Integrable thin-film Fabry-Pérot type electro-optic modulator

Abstract

We report on an integrable thin-film Fabry-Pérot type electro-optic modulator (EOM) centered around an electro-optically active so-called guest-host polymer. This polymer material contains novel synthesized chromophore molecules (C3), which are aligned by electro-poling inside an amorphous polycarbonate host-matrix. When integrated into our Fabry-Pérot cavity, the electro-optic activity of the poled material can be observed in the short wavelength near infrared spectral range (approximately 900 nm -1070 nm). We derived a value of ~220 pm/V for its linear electro-optic coefficient at 988 nm from spectral transmission measurements with increasing direct voltages applied to the EOM. The resulting half-wave voltagelength product of the EOM setup is 0.25 Vcm. As an exemplary functional test, we demonstrated an intensity modulation of a 974 nm diode laser by applying ± 11.5 V alternating voltage to the EOM. Due to the all thin-film realization of the EOM setup, it is compatible to the substrate free, miniaturized interference filter fabrication method. With this method, thin-film elements with edge lengths between 25 µm and 2 mm can be fabricated. In combination with the demonstrated low drive voltage, these compact EOM filters are excellent candidates for hybrid integration into photonic platforms, as shown in this contribution.