| 摘要 |
1493201 Double heterostructure lasers WESTERN ELECTRIC CO Ltd 14 Jan 1975 [17 Jan 1974] 1634/75 Headings H1C and H1K A double heterostructure junction laser comprises a semiconductor body 10 having wide band gap layers 14 and 18 with a contiguous and relatively narrower gap active layer 16 in between, layer 16 having a P-N junction and a stepped region of greater thickness the dimensions of which are chosen to allow oscillation of only the fundamental transverse mode when the P-N junction is forward biased. Using wave equations, ratios of the thickness of the active layer 16 at its stepped as compared with peripheral portions are plotted against maximum stepped portion width and against transverse wave numbers for the stepped and the peripheral portions. From these families of curves dimensions are chosen for continuous wave operation at room temperature and for pulsed high power operation. A stripe geometry contact 24, of a width chosen relative to the width of the stepped region 32 and the transverse wave number for the peripheral field, helps further to confine the optical field. The layers 14, 16, and 18, may be n Al x Ga 1-x As, p GaAs, and p Al y Ga 1-y As, respectively, on an n GaAs substrate. To avoid problems of contact adhesion a p GaAs layer 20 may be used with zinc diffused on its top surface to get high conductivity. A heat sink may be coupled to the top surface of the laser through the contact 24.
|
