An optical resonator, a photonic system and a method of optical resonance employ optical waveguide segments connected together with total internal reflection (TIR) mirrors to form a closed loop. The optical resonator includes the optical waveguide segments, the TIR mirrors and a photo-tunneling input/output (I/O) port. The photo-tunneling I/O port includes one of the TIR mirrors. The method includes propagating and reflecting an optical signal, or a portion thereof, in the optical resonator, and transmitting a portion of the optical signal through the photo-tunneling I/O port. The photonic system includes the optical resonator and a source of an optical signal.