%0 Electronic Article %A M.C. Farries %A P.ST.J. Russell %A M.E. Fermann %A D.N. Payne %K spectral bandwidth %K self written grating %K 0.5 percent %K fused SiO2 %K second harmonic generation in fibre %K second order nonlinear susceptibility grating %K SHG %K phase-matched generation of second-harmonic %K weak non-phase-matched SH signal %K axially periodic pattern of colour centres %K quadrupole polarisation %K mechanism %X A mechanism for phase-matched generation of second-harmonic (SH) light in an optical fibre has been experimentally and theoretically studied. A weak non-phase-matched SH signal, created via the quadrupole polarisation, initiates the self-writing of an axially periodic pattern of colour centres which is postulated to lead to the growth of a χ (2) grating. The grating (at the phase-match period) gives rise to SH generation at efficiencies of 0.5%. The spectral bandwidth of this χ (2) grating is 0.24 nm. %@ 0013-5194 %T Second-harmonic generation in an optical fibre by self-written χ(2) grating %B Electronics Letters %D March 1987 %V 23 %N 7 %P 322-324 %I Institution of Engineering and Technology %U https://digital-library.theiet.org/;jsessionid=3ob15h9a449io.x-iet-live-01content/journals/10.1049/el_19870239 %G EN