| 摘要 |
PURPOSE:To make it possible to arbitrarily tune and frequency-modulate the frequency of a semiconductor laser which oscillates at a single frequency by applying a voltage across both sides of the waveguide layer for output in order to vary the refractive index thereof. CONSTITUTION:In the distribution reflecting type laser; of the light emitted from the gain medium portion 10, only the light having the specified frequency determined by the grid cycle of the distribution reflectors 20 on both sides thereof is reflected, and of said light, only the light having a specified frquency is socillated as an output light. Said frequency is determined by the equivalent reflective indexes of the gain medium portion 10 and the reflector portions 20. Therefore, the oscillation frequency can be arbitrarily varied within a certain range by applying an external voltage from an external signal voltage source 25 to the reflector portions 20 to form a depletion layer in the ouputting waveguide layer 14 and varying the reflective index of the layer 14 by the electric field produced at the time. In this case, the oscillation frequency can be tuned to a desired frequency by a DC voltage V0. Thereby, frequency modulation can be effected by superposing an AC voltage V1 thereon. |
