UV induced densification during Bragg grating inscription in Ge:SiO2 preforms: interferometric microscopy investigations

The only investigation of Bragg grating in Ge:SiO2 in the direct space known at this date is a view from an optical microscope. Here, we show surface level modulations associated with writing of grating. Our conclusion is that a densification takes place which corresponds to a refractive index increase. Compared to the refractive index change obtained by optical measurement, this accounts for a non-negligible part (7%).

[1]  Steven T. Davey,et al.  Direct observation of UV induced bleaching of 240 nm absorption band in photosensitive germanosilicate glass fibres , 1992 .

[2]  Bertrand Poumellec,et al.  Experimental evidence of two types of photorefractive effects occuring during photoinscriptions of Bragg gratings within germanosilicate fibres , 1993 .

[3]  Bertrand Poumellec,et al.  Behaviour of spectral transmissions of Bragg gratings written in germania-doped fibres: writing and erasing experiments using pulsed or cw uv exposure , 1994 .

[4]  P. J. Lemaire,et al.  High-temperature stability of phase gratings in GeO2-doped optical fibers , 1993 .

[5]  G. Meltz,et al.  Formation of Bragg gratings in optical fibers by a transverse holographic method. , 1989, Optics letters.

[6]  William H Otto,et al.  Compaction Effects in Glass Fibers , 1961 .

[7]  Kenneth O. Hill,et al.  Fiber mode converters: point-by-point fabrication of index gratings, visualization using thermoluminescence, and applications , 1991 .

[8]  F. Ouellette.  Photosensitivity and self-organization in optical fibers and waveguides : 17-18 August 1993, Québec, Canada , 1993 .

[9]  K. Hill,et al.  Photosensitivity in optical fiber waveguides: Application to reflection filter fabrication , 1978 .

[10]  Simon Poole,et al.  Photolytic Index Changes in Optical Fibers , 1993 .

[11]  Makoto Abe,et al.  Photosensitivity in optical fiber and silica-on-substrate waveguides , 1993, Other Conferences.

[12]  Kenneth O. Hill,et al.  Efficient mode conversion in telecommunication fibre using externally written gratings , 1990 .

[13]  D. Hand,et al.  Photoinduced refractive-index changes in germanosilicate fibers. , 1990, Optics letters.