Passive mode-locking and generation of ultrashort pulses in electron oscillators with saturable absorber in the feedback loop

A periodic train of powerful ultrashort microwave pulses can be generated in a two-section electron oscillators consisting of an amplifier and a saturable absorber installed in the feedback loop. This method of pulse formation is similar to the passive mode-locking effect well-known in the laser physics. In the electronic scheme, the wide class of amplifiers can be used including gyro-TWTs with an interaction space in the form of a multi-fold helically corrugated waveguide. As a saturable absorber we suggest to use the similar section in which the regime of Kompfner dip is realized by proper matching of parameters. It was experimentally demonstrated with using of a microwave magnetron as a source of the input signal.