A new fiber-optic pH sensor based on a thin-core fiber modal interferometer with electrostatic self-assembled nanocoating is presented. After inserting a segment of thin-core fiber into a standard single-mode fiber, high-order cladding modes are excited and interfere with the core mode to form an in-fiber modal interferometer. The side surface of the sensor is then deposited with poly(allylamin...

Determination of the characteristics pH sensor using U-shaped optical fiber was carried out with various varieties, namely length without a coat, indentation diameter, and number imperfections. Optical as light transmission medium is used to detect level solution. The output read on OPM in form power. best characteristic obtained imperfections, imperfections 3 value range 32.0 µW, sensitivity 3...

A low-power, high sensitivity, very low-cost light emitting diode (LED)-based device developed for low-cost sensor networks was modified with bromocresol green membrane to work as a solid-state pH sensor. In this approach, a reverse-biased LED functioning as a photodiode is coupled with a second LED configured in conventional emission mode. A simple timer circuit measures how long (in microseco...