Abstract

Until fairly recently, second harmonic generation in specially treated glasses and glass fibres has been more of scientific that of practical interest, owing to the low attained levels of induced nonlinearity (several orders of magnitude less than in lithium niobate). During the past three years, however, a number of glass poling techniques have emerged that produce second order nonlinearities approaching 1 pm/V. Such high levels of nonlinearity are sufficient to be useful for parametric frequency conversion and electro-optic light modulation. These new poling techniques are: thermal poling of fused silica^1-3 at 250-300°C under an applied electric field (the second-order nonlinearity appears in a thin layer just under the anode), thermal poling of tellurite glasses,⁴ corona poling of glass waveguides,⁵ and charge implantation by exposure to an electron-beam.^2,6

© 1994 IEEE