The invention relates to a method for optically sensing a parameter of the group of temperature, humidity or mechanical stress using at least one optical sensor which includes a chirped Bragg grating and an optical reference reflector. The method includes the steps of; 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 includes, 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. The invention further relates to a sensor arrangement for implementing the method as well as to an optical sensor that is suitable for being used in such a sensor arrangement.

Aspects described herein include an optical apparatus comprising an input port configured to receive an optical signal comprising a plurality of wavelengths, and a plurality of output ports. Each output port is configured to output a respective wavelength of the plurality of wavelengths. The optical apparatus further comprises a first plurality of two-mode Bragg gratings in a cascaded arrangement. Each grating of the first plurality of two-mode Bragg gratings is configured to reflect a respective wavelength of the plurality of wavelengths toward a respective output port of the plurality of output ports, and transmit any remaining wavelengths of the plurality of wavelengths.

An optical sensor system with two or more optical sensors; two or more receivers; and an optical de-multiplexing system. Each optical sensor includes a fibre grating with a different wavelength characteristic. Each receiver includes a slope filter and a light detector and is associated with a respective one of the optical sensors. The optical de-multiplexing system is arranged to route light from each of the optical sensors to its associated receiver based on a wavelength of the light.

Aspects described herein include an optical apparatus comprising a multiple-stage arrangement of two-mode Bragg gratings comprising: at least a first Bragg grating of a first stage. The first Bragg grating is configured to transmit a first two wavelengths and to reflect a second two wavelengths of a received optical signal. The optical apparatus further comprises a second Bragg grating of a second stage. The second Bragg grating is configured to transmit one of the first two wavelengths and to reflect an other of the first two wavelengths. The optical apparatus further comprises a third Bragg grating of the second stage. The third Bragg grating is configured to transmit one of the second two wavelengths and to reflect an other of the second two wavelengths.

Fiber Bragg grating interrogation and sensing used for strain and temperature measurements. A simple, broadband light source is used to interrogate one or more fiber Bragg grating (FBG). Specifically, a packaged LED is coupled to fiber, the light therefrom is reflected off a uniform FBG. The reflected light is subsequently analyzed using a filter and a plurality of Si photodetectors. In particular, the filter is a chirped FBG or an optically coated filter, in accordance with some embodiments. Measurement analysis is performed by ratio of intensities at the plurality of detectors, at least in part.

Aspects described herein include an optical apparatus comprising an input port configured to receive an optical signal comprising a plurality of wavelengths, and a plurality of output ports. Each output port is configured to output a respective wavelength of the plurality of wavelengths. The optical apparatus further comprises a first plurality of two-mode Bragg gratings in a cascaded arrangement. Each grating of the first plurality of two-mode Bragg gratings is configured to reflect a respective wavelength of the plurality of wavelengths toward a respective output port of the plurality of output ports, and transmit any remaining wavelengths of the plurality of wavelengths.

Aspects described herein include an optical apparatus comprising at least a first Bragg grating of a first stage. The first Bragg grating is configured to transmit a first two wavelengths and to reflect a second two wavelengths of a received optical signal. The optical apparatus further comprises a second Bragg grating of a second stage. The second Bragg grating is configured to transmit one of the first two wavelengths and to reflect the other of the first two wavelengths. The optical apparatus further comprises a third Bragg grating of the second stage. The third Bragg grating is configured to transmit one of the second two wavelengths and to reflect the other of the second two wavelengths.

Aspects described herein include an optical apparatus comprising at least a first Bragg grating of a first stage. The first Bragg grating is configured to transmit a first two wavelengths and to reflect a second two wavelengths of a received optical signal. The optical apparatus further comprises a second Bragg grating of a second stage. The second Bragg grating is configured to transmit one of the first two wavelengths and to reflect the other of the first two wavelengths. The optical apparatus further comprises a third Bragg grating of the second stage. The third Bragg grating is configured to transmit one of the second two wavelengths and to reflect the other of the second two wavelengths.

The invention relates to a method for optically sensing a parameter of the group of temperature, humidity or mechanical stress using at least one optical sensor which includes a chirped Bragg grating and an optical reference reflector. The method includes the steps of; 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 includes, 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. The invention further relates to a sensor arrangement for implementing the method as well as to an optical sensor that is suitable for being used in such a sensor arrangement.

Fiber Bragg grating interrogation and sensing used for strain and temperature measurements. A simple, broadband light source is used to interrogate one or more fiber Bragg grating (FBG). Specifically, a packaged LED is coupled to fiber, the light therefrom is reflected off a uniform FBG. The reflected light is subsequently analyzed using a filter and a plurality of Si photodetectors. In particular, the filter is a chirped FBG or an optically coated filter, in accordance with some embodiments. Measurement analysis is performed by ratio of intensities at the plurality of detectors, at least in part.