Fig. 1. (a) Schematic configuration of the proposed ultracompact and high-speed EO modulator using a new 2×2 FP cavity on an LNOI platform; top views of (b) a mode (de)multiplexer and (c) an AMWG.

Fig. 2. (a) Calculated transmissions from the TE1 and TE0 modes of waveguide A; (b) simulated light propagation when the TE1 and TE0 modes are launched from the right side of the dual-core adiabatic taper (at 1550 nm); (c) calculated transmission (T) and reflection (R) of the AMWG when the TE0 mode is launched; (d) simulated light propagation in the designed AMWG for wavelengths of 1550 nm and 1600 nm, respectively.

Fig. 3. (a) The optical microscope image of the fabricated FP cavity modulator based on AMWGs; the SEM images of (b) the dual-core taper of mode (de)multiplexer, (c) the modulation region, and (d) the AMWG.

Fig. 4. Measured transmissions (a) T13/T14 and (b) T23/T24 of the fabricated modulator; measured transmissions (c) T13 and (d) T14 when applying different voltages of −20, −10, 0, 10, and 20 V.

Fig. 5. Measured small-signal EO response (S21) of the fabricated EO modulator for the transmissions (a) T13 and (b) T14.

Fig. 6. Measured eye diagrams for the OOK signal at the data rate of 40 Gbps and the PAM4 signal at the data rate of 80 Gbps for the transmissions (a) T13 and (b) T14.