Demonstration of a flexible electro-optic polymer modulator with a low half-wave voltage for ECG signals acquisition

Polymer-based electro-optic (EO) modulators have the advantages of low half-wave voltages and a low-cost preparation process and thus have extensive application prospects. A flexible, low half-wave voltage SU-8 Mach–Zehnder (M-Z) EO polymer modulator was proposed for human electrocardiogram (ECG) signal detection; polydimethylsiloxane (PDMS) was used as the substrate, and crosslinked polymer disperse red 1 (DR1)/SU-8 was used as the waveguide core layer. PDMS surface modification and SU-8 polarization were achieved, and the device was prepared by spin coating, ultraviolet (UV) lithography, wet etching and low-temperature sputtering. The experimental results show that the modulator initially operates in a linear operating regime under unbiased voltage conditions, and direct linear modulation of the voltage can be realized. After the preparation process, the low half-wave voltage was measured to be 2 V with a core size of 4000 μm×22000 μm, and the loss of the device was −2.1 dB.