Large-dynamic-range athermal lithium niobite on insulator/ TiO2 nanobeam electric field sensor

An integrated optical electric field (E-field) sensor based on a one-dimensional photonic crystal nanobeam cavity on a lithium niobite on insulator (LNOI) platform is reported here. It has a large dynamic range and extreme sensitivity. The dielectric resonant mode has a quality factor Q 10(5). The waveguide-coupled structure, only 25 mu m long, is beneficial for future on-chip integration. The use of TiO2 compensates for the thermo-optical effect of lithium niobite (LN), while the high dielectric constant of TiO2 influences the E-field distribution. A tri-layer TiO2/LNOI/TiO2 nanobeam structure is proposed to improve electro-optical modulation efficiency in LN. Detailed analysis of noise sources shows the theoretical minimum detectable E-field to be 0.15 V m(-1) with a dynamic range of 83 dB. The temperature-induced resonant wavelength variation is within 3 pm degrees C-1 in the range of -40 degrees C to 40 degrees C.

Automated summary

An integrated optical electric field sensor based on LNOI platform with one-dimensional photonic crystal nanobeam cavity is reported, featuring extreme sensitivity and large dynamic range. The use of TiO2 to compensate for LN's thermal-optical effect and its high dielectric constant impacting E-field distribution is proposed. A tri-layer TiO2/LNOI/TiO2 nanobeam structure is suggested to enhance electro-optical modulation efficiency in LN.