| 摘要 |
PURPOSE:To obtain stable wavelength variable effect by disposing a member having piezoelectric effect parallel to the surface formed with a diffraction grating of a semiconductor laser having a periodic structure of the grating in a resonator to enable to apply an AC voltage. CONSTITUTION:A diffraction grating 2 is formed on a substrate 1, and to avoid the influence of the substrate 1, a waveguide layer 3 is formed, an active layer 4, a buffer layer 5, a clad layer 6, and electrodes 7, 8 are formed. In order to vary the oscillating frequency, only one layer 10 having piezoelectric effect is newly added to the DFB laser operating by modulating a current source 9. The original osicllation vertical mode spectrum is formed to be sufficiently narrow in width of spectrum by using the stabilized current source as the current source 12 to the semiconductor laser, a signal source 11 for applying a voltage to the layer 10 of the piezoelectric material is used to vary the oscillating wavelength of the laser so that the period of the diffraction grating of the DFB laser may vary. |
