>20%-efficient pulsed frequency doubling of 1532 nm in periodically poled silica fibres

Summary form only given. The recent discovery that thermal poling can produce a permanent and large second-order nonlinearity in silica has made it possible to implement Quasi-phase-Matching (QPM) in glass waveguide/fibres. Despite having a lower effective nonlinear coefficient (d/sub eff/) than crystal waveguides, periodically poled silica fibres (PPSF) and waveguides (PPSWV) can offer longer interaction length (L) for the same bandwidth and higher damage intensity threshold (I), thus keeping high values for the waveguide efficiency-factor d/sub eff//sup 2/L/sup 2/I. In addition they offer high transparency, low cost and straightforward integrability. These features make PPSF/PPSWV ideal for a wide range of QPM processes, such as frequency conversion of fibre lasers and difference frequency generation as a means for wavelength conversion in telecommunications.