CO_2 laser induced long period gratings in optical microfibers

Long period gratings (LPGs) are fabricated by use of focused high frequency CO 2 laser pulses to periodically modify the transverse dimension of silica microfibers.A 20-period LPG with a 27dB attenuation dip is realized in a microfiber with a diameter of ~6.3µm.The resonant wavelength has a negative temperature coefficient and a high sensitivity to external refractive index.The microfiber LPGs may be useful in micron scale in-fiber devices and sensors.