Silicon photonics has attracted tremendous interest from academia and industry, as the fabrication of the silicon family of photonic devices is mostly compatible with the microelectronics process using complementary metal‐oxide semiconductors (CMOS). Herein, three silicon‐family materials are discussed: silicon, silicon nitride, and silica. In addition, hybrid integration with a 2D material, graphene, is examined. First, the material and waveguide properties are reviewed. Second, typical fabrication processes for waveguide devices are introduced. Subsequently, a variety of passive waveguide devices, operating at different physical dimensions covering wavelength, polarization, and mode, are discussed. They correspond to fixed and tunable filters, polarization beam splitters and rotators, and mode conversion and multiplexing devices. These passive waveguide devices play important roles in a wide range of applications including telecom, interconnects, computing, sensing, quantum information processing, bio‐photonics, and energy.

plasmonic or dielectric nanoantennas. [20] Mode conversions between the trans-electric (TE) modes TE 0 , TE 1 , and TE 2 were achieved with a length of ≈10 µm at 1550 nm using silicon nanoantennas on LiNbO 3 or Si 3 N 4 waveguides by simulations. [20] A nanoscale mode converter was theoretically proposed [11] and experimentally demonstrated [21] by introducing a periodic perturbation in its effective refractive index along the propagation direction and a graded effective index profile along its transverse direction. Mode conversion between TE 0 and TE 1 modes was successfully achieved with a length of 23 µm at 1550 nm. However, no experimental results on the crosstalk of the TE mode conversion were provided in the previous reports. [20,21] It is highly desired to miniaturize the device footprint and realize a compact waveguide mode converter.

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The paper presents a piezoresistive absolute micro pressure sensor, which is of great benefits for altitude location. In this investigation, the design, fabrication, and test of the sensor are involved. By analyzing the stress distribution of sensitive elements using finite element method, a novel structure through the introduction of sensitive beams into traditional bossed diaphragm is built up. The proposed configuration presents its advantages in terms of high sensitivity and high overload resistance compared with the conventional bossed diaphragm and flat diaphragm structures. Curve fittings of surface stress and deflection based on ANSYS simulation results are performed to establish the equations about the sensor. Nonlinear optimization by MATLAB is carried out to determine the structure dimensions. The output signals in both static and dynamic environments are evaluated. Silicon bulk micromachining technology is utilized to fabricate the sensor prototype, and the fabrication process is discussed. Experimental results demonstrate the sensor features a high sensitivity of 11.098 μV/V/Pa in the operating range of 500 Pa at room temperature, and a high overload resistance of 200 times overpressure to promise its survival under atmosphere. Due to the excellent performance above, the sensor can be applied in measuring the absolute micro pressure lower than 500 Pa.

We report the fabrication and characterization of the solar-blind AlGaN avalanche photodiodes grown by metal-organic chemical vapor deposition on c-plane sapphire substrate. The fabricated devices with 100 μm diameter active area exhibit a peak responsivity of 79.8 mA/W at 270 nm and zero bias, corresponding to an external quantum efficiency of 37%. Multiplication gains as high as more than 2500 were obtained in these devices.