| 摘要 |
1,097,023. Injection lasers. INTERNATIONAL BUSINESS MACHINES CORPORATION. Jan. 4, 1966 [Feb. 26, 1965], No. 252/66. Heading H1C. In an injection laser the current applied to the contacts is varied and the contacts are shaped so that the sums of the product of current and contact length are made to equal the laser threshold value so that the laser output is subjected to a sweeping action. In the PN junction semiconductor laser of Fig. 1, two electrical contacts 13, 14 are positioned on one side of the junction, Fig. 2 (not shown), and a third common contact is positioned on the opposite side. A full wave rectified sinusoidal current I, is fed to contact 13 and a full wave rectified cosinusoidal current I 2 is fed to contact 14. By shaping the contacts as shown so that the contact 13 is in the shape of the first 90‹ of a sinusoid and contact 14 is in the shape of a cosinusoid the sum of the current and length products along a line parallel to edge 22 for the two contacts is a constant. The maximum lengths along edges 22 and maximum currents I 1 , I 2 are co-ordinated to make the threshold for lasing exist along a unique line that sweeps between edges 22 as a function of time. In a second embodiment, Fig. 3, the laser is in the form of a cylindrical body and having a PN junction parallel with the ends of the cylinder. Two contacts 39, 40 are positioned on the uppermost surface of the cylinder and are shaped to be both sinusoidal and cosinusoidal. When the waveforms of Fig. 4 (not shown), are applied to the contacts the output light beam sweeps radially over a sector of the cylinder defined by the contacts. The currents may be made discontinuous. |
