| 摘要 |
PURPOSE:To contrive realizing a variable wavelength light source which has a narrow spectrum width by varying an oscillation wavelength by controlling the refractive index of the optical path in a laser resonator. CONSTITUTION:Light emitted from the nonreflection coating 1 of a semiconductor laser LD1 is made parallel light by a lens LS1. The reflected light from a half mirror HM1 enters in the semiconductor laser LD1 again returning on an optical path. The light of frequency f01 emitted from a nonreflection coating 2 is made parallel light by a lens LS2, passes through an electrooptic element EO1, goes back on the optical path reflected by a mirror M1 and enters in the semiconductor laser LD1 again. As a result, a resonator can be constituted between the half mirror HM1 and the mirror M1. That is, a refractive index (n) can be changed by changing the electric field intensity of the electrooptic element EO1 by a signal source 3 and, as a result, the oscillating frequency f01 can be swept. The laser light is taken out externally via the half mirror HM1. A variable wavelength light source in such a structure has an advantage of narrow width spectrum since the length of the resonator is long and the Q of the resonator is high. |
