| 摘要 |
PURPOSE:To obtain a semiconductor laser capable of lowering a threshold and modulating laser oscillation beams at high speed by forming a quantum well active layer, barrier layers, which are shaped on both sides of the quantum well active layer and have thickness through which electrons and holes can be tunneled, and an n-type clad layer aud a p-type Clad layer formed on both sides of the barrier layers. CONSTITUTION:When the energy difference of a quantum level in a quantum well active layer 21 and the bottoms of the conduction bands of AlyGa1-yAs clad layers 23, 24 is represented by E1, a resonance tunnel is generated when applied voltage to the n<+>-AlyGa1-yAs clad layer 23 and the p<+>-AlyGa1-yAs layer 24 reaches 2E1/e in the same manner as a diode. Electron waves intruding into the quantum well active layer 21 are intensified resonantly at that time, and high electron density is attained in the quantum well active layer 21, thus allowing the lowering of the threshold of a laser. Since laser power is increased by the high electron density at the same time, the negative resistance of applied voltage-current characteristics is acquired, and highest oscillation is generated at a bias, where negative resistance is maximized, and the laser power is also modulated at said frequency.
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