at least one sensor including:

at least one substrate having a first and a second surface and a substrate material between said first and second surfaces,

at least a pair of fiber guides formed in said substrate material extending therethrough between said first and second surfaces,

a diaphragm layer formed on said first surface of said at least one substrate, and

at least a pair of optical fibers received in said at least a pair of fiber guides, each of said at least a pair of optical fibers having a fiber tip displaced from said diaphragm layer by a predetermined distance, thereby forming a sensing interferometer having a Fabry-Perot cavity defined between said fiber tip and said diaphragm layer, said fiber tip and said diaphragm layer being optically reflective to form a pair of reflective surfaces of said sensing interferometer; and

at least a further sensor including:

a further substrate having a first and a second surface and a substrate material between said first and second surfaces of said further substrate, said further substrate being attached by said second surface thereof to said diaphragm layer of said at least one substrate,

another diaphragm layer formed on said first surface of said further substrate, and

at least one fiber guide formed in said further substrate in alignment with one of said at least a pair of said fiber guides of said at least one substrate, wherein one of said pair of said optical fibers is received in said at least one fiber guide formed in said further substrate through said one of said at least a pair of said fiber guides of said at least one substrate; and

a data acquisition and processing unit coupled to said at least a pair of optical fibers for calculating an acoustic/vibration parameter to be measured.