| 摘要 |
PURPOSE:To radiate a laser beam of isotropic high output having a small expensing angle in a single mode by providing a waveguide which has an active layer in a semiconductor, and forming the surface of the waveguide in irregular periodical surface in two dimensions therein, and uniformly exciting the active layer. CONSTITUTION:A waveguide 2 which contains an active layer is formed on a semiconductor substrate 1, and a semiconductor layer 3 is formed thereon, and an irregular periodical surface is formed on the surface of the waveguide 2 in the directions (x) and (y). When a current is flowed to the element or a light is excited, a distributed feedback occurs due to the diffraction grating in both the directions (x) and (y) to generate lasers in the directions (xsi) and (eta), and the sole distributed feedbacks of the grating in the directions (x) and (y) are generated. Accordingly, the laser lights of the directions (xsi) and (eta) are coupled, and the entire surface of the grating is oscillated in the same phase. In this case, the grating having high order grating of even number is provided and the period of the irregular surface is formed near the even times of the laser oscillation half wavelength of the laser in the active layer. Then, the laser light in the waveguide is radiated from the entire surface in the upward perpendicular direction from x-y plane. Thus, the two-dimensional expanding angle can be reduced and the large light output can be obtained. |
