| 摘要 |
PURPOSE:To vary the oscillating wavelength in a broad range, by forming a comb shaped electrode ultrasonic wave oscillator (IDT) on a light confining layer so that the pitches of the oscillator are different depending on positions, thereby making the oscillating frequency vary. CONSTITUTION:When an electric field of a frequency (f) is applied to an IDT10, an SAW is generated and proparated in the light emitting direction along a p type GaAs layer 3. Single mode vertical oscillation can be generated by the SAW. Laser light having a wavelength lambda shown by an expressionIis obtained, where LAMBDA is the wavelength of the SAW. When the frequency (f) of the applied electric field is varied, DELTAlambda is obtained by an expression II, where V is the propagating speed of the SAW. When the oscillating frequency of the IDT10 is varied by DELTAf, the oscillating wavelength can be varied by DELTAlambda. The pitches between the electrodes are different. With the frequencies f1-fn corresponding to the different wavelengths LAMBDA1-LAMBDAn of the SAW as the center, each frequency can be varied by DELTAf. The corresponding oscillating wavelength can be varied by DELTAlambda with lambda1-lambdan as the centers. |
