Additionally current ndash voltage characteristics exhibited some abnormal behavior
Fig. 4. Current–voltage–light characteristics for ZSTK474 150-µm-wide device in cw operation. The insets show the cw lasing spectra at heat-sink temperatures of 80–97 K, and emission spectra at 80 K with several injection currents before threshold.Figure optionsDownload full-size imageDownload as PowerPoint slide
Fig. 5. Light–current curves for the broad-area IC laser in pulsed mode at temperatures of 80 K to 130 K. The arrows point to threshold currents where spectra were taken. The inset shows the pulsed spectra at several temperatures.Figure optionsDownload full-size imageDownload as PowerPoint slide
AcknowledgmentsThis work was supported by the National Science Foundation (ECCS-1002202 and IIP-1346307), and by C-SPIN, the Oklahoma/Arkansas MRSEC (NSF DMR-0520550).
A3. Molecular beam epitaxy; B1. Gallium compounds; B2. Semiconducting Gallium Arsenide; B3. Laser diode
Regarding the laser diode for tunable laser, broad gain profile is one of the very desirable properties. Growth of self-assembled QDs in Stranski–Krastanov (SK) mode has been demonstrated as a very efficient way to obtain high density of zero-dimensional nanostructures . In addition, these densely packed QDs have very good optical properties and can be used as active material for high performance QD lasers , ,  and . Due to the basic nature of the SK growth mode, the QD assembly always has relative broad size distribution, leading to a gain profile much wider than that of QWs. This feature is very useful for broadly tunable lasers. Previously, we studied external cavity tunable InAs/GaAs and InAs/InP  QD lasers with broad tunable range in Littrow configuration. In dark reactions work, we modified the setup by using a DMD to generate optical feedback, which brings unique features and flexibility to the ECL system.