The invention relates to a single-mode half microdisk
resonant cavity which comprises a closed inner
contour line and a closed outer
contour line. A
waveguide (3) is arranged between the inner
contour line and the outer contour line. The inner contour line is composed of sector connecting areas (2) used for being in
electrical connection or mechanical connection and a transition curve (1) which achieves the purpose that the
waveguide width is gradually changed from narrow to wide, and the angle of each sector connecting area (2) is smaller than or equal to 270 degrees and larger than zero degree. Each connecting area (2) maximally allows a connecting structure within the range of 270 degrees, so that connecting resistance is small, and high-speed
resonance can be achieved. The transition curve (1) can guarantee the fact that a high order mode and a leakage mode are not excited while enabling the
waveguide of the
resonant cavity to be gradually widened, and
cavity loss is lowered. The half microdisk
resonant cavity is in a single-mode work mode, the range of free spectrum can not be reduced, the strict demand for a
light field mode of application such as filtering and modulation can be met, the half microdisk resonant cavity has multiple potential purposes in an integrated field and comprises a low
energy consumption and high speed electrooptical modulator, an
optical logic operation device, an
active power filter, a heating / tuning unit, a thermo-optic switch, an electrical / mechanical / optical
transducer and the like which need electrical or mechanical connection.