| 摘要 |
PURPOSE:To execute stably a frequency demodulation by superposing a modulating signal to a pressure wave or an electromagnetic wave, and applying it directly to an active area of a semiconductor element. CONSTITUTION:A semiconductor laser element 1 outputs a constant oscillating output laser light under the control of an automatic power/temperature control device 2. On the other hand, a carrier wave supplied to a modulator 5 from an oscillator 3 is subjected to intensity modulation in the modulator 5 by a modulating signal supplied from a signal source 4, and thereafter, applied to an ultrasonic vibrator 7 through a power amplifier 6, and generates an elastic wave. When its elastic wave is converged by a horn 8 and applied from the vertical direction to a laser resonator constituted by the element 1, as for a transmitting output laser light of the element 1, its frequency is modulated in accordance with the modulating signal, and it is made to branch to two by a beam splitter 10 through an optical fiber 9. These two optical beams are reflected 11, 12, respectively, returned to a branch point, made to go straight on and refracted vertically and advanced to the same direction, supplied to a photoelectric converting element 14 through a slit 13, converted to a voltage signal by detecting an intensity variation corresponding to a frequency modulation, amplified 15, and outputted 16. |
