Electro‐optic polymer/titanium dioxide hybrid core ring resonator modulators

Abstract

Compact electro‐optic (EO) modulators are desirable for a number of applications. In this study, a ring modulator has been fabricated in the titanium dioxide (TiO2) core and EO polymer cladding waveguide structure. A 250‐nm thick TiO2 core was utilized to minimize the ring radius down to 100 μm, to avoid using the top cladding between the EO polymer and the electrode, and to improve the poling efficiency. The resonance obtained by the ring modulator was observed to shift by 0.02 nm/V due to the enhanced in‐device EO coefficient of 105 pm/V. A modulation depth of 3 dB was observed at the frequency response function at 20 kHz using 2‐V Vp–p clock signal.

Athermal Hybrid Silicon/Polymer Ring Resonator Electro-optic Modulator

“…where λ i is the one resonance peak wavelength and n eff is the effective refractive index change. 18 In the hybrid waveguide, Δλ i can be induced by the refractive index change of the EO polymer (Δn EO ), where the Δn EO is expressed by…”

“…where V is the applied voltage and d is the interelectrode distance. 18 By using eqs 2 and 3, the in-device EO coefficient (r 33 ) of the ring resonator modulator was calculated to be 48 pm/V. In order to further evaluate the athermal operation of the fabricated ring resonator, high-frequency measurements were made by applying an ac field at various temperatures.…”

“…The applied voltage ranged from −10 to 10 V with an interval of 5 V. After linear fitting the measured result, the resonance tunability Δλ i / V was found to be 6.1 pm/V, where Δλ i is the resonance peak shift and V is the applied dc voltage. In a ring resonator, the Δλ i is given by where λ i is the one resonance peak wavelength and n eff is the effective refractive index change . In the hybrid waveguide, Δλ i can be induced by the refractive index change of the EO polymer (Δ n EO ), where the Δ n EO is expressed by where V is the applied voltage and d is the interelectrode distance .…”

“…In a ring resonator, the Δλ i is given by where λ i is the one resonance peak wavelength and n eff is the effective refractive index change . In the hybrid waveguide, Δλ i can be induced by the refractive index change of the EO polymer (Δ n EO ), where the Δ n EO is expressed by where V is the applied voltage and d is the interelectrode distance . By using eqs and , the in-device EO coefficient ( r 33 ) of the ring resonator modulator was calculated to be 48 pm/V.…”