Characteristics of phase-matched sum-frequency light in optical fibres

Characteristics of phase-matched sum-frequency light in optical fibres is investigated to determine the input power dependence and fibre length dependence. The output power at 0.54 ¿m increases in proportion to the square root of the input power, increasing almost exponentially with increases in the fibre length from 4 m to 17 m and becoming nearly constant above 17 m.