We present an advanced demodulation technique for a fiber-optics interferometric current transducer. A quadrature sampling method with internal triggers was adopted for structural simplification and cost-effective phase demodulation. The internal triggers for quadrature signal processing were generated at zero crossing points of an ac-coupled reference signal, which was distinguished from the current-induced interference signal by utilizing fiber Bragg grating. Phase variation was extracted from the arctangent demodulation process. The proposed technique demonstrated accurate and stable phase demodulations performance and better than that of the conventional lock-in amp demodulation.
We present biomimetic antireflective AlInP nanostructures fabricated by inductively coupled plasma etching using Ag etch masks, which were easily formed by spin-coating Ag ink and subsequent sintering process on a hotplate without any lithography process and complicated equipments, for compound semiconductor based solar cell applications. This lithography-free technique is a simple, cost-effective, and high throughput method. The fabricated AlInP nanostructures demonstrated drastically reduced the hemispherical reflectance and solar-weighted reflectance (SWR) compared to that of bulk AlInP in the wavelength range of 300-870 nm. The incident angle-dependent SWR of the AlInP nanostructures remained below 4% up to an incident angle of 50°. Therefore, the biomimetic antireflective AlInP nanostructures fabricated by using the lithography-free method hold great potential for use in compound semiconductor based solar cell applications.