The mechanism of the hydrogen bomb is based on

Fusion of deutrium and tritium

Hydrogen bomb is based on nuclear fusion. A large amount of nuclear energy is released by fusion of two light elements (elements with low atomic numbers). In a hydrogen bomb, two isotopes of hydrogen, deuterium(1 proton, 1 neutron) and tritium(1 proton, 2 neutron) are fused to form a nucleus of helium and a neutron.