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-devicen³r₃₃ = 1021 pm V⁻¹), low dielectric constant, low propagation loss (α, 0.22 dB mm⁻¹), and ultra-high glass transition temperature (T_g, 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.

High-quality silicon nitride (Si₃N₄) films with a low stress and optical loss were deposited at low temperature (150°C) using liquid source chemical vapor deposition (LSCVD). The refractive index of the Si₃N₄ film was optimized by changing the composition ratio and deposition temperature. An integrated photonic structure of micro-ring resonator based on the as-deposited Si₃N₄ layer has been demonstrated to exemplify its viability as a photonic integration platform. Bragg gratings are fabricated at both ends of the bus waveguide to improve coupling efficiency and testing flexibility. A measured waveguide loss of 2.9 dB/cm and a high Q-factor of 5.2 × 10⁴ are achieved. The LSCVD deposited Si₃N₄ is therefore a highly promising photonic integration platform for various integrated photonic applications.

The coupling intensity modulator based on a triple-microring structure was proposed and numerically investigated for a high speed and a low bit error ratio (BER) operation. The modulator consists of a dual-microring optical cavity and a gate-microring energy feedback path. The optical cavity ensures a high energy storing efficiency, and the feedback path enables modulation with little intracavity energy decay. The bandwidth of 103 GHz and modulation depth of 6.2 dB at 2.0 Vpp were theoretically verified by the analysis of the sinusoidal modulation performance. Pulse modulation resulted in a data rate of 160 Gbps, an extinction ratio of 16.84 dB, and a BER of 1 × 10⁻⁸. The proposed modulator is applicable for compact, high-speed, and low-energy photonic integration.