Frequency multiplication device

PURPOSE: To obtain light of second harmonics generated in the primary mode by providing a waveguide channel of a second section with plural divergent channel branches. CONSTITUTION: Light of a fundamental frequency from a laser diode 12 is coupled to a main channel 20 of a waveguide 18. In the main channel 20, light of the fundamental frequency is converted to light of second harmonics. Light of second harmonics is generated in primary, secondary, and tertiary modes and is made incident on divergent channels 22. When separation distances between divergent channels 22 are increased, light of second harmonics in each mode in the main channel is converted to light of second harmonics in the single mode in each independent divergent channel. Modes of light are divided to independent divergent channels, and it exists as light in the primary mode in each divergent channel. The quantity of light generated in each divergent channel is determined by the frequency of the laser diode 12.