An adhesive-free encapsulation sapphire Fabry–Perot interferometer (FPI) is proposed and demonstrated for high-temperature pressure measurements. The sapphire FPI sensor is packaged by zirconia ferrules and a zirconia sleeve, which is easy to be configured and low in cost. Owing to this packaging technology, the sapphire FPI sensor presents good stability and high temperature resistance. The pressure and temperature properties of the sapphire FPI sensor are investigated within a temperature range from − 50 ∘ C to 1200°C and a pressure range from 0.4 to 4.0 MPa. Experimental results show the FPI has a temperature sensitivity of 23 pm/°C and still works as the temperature is up to 1200°C. Meanwhile, the wavelength shift of the sapphire FPI versus the applied pressure is linear at each tested temperature. The pressure sensitivity is measured to be 1.20 nm/MPa at 1200°C, and the linear response shows the proposed sensor has good repeatability within 0.4–4.0 MPa. Such a sapphire FPI sensor has potential applications in engineering areas, such as the oil industry and gas boilers.

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Semitransparent organic solar cells (ST‐OSCs) can be made in different colors, allowing light to pass through, and yet absorb enough visible and near‐infrared (NIR) light to generate electricity. However, it remains a challenge to achieve high performing ST‐OSCs over the two competing indexes of power conversion efficiency (PCE) and average visible transmittance (AVT). This work reports an effort to develop record‐performance ST‐OSCs using a low/high index optical coupling layer (OCL) and a 2D photonic‐structured antireflective (AR) coating. High‐throughput optical screening is used to improve the understanding of OCL structure−performance relationships and the predicting of NIR absorption enhancement for ST‐OSCs. The concurrent use of a low/high index Na3AlF6 (170 nm)/ZnS (110 nm) OCL, identified among about 200 thousand simulated device configurations and a 900 nm pitch‐sized 2D photonic‐structured AR coating, fabricated using nanoimprint lithography, enables the record‐performance ternary PM6:BTP‐eC9:L8‐BO‐based ST‐OSCs, achieving simultaneously a record‐high PCE of 15.2%, a high AVT of 32%, an impressive light utilization efficiency of 4.86%, and a favorable color‐rendering index of 82. The results of the ST‐OSCs demonstrated in this work provide an attractive option for a plethora of applications in self‐powered greenhouses and building‐integrated photovoltaic systems.

Integrating the graded index (GRIN) waveguide with the 2-D inversely-tapered waveguide, a new design of spot size converter (SSC) has been proposed to couple the light beam between the cleaved single-mode fiber (SMF) and the silicon (Si) wire waveguide on the silicon-on-insulator (SOI) platform. The device demonstrates a low coupling loss of 0.27 dB when it is coupled to a cleaved SMF. The polarization-dependent loss (PDL) is less than 0.25 dB, and the 1-dB alignment tolerance is about −2.0~2.0 µm for both vertical and horizontal directions. At the same time, the starting tip width of the tapered waveguide is kept at the level of the lithography limitation at the current commercial silicon photonics fab. This integrated SSC could be an improved design for reducing the coupling loss between the cleaved SMF and the Si waveguide.