Thank you , it is working finally, I put 26ohm resistors instead of 100ohm.
The pics are communicating to each other, but the main slave device, don't.
It doe not have enough power ! The slave device is powered by the master device with 5v and it drains about 500mA. Pic1 inside the slave device is satisfied with 3v but the main device don't ... hmmmm .... what can I do in this situation ?