input terminals, with the first differential input terminal receiving and amplifying the unipolar output signal from the first output terminal providing an output signal from the circuit at the second output terminal. The second amplifier is configured as an integrator, having a third output terminal coupled to the second differential input terminal and having third and fourth differential input terminals, with the third differential input terminal receiving the output signal from the second output terminal and the fourth differential input terminal connected to ground.

An input protection circuit (110) for an optocoupler (20) is provided. The input protection circuit (110) includes a first voltage limiter (D1) with a first terminal that is electrically coupled to an input terminal of an amplifier circuit (120), wherein the input terminal of the amplifier circuit (120) is configured to receive a PWM signal and the amplifier circuit (120) is configured to provide a voltage to the optocoupler (20).

A signal detection device according to one aspect of the present invention includes a receiver configured to receive a signal including at least a first signal component modulated by a first frequency and a second signal component modulated by a second frequency, and a detector configured to generate, using a base signal, a first reference signal to be used for detecting the first signal component and a second reference signal to be used for detecting the second signal component, perform lock-in detection on the signal received by the receiver using the first reference signal to obtain a first detection signal, perform lock-in detection on the signal received by the receiver using the second reference signal to obtain two second detection signals having different phases from each other, and change at least one of a frequency and a phase of each of the first and second reference signals to set one of the two second detection signals to zero.

A light-emitting unit outputs an optical signal corresponding to an input electric signal. A light-receiving unit is electrically insulated from the light-emitting unit and outputs an electric signal according to the received optical signal as an output signal. In the light-receiving unit, a first light-receiving device outputs an optical current according to the optical signal. A second light-receiving device is provided not to receive the optical signal. A current duplication circuit duplicates a current flowing through the second light-receiving device. A current-voltage conversion circuit converts a current, which is generated by subtracting the current duplicated by the current duplication circuit from a current flowing through the first light-receiving device, into a voltage signal. A comparator output a result of a comparison between the voltage signal converted by the current-voltage conversion circuit and a threshold voltage as the output 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 TIA converts a current signal received at its terminal to a voltage signal. The TIA includes an amplifier that includes an input node connected to the terminal and that converts a current signal received at the input node to a voltage signal; a first diode whose cathode is connected to the terminal; a second diode whose anode is connected to the terminal; a first current source connected to an anode of the first diode, the first current source supplying a first forward current to the first diode; a second current source connected to a cathode of the second diode, the second current source supplying a second forward current to the second diode; and a controller that controls forward currents respectively generated by the first current source and the second current source in accordance with an increase and decrease in the voltage signal.