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HL: Fachverband Halbleiterphysik
HL 48: Semiconductor Lasers
HL 48.5: Talk
Thursday, March 25, 2010, 10:30–10:45, H13
40 GHz hybrid mode-locking in a monolithic quantum dot laser — •Dejan Arsenijevic, Gerrit Fiol, and Dieter Bimberg — Institut für Festkörperphysik, Technische Universität Berlin, EW 5-2, Hardenbergstr. 36, 10623 Berlin, Germany
The quantum dot mode-locked lasers presented here are processed into ridge waveguide structure from material grown by molecular beam epitaxy and contain 15 stacks of InGaAs/GaAs quantum dots emitting at 1.3 µm. To enhance temperature stability the material is p-doped. The lasers having an overall length of 1 mm are separated into two sections (900 µm gain, 100 µm absorber). For hybrid mode-locking in addition to the DC-biasing of these two sections a RF signal was applied to the absorber. The emitted optical pulses for varying frequency and power of the RF source as well as different heat sink temperatures are analyzed by auto-correlation and electrical spectra measurements. The pulse width ranges from below 2 ps to about 8 ps. Although no change in pulse width is found by switching the operation mode from passive to hybrid mode-locking a decrease in optical timing jitter is observed. The maximum locking range for one operating point is 30 MHz and in addition can be linked to the widths of the pulses. The dependence of the locking range on the RF power is found to be linear. Interestingly the region of hybrid mode locking is asymmetric compared to the passive mode-locked frequency.