| 摘要 |
PURPOSE:To obtain a compact variable-wavelength light source characterized by quick response speed, by coupling a variable-wavelength optical resonance circuit constituted by an ultrasonic wave deflector and a reflector to a semiconductor laser unit, changing an ultrasonic wave frequency, thereby changing the wavelength of emitted light. CONSTITUTION:Light is emitted from an emitting end surface 2, on which a reflectionless coating is applied, in a semiconductor laser unit 1. The light is inputted in an acoustooptic medium 5A through a collimate lens 4 at an angle theta with respect to the wave front of an ultrasonic wave. When the wavelenght of the incident light satisfies Bragg conditions, Bragg diffraction light is emitted at an angle theta. The light is inputted to a planar reflector 8 at a right angle. The light is further inputted to an output fiber 10 through a convergent lens 9. Part of the Bragg diffraction light, which is reflected by the reflecting mirror 8, is inputted to the acoustooptic medium 5A again and undergoes Bragg diffraction again. Part of the diffracted light is reflected by a light emitting end surface 3 of the semiconductor laser unit 1 and returned to the light emitting end surface 2. A variable-wavelength optical resonance circuit is constituted by a ultrasonic wave deflector 5 and the planar reflector 8. The resonance wavelength can be changed by changing the frequency of the ultrasonic wave.
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