Abstract:Mach-Zehnder modulators fabricated by gallium diffusion in y-cut lithium niobate (LiNbO 3 ) are presented. The measured halfwave voltages are 6.2 and 3.2 V when the electrode lengths are 0.4 and 0.8 cm, respectively. By calculating the overlap integral between the modulating electric and the guided optical fields, the value of the electrooptic coefficient r 33 is found in good agreement with that of the bulk LiNbO 3 , which indicates no significant degradation in r 33 is induced by the in-diffused gallium atom… Show more
“…Applying the same lithography and lift-off steps, 100 nm thick Ti electrodes were deposited on both sides of the TiO 2 waveguide. The ToL fabrication avoided delicate and costly processes including ion slicing and wafer bonding utilized in prior LN thin film devices 20,21 .Figure 1( a ) Schematic of the ToL waveguide fabrication process. The waveguide structure was defined by photoresist (PR) on the LN substrate through photolithography, following TiO 2 thin film deposition by reactive RF sputtering.…”
Tunable photonic circuits were demonstrated in the mid-Infrared (mid-IR) regime using integrated TiO2-on-LiNbO3 (ToL) waveguides. The upper waveguide ridge was made by a sputtered TiO2 thin film with broad transparency at λ = 0.4–8 µm and an optimized refractive index n = 2.39. The waveguide substrate is a z-cut single crystalline LiNbO3 (LN) wafer that has strong Pockels effect, thus enabling the tunability of the device through electro-optical (E-O) modulation. A sharp waveguide mode was obtained at λ = 2.5 µm without scattering or mode distortion found. The measured E-O coefficient γeff was 5.9 pm/V approaching γ31 of 8.6 pm/V of LN. The ToL waveguide showed a hybrid mode profile where its optical field can be modified by adjusting the TiO2 ridge height. Our monolithically integrated ToL modulator is an efficient and small footprint optical switch critical for the development of reconfigurable photonic chips.
“…Applying the same lithography and lift-off steps, 100 nm thick Ti electrodes were deposited on both sides of the TiO 2 waveguide. The ToL fabrication avoided delicate and costly processes including ion slicing and wafer bonding utilized in prior LN thin film devices 20,21 .Figure 1( a ) Schematic of the ToL waveguide fabrication process. The waveguide structure was defined by photoresist (PR) on the LN substrate through photolithography, following TiO 2 thin film deposition by reactive RF sputtering.…”
Tunable photonic circuits were demonstrated in the mid-Infrared (mid-IR) regime using integrated TiO2-on-LiNbO3 (ToL) waveguides. The upper waveguide ridge was made by a sputtered TiO2 thin film with broad transparency at λ = 0.4–8 µm and an optimized refractive index n = 2.39. The waveguide substrate is a z-cut single crystalline LiNbO3 (LN) wafer that has strong Pockels effect, thus enabling the tunability of the device through electro-optical (E-O) modulation. A sharp waveguide mode was obtained at λ = 2.5 µm without scattering or mode distortion found. The measured E-O coefficient γeff was 5.9 pm/V approaching γ31 of 8.6 pm/V of LN. The ToL waveguide showed a hybrid mode profile where its optical field can be modified by adjusting the TiO2 ridge height. Our monolithically integrated ToL modulator is an efficient and small footprint optical switch critical for the development of reconfigurable photonic chips.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
