METHOD FOR STABILIZING THE AVALANCHE PHOTODIODE MODE Russian patent published in 2022 - IPC G01R19/175 H01L31/107 

FIELD: optical technology.

SUBSTANCE: invention relates to the reception of optical signals, in particular to the technique of receiving signals using avalanche photodiodes, and can be used in location, communication and other photoelectronic systems. The method for receiving optical signals using an avalanche photodiode includes threshold signal processing and the formation of output pulses using a threshold device when the signal from the output of the photodiode exceeds the specified threshold of operation. The offset voltage U_off of the photodiode is preliminarily set at a level U_off = U_off1, at which the minimum duration of microplasma pulses t_min exceeds the permissible maximum pulse repetition period T_max. Then the offset voltage is reduced to the level of U_off = U_offopt, at which the signal-to-noise ratio η = M_opt /σ_n is maximum, where M is the avalanche multiplication coefficient, σ_n is the RMS noise value. Signals start coming, and the switching time T_sw from the level of U_off1 to the level of U_offopt corresponds to the condition T_sw ≤ t_min - t_work, where t_min is the minimum duration of the microplasma pulse at the offset voltage of U_offopt, t_work is the duration of the working period of receiving signals. The optimal avalanche multiplication coefficient can be set in accordance with the dependence where is the square of the non-multipliable noise current; the square of the noise current of the preamplifier; e - the electron charge; I_s0 the constant component of the total current of microplasmas; Δ_f the bandwidth of the receiving path; the square of the multiplied noise current; I₁ =I_d is the primary (not multiplied) dark current of the photodiode; α a constant coefficient determined by the material and structure of the photodiode. The trigger threshold can be set using noise automatic adjustment.

EFFECT: ensuring the achievement of maximum sensitivity in all operating conditions, taking into account microplasma breakdowns and normal noise with a minimum time to reach the optimal avalanche mode.

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