The threshold current of semiconductor injection lasers is temperature dependent. To maintain the laser-light output constant with respect to temperature, optical feed-back or thermoelectric temperature control is often employed. In this paper, we describe the properties and advantages of a simple laser-driver module that self-compensates for ambient temperature variation. The temperature dependence of the emitter-base voltage of a silicon bipolar transistor is utilized as the compensating element, thereby requiring no additional circuit components. With such circuitry and high reliability, low- threshold lasers (Ith = 50 mA), miniature hydridized driver modules have been developed that maintain the light output within 1 dB of 5 mW from a 0.25-NA, 50-μm-diam graded-index fiber over a temperature range of-20 to 70° C. The maximum total power consumption of the module is less than 360 mW.
© 1979 Optical Society of AmericaPDF Article