A device for converting a photonic signal to be analyzed, comprising:
- a photonic-electric conversion element, and
- an electronic processing device,
- the conversion element including a splitter having two outputs connected to a first output branch and to a second output branch, respectively, the splitter including one or two inputs for receiving one or two input photonic signals, respectively, the splitter mixing the input photonic signals in a case where two inputs are present, the one received input photonic signal or the mixing of the two received photonic signals corresponding to a photonic signal to be analyzed, the splitter leading a first part of the photonic signal to be analyzed to the first output branch and leading a second part of the photonic signal to be analyzed to the second output branch, the conversion element being configured for imposing, via the splitter, a phase shift of approximately 180 degrees between the first and the second parts of the photonic signal to be analyzed, each of the first and second output branches including a waveguide portion and a photodiode,
- each photodiode being configured for generating a respective first electrical current in response to receiving the first or second part of the photonic signal to be analyzed,
- each output branch being configured for generating at the output, a second electrical current having a value equal to or a multiple of a value of the first electrical current of the output branch considered,
- the processing device comprising an amplifier configured for generating at least one output signal according to a difference between the values of the two second electrical currents,
- a gain being defined for each output branch, the gain being a coefficient of proportionality between the value of the second electrical current of the output branch considered and a photonic power of the first or second part of the photonic signal to be analyzed, received by the output branch,
- the conversion device including at least one electronically controlled adjustment element, configured to modify one of the gains, the processing device including a first regulation loop comprising a low-pass filter and a device for controlling each adjustment element, the regulation loop receiving the output signal from the amplifier and producing an electrical control signal for each adjustment element so as to regulate a mean value of each output signal to a predefined setpoint value corresponding to equalization of DC components of the values of the two second electrical currents,
- each photodiode has an anode and a cathode, at least one adjustment element being configured for modifying an electrical voltage between the anode and the cathode of the corresponding photodiode, and
- each photodiode having a quantum efficiency, the quantum efficiency of each photodiode being equal to a ratio between, in the numerator, a number of charge carriers generated per unit of time and, in the denominator, a number of photons illuminating the photodiode during a same unit of time, and at least one adjustment element being configured for modifying the quantum efficiency of a corresponding photodiode, the quantum efficiency of each photodiode being modified via modification of the electrical voltage between the anode and the cathode of the corresponding photodiode.