Optoelectronic Noise and Photocurrent Measurement on GaAs/AlGaAs Laser Diode with Single Quantum Well

Abstract

The current progress in optomechatronic applications needs more efficient devices and components with higher reliability, operational lifetime, reduced cost, and dimensions as laser diodes, fast photodetectors, and modulators. The laser is one key technology in a highly industrialized economy. To understand modern efficient laser diode (LD) structures and evaluate their performance, an electrical and optical characterization is necessary. Therefore, low-frequency electrical and optical fluctuation spectra and their cross-correlation factor have been investigated in GaAs/AlGaAs ridge waveguide laser diode with an active region containing a single quantum well layer. It is shown that in the lasing region the intensive Lorentzian-type electrical and optical noises with negative cross-correlation factor are characteristic. This noise is due to charge carrier recombination processes in the interfaces between the active layer and the neighboring layers. To verify it, a complementary insight into the same laser diode structure provided by near-field-induced photocurrent technique with 100 nm spatial resolution is also discussed.