Eight-wavelength Er-doped fiber lasers with lasing wavelength separations of ~1.6 and ~0.8 nm , respectively, have been achieved by use of overlap-written fiber Bragg gratings (OWFBG's) in the fiber lasers and by cooling of the Er-doped fiber with liquid N(2) . Our experiment shows that by utilizing the OWFBG's to select the lasing wavelengths one can achieve fiber lasers with lasing wavelengths and lasing wavelength separations that match the International Telecommunication Union channel-allocation grid well.

We derive an analytical expression for differential group delay of spun and twisted fibers, which should provide valuable guidance for optimization of such parameters to produce low polarization mode dispersion fiber.

No abstract

This paper demonstrates a novel dual-period fiber grating sensor which can measure strain and temperature simultaneously. The dual-period fiber grating consists of a long-period fiber grating(LPG) and a fiber Bragg grating(FBG) which are written in the same section of an uncovered hydrogen-loaded fiber orderly. As is known, the Bragg wavelength of LPG and that of FBG have the different sensitivity of strain and temperature, then strain and temperature can be determined simultaneously by measuring the two transmitted Bragg wavelengths of the dual-period fiber grating. The accuracy of the sensor in measuring strain and temperature is estimated to be I 6 i.t C in a range from 0 to 1700 i-' c and from 20 to 2O'C respectively.

No abstract