The analysis of semiconductor optical amplifier applications in Radio-over-Fiber systems of telecommunication
networks is given. In such systems semiconductor optical amplifier can be used for either amplification, modulation or
detection, and also as an universal device.
The distributed control of temperature is an actual task for various application such as oil & gas fields, high-voltage power lines, fire alarm systems etc. The most perspective are optical fiber distributed temperature sensors (DTS). They have advantages on accuracy, resolution and range, but have a high cost. Nevertheless, for some application the accuracy of measurement and localization aren't so important as cost. The results of an experimental study of low-cost Raman based DTS based on standard OTDR are represented.