1978 Narrow-band Bragg reflectors in optical fibers英文电子资料.pdf

66 OPTICS LETTERS / Vol. 3, No. 2 / August 1978 Narrow-band Braggreflectors in optical fibers B. S. Kawasaki, K. 0. Hill, D. C. Johnson, and Y. Fujii Communications Research Centre, Department of Communications,Ottawa, Ontario, Canada K2H 8S2 Received April 11, 1978 The formation and characterization of narrow-band-waveguide reflection filters in Ge-doped silica optical fibers is described. The filters can have complex response profiles and are tunable in frequency by mechanical strain. The observation of photosensitivity in the core region to the fiber. The input end of the fiber is clamped in of Ge-doped silica optical fibers was recently reported, the fused quartz jaws of a viselike mount that can be and this effect was used to produce narrow-band- accurately positioned piezoelectrically to permit precise waveguide reflection filters for the construction of a coupling ofthe argon beam to the fiber. The far end of distributed-feedback gas laser. The filters are appar- the fiber is clamped in jaws attached to a section of ently permanently induced in the fibers, and we have spring steel, which serves to apply the desired amount observed no significant decay or degradation of the of longitudinal stress. The spring also servesto reduce devices over periods of several days. the detuning effects of vibrations that may produce In this Letter, we describe in detail the experimental relative motion between the two end mounts. The techniques used to produ