Optical signal to noise ratio monitoring with Hi-Bi fiber Bragg grating

In this work is presented a technique to measure the optical signal to noise ratio (OSNR) of a channel, based on a high birefringent fiber Bragg grating (HiBi FBG). The HiBI FBG reflects at two different spectral bands, these bands are related with the effective refractive indexes for the optical field components along the two optical axis of the HiBi fiber. For a channel with a polarized signal and depolarized noise it is possible to obtain the OSNR by measuring the optical powers of the two reflections bands separately. It was experimentally confirmed that this method is able to retrieve the OSNR of one optical channel for a range [0, 22]dB, with a maximum error of 1.6 dB.