| 摘要 |
1,188,848. Semi-conductor lasers. GENERAL ELECTRIC CO. 18 Sept., 1967 [14 Oct., 1966], No. 42476/67. Heading H1C. Pulse width modulated output light pulses are obtained from a semi-conductor junction laser by applying an amplitude modulated bias signal superimposed by a train of constant amplitude current pulses to the laser diode. The interval between initiation of current and occurrence of stimulated emission in a GaAs laser is determined by the amplitude of the supplied current. Hence if the amplitude increases the delay decreases and since the output pulse of the laser ceases at the same time as the termination of the applied pulse, pulse width modulation of the output light pulse is achieved, Fig. 2 (not shown). Clock pulse generator 13 applies a constant amplitude pulse train to laser diode 10 together with a unipolar modulated bias signal through diode 19, the modulated bias signal being applied constantly to the laser 10 and having a peak value less than the threshold lasing value. The laser thus produces a pulse of light in response to each pulse of the train and begins lasing after a delay following the leading edge of the pulse dependent on the instantaneous value of the modulated bias current. |
