Аннотация:In this paper, we present the research of the blinding attack on single photon avalanche diodes (SPAD) based on InGaAs structure which is used in quantum key distribution systems with modulated laser radiation. One of the variants of this attack is using continuous wave (CW) light but there is protection from it like monitoring of SPAD’s current. Thus, we use modulated CW radiations. Modulation allows us to establish parameters of blinding pulses. We studied the dependencies of the detector’s bias current on blinding pulse energy using different widths of light pulses in the range from 4ns to 20 ns than we applied various repetition rates which are 10 MHz, 5 MHz, 2.5 MHz, and 1MHz. Even we investigate this dependence using the not rectangular shape of pulses on repetition rates mentioned above.