Full Analog Fiber Optic Monitoring System Based on Arrayed Waveguide Grating

Fiber Optic Sensors (FOS), whose advantages have made them widely used in many applications, are up to now not so diffusely used for the monitoring of industrial processes, mainly due to two aspects: the expensiveness and complexity of the sensors monitoring systems. For these reasons, these sensor systems are usually substituted with low performance but easier to manage sensors, in agreement with industrial monitoring standards. The read-out system described in this document overcomes the limitations suffered by the commonly used FOS interrogation system and extends the fields in which FOS can be employed. The circuit handles the transduction of an optical signal to an electrical signal, going from wavelength encoding to voltage or current. Moreover, the proposed system relies on a totally analog and fully modular circuit in combination with a power fluctuation rejection circuit. The system is tested through temperature measurements highlighting it's characteristics of reliability and repeatability. The temperature variation is given by a heat plate and monitored with a calibrated sensor close to the Fiber Bragg Grating sensor under test.