| 摘要 |
PURPOSE:To isolate currents for generating laser light and for tuning the light and to make it possible to couple the light between active layers for generating and tuning the laser light, by arranging the first and second stripe-shaped active layers in close proximity, and tuning the oscillating wavelength of the laser light generated in the first active layer at the DBR region of the second active layer. CONSTITUTION:A mesa shaped stripe is formed, and completely isolated two active layers 12 and 13 are arranged in close proximity. A diffraction grating 25 is formed beneath the active layer 13, i.e., on the side of a substrate 20 through a guide layer 24. Therefore currents can be made to flow through the active layers 12 and 13 in completely isolated mode. The light, which is generated in the active layer 12, is coupled to the active layer 13 during the propagation in the direction of the stripe. The light undergoes feedback in a DBR region 13A. The Bragg wavelength is controlled depending on the current, which is made to flow through the DBR region 13A, i.e., the active layer 13. Thus the oscillating wavelength can be tuned. Said optical coupling can be readily obtained by selecting the width of the active layers 12 and 13 or the interval between the layers 12 and 13.
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