Method and arrangement as well as an optical sensor for optically sensing a parameter of the group of temperature, humidity, or mechanical stress

A sensor arrangement for optically sensing a parameter of the group of temperature, humidity or mechanical stress using at least one optical sensor, the sensor arrangement comprising:

• (a) at least one optical sensor comprising, a chirped Bragg grating and an optical reference reflector, which are optically connected to a first probing signal port, the first probing signal port being configured to feed an optical probing signal to the chirped Bragg grating and to the reference reflector and to output a reflection signal comprising a first partial reflection signal created by the optical reference reflector and a second partial reflection signal created by the chirped Bragg grating as a response to the optical probing signal,
• (b) a group delay measurement device connected to the at least one optical sensor via an optical measurement path, the group delay measurement device being configured:
• (i) to create and output, to the optical measurement path, at least one optical probing signal,
• (ii) to receive, from the optical measurement path, an optical reflection signal created by the at least one optical sensor as a response to the at least one optical probing signal, and
• (iii) to carry out the following method steps:
• creating at least one optical probing signal having a predetermined center wavelength and a bandwidth that lies, for the whole range of the parameter to be sensed, within the reflection bandwidth of the chirped Bragg grating,
• feeding the at least one optical probing signal to the at least one optical sensor,
• receiving at least one optical reflection signal created by the at least one optical sensor, wherein the at least one optical reflection signal comprises, for each of the at least one optical sensor, a first partial reflection signal created by the optical reference reflector and a second partial reflection signal created by the chirped Brag grating of the respective at least one optical sensor,
• measuring the group delay between the first and second partial reflection signal created by each of the at least one optical sensor, and
• determining, for each of the at least one optical sensors, an absolute or relative value of the at least one parameter using the group delay measured and a reference information.