p-Phenylenevinylene-2,5-diethylhexyloxy-p-phenylenevinylene and m-phenylenevinylene-2,5-diethylhexyloxy-p-phenylenevinylene homopolymers (3 and 4) have been prepared by the ring-opening metathesis polymerization (ROMP) of strained cyclophanedienes, initiated by the second generation Grubbs catalyst. The as-formed polymers have a backbone of alternating cis- and trans-vinylene linkages due to the opening of only one vinylene of the cyclophanediene. Irradiation with UV light results in an isomerization to an all-trans-vinylene microstructure for all polymers. The polymer chain ends remain active after complete consumption of the cyclophanediene, and block copolymers can be prepared by addition of further cyclophanediene. The optical and electronic properties of the homopolymers and block copolymers are reported.
Excellent control in the synthesis of MEH-PPV can be achieved by microwave assisted, ring-opening metathesis polymerisation (ROMP) of [2.2]paracyclophanedienes.
To reduce the ever-increasing energy consumption in datacenters, one of the effective approaches is to increase the ambient temperature, thus lowering the energy consumed in the cooling systems. However, this entails more stringent requirements for the reliability and durability of the optoelectronic components. Herein, we fabricate and demonstrate silicon-polymer hybrid modulators which support ultra-fast single-lane data rates up to 200 gigabits per second, and meanwhile feature excellent reliability with an exceptional signal fidelity retained at extremely-high ambient temperatures up to 110 °C and even after long-term exposure to high temperatures. This is achieved by taking advantage of the high electro-optic (EO) activities (in-device n3r33 = 1021 pm V−1), low dielectric constant, low propagation loss (α, 0.22 dB mm−1), and ultra-high glass transition temperature (Tg, 172 °C) of the developed side-chain EO polymers. The presented modulator simultaneously fulfils the requirements of bandwidth, EO efficiency, and thermal stability for EO modulators. It could provide ultra-fast and reliable interconnects for energy-hungry and harsh-environment applications such as datacentres, 5G/B5G, autonomous driving, and aviation systems, effectively addressing the energy consumption issue for the next-generation optical communication.
We propose a high efficiency apodized grating coupler with a bottom reflector for silicon nitride photonic integrated circuits. The reflector consists of a stack of alternate silicon nitride and silicon dioxide quarter-wave films. The design, fabrication and optical characterization of the couplers has been presented. The measured fiber to detector insertion loss was −3.5 dB which corresponds to a peak coupling efficiency of −1.75 dB. A 3 dB wavelength bandwidth of 76.34 nm was demonstrated for the grating coupler with a 20-layer reflector. The fabrication process is CMOS-compatible and requires only a single etching step.
In this work, we have demonstrated
a hybrid TiO2–Si3N4 ring resonator
with a high-Q and a temperature-insensitive resonance. The waveguide
consists of a thermo-optic positive Si3N4 slab
and a negative TiO2 overcladding. The TiO2 layer
has a shallow ridge structure, which has been designed to realize
an athermal operation and maintain a low scattering loss. During the
fabrication of this waveguide, there was no need to utilize the dry-etching
process. The method affords a straightforward fabrication and a precise
control over the waveguide dimensions. As a result, the ring resonator
exhibits a high Q value of 1.55 × 105, a low propagation
loss of 0.4 dB/cm, and a small temperature-dependent wavelength shift
of 0.14 pm/°C between 25 and 60 °C.
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