| 摘要 |
<p>PURPOSE:To permit an optical wavelength multiplex communication using near-by wavelengths by providing a filter layer interrupting the light having shorter wavelengths than the principal wavelength above the double hetero structure in a light-emitting element in order to narrow the spectral line half width. CONSTITUTION:On an N type GaAs substrate 11, an N type GaAlAs filter layer 12 is grown by the liquid phase epitaxy. On this, an N type GaAlAs layer 13 having a wider forbidden band width than the layer 12 is grown. On this, moreover, a P type GaAlAs layer 14 having a narrower forbidden band width than the layer 13 is grown. The layer 14 is coated with a P type GaAlAs layer 15 having a wider forbidden band width than the layer 14 to form a double hetero structure together with the layer 13. Then the layer 15 is covered with a film 16, in which a window is opened to provide an electrode 18. An opening is made on the substrate 11 side, and an optical fiber 19 is inserted. The surface of the substrate 11 surrounding the fiber 19 is coated with an annular positive electrode 17. Thus, the layer 12 prevents the bottom of the spectrum from spreading over the short wavelength side.</p> |
