Fig. 3: Ferroelectric nematic liquid crystals (FN-LC) alignment.
a Polarization-originated leakage current in response to an external electric field (Ealign ∝ Valign/[2 × df−c] = 2/(2 × 0.1) Vμm−1). A static power of Pstat ≈0.5 nA × 2 V is then expected to maintain the complete alignment. b Optical output (Pout) versus increasing Ealign. The polarity of Valign is reversed at tset. Despite the random changes in Pout at the beginning, we figured a settlement time of tset ≈ 100 s would be adequate to let dipole orientation relax and Pout to saturate to specific values associated with achieved molecular order. Pout sampled at tset is ≈2~3 dB bigger once complete alignment is achieved. Therefore, insertion loss (IL) is reduced in FN-LC compared to its unaligned state (i.e., before applying any voltage). c A microscopic image of the MZM along with the dipolar order of FN-LC in a section of its finger-loaded strip (FLS) waveguide in the cases of Ealign ≠ 0 and Ealign = 0 (other possibilities for dipolar order could exist, since we don’t know what the ground state is with this topology). A physical path length difference of ΔL ≈ 100 μm is incorporated in the upper arm. d Optical output spectrum (normalized versus grating coupler loss) versus applied voltage exhibiting changes in the electro-optic phase shifter (EOPS) complex refractive index (n + iκ, where △n ≫ △κ for an ideal EOPS) to make a full π shift enabled by the molecular orientation. The data is summarized in Table 2. A free spectral range (FSR) of ≈6.6 nm is observed.
