Frequency Response of Thermo-Optic Phase Modulators Based on Fluorinated Polyimide Polymer Waveguide

Abstract

Polymer waveguide phase modulators exhibit stable low-power phase modulation owing to their exceptional thermal confinement and high thermo-optic effect, and thus, have the merit of thermal isolation between channels, which is crucial for an optical phased array (OPA) beam scanner device. In this work, a waveguide phase modulator was designed and fabricated based on a high-refractive-index fluorinated polyimide. The propagation loss of the polyimide waveguide and the temporal response of the phase modulator were characterized. Moreover, the transfer function of the phase modulator including multiple poles and zeros was obtained from the measured frequency response. The polyimide waveguide modulator device demonstrated a fast response time of 117 μs for 1 kHz input signal, however, for 1 mHz step-function input, it exhibited an additional 5% phase change in 5 s.

Human Enamel Fluorination Enhancement by Photodynamic Laser Treatment

“…In fact, the absorption bands reported in Figure 6 b demonstrate a low resolution level of the phosphate peak for simple fluorinated enamel. On the other side, the obtained FT-IR bands for the enamel treated by fluorination showed the presence of a peak at 3573 cm −1 , which belongs to the hydroxyl groups’ substitution with the fluoride ions in the hydroxyapatite structure, in good agreement with the literature [ 34 ]; this peak is visible in Figure 6 b.Such a complex interaction of fluoride ions has been observed for several dental materials, such as fluorinated methacrylate [ 35 ], fluorinated polyimide [ 36 ], and low-fluorinated oligoamides [ 37 ]. The photodynamic laser treatment effect on the enamel samples ( Figure 6 c) did not cause the appearance of new bands or the disappearance of some bands, in good agreement with the data in literature evaluating other laser wavelengths on dental tissues [ 38 , 39 , 40 , 41 ].…”

Efficient Line Beam Scanning Based on a Hybrid Optical Phased Array Rendering Flexible Field-of-Views

“…The electrical power consumed to attain a π-phase shift was calculated to be as low as P π = 2.1 mW, signifying the excellent TO property and thermal confinement of the adopted polymers which had thermal conductivity and TO coefficient of 0.2 W/mK and −2.5 × 10 −4 /°C, respectively. The interferometer was deployed to investigate the power consumption of phase modulators experimentally, where the P π was measured to be ∼2.3 mW [26], [27], [28], [29].…”

Polymeric integrated optic current sensors based on polarization rotated reflection interferometry

“…The 3 dB directional coupler was designed by designing a waveguide with effective index method that satisfies single mode and determining the length of the coupling region through BPM simulation [13]. The thermo-optic phase modulator was designed to prevent thermal crosstalk between adjacent waveguides through thermal flow simulation [14]. The TE-pass polarizer was designed using the effective index calculation [11].…”