LASING OSCILLATIONS IN THE NEGATIVE DIFFERENTIAL RESISTANCE REGION OFTHE DOUBLE-HETEROSTRUCTURE OPTOELECTRONIC SWITCH

In the characterization of the double-heterostructure opto-electronic switch (DOES) in the negative differential resistance (NDR) region, cu rrent oscillations are observed. The oscillations arise from the natur al resonance of the NDR in the test circuit and produce a correspondin g optical output. We observe these oscillations in DOES lasers with br oad area threshold densities of 78 A/cm2 and threshold currents for 10 mum stripes of 15 mA. The optical output during the oscillations is l aser emission since the current easily exceeds the laser threshold. Th e average output power due to the oscillations exceeds the CW power co rresponding to the dc current by more than an order of magnitude.