Abstract

Crystalline fibres are produced by the Laser Heated Miniature Pedestal Growth technique (LHMPG), as developed by Burrus and Stone¹ and later improved on by Fejer et al. at Stanford.² In LHMPG, the tip of a source rod of the material of interest, typically 0.5 mm in diameter, is heated to melting point by the focused beam from CO₂ laser. A properly orientated seed crystal is dipped into the molten zone and then withdrawn at a rate of ~mm.min^-1 to form a fibre. If it is extracted faster than the source material is replenished, then by conservation of melt volume, the crystalline fibre grows at some constant fraction of the source rod diameter. Diameters are typically in the range 50-500 μm, with lengths limited by the pulling mechanism. In this way doped and undoped fibres may be obtained for applications as laser media, frequency mixers, parametric oscillators, electro-optic modulators, etc., compatible with diode laser sources, waveguides, and conventional fibre. Normally weak nonlinear optical effects are expected to be enhanced and phase matching may be assisted by correct choice of modes.

© 1994 IEEE