Dresden 2006 – scientific programme

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HL: Halbleiterphysik

HL 49: Devices

HL 49.1: Talk

Thursday, March 30, 2006, 15:15–15:30, BEY 154

80 GHz Passive Mode Locking of InGaAs Quantum Dot Lasers Emitting at 1.3 µm — •Gerrit Fiol¹, M. Kuntz¹, F. Hopfer¹, M. Lämmlin¹, C. Szewc¹, D. Bimberg¹, A.R. Kovsh², and N.N. Ledentsov^1,2 — ¹Technische Universität Berlin, Institut für Festkörperphysik, PN 5-2, Hardenbergstrasse 36, 10623 Berlin, Germany — ²NL Nanosemiconductor GmbH, Konrad-Adenauer-Allee 11, 44263 Dortmund, Germany

The sample structure incorporating a 15-fold stack of InGaAs QDs emitting at 1.3 µm was grown by MBE. The wafers were processed into two-sectional ridge waveguide structures with a 20 µm gap between the sections to ensure good electrical insulation. All samples were mounted p-side up and were electrically contacted with a two-channel probe head. The section lengths of the devices were 1800/200 µm for the 20 GHz device, 900/100 µm for the 40 GHz device and 450/50 µm for the 80 GHz device. An autocorrelator was used to measure the pulse width. The 20 GHz device was passively mode-locked. The shortest deconvoluted pulse width best fitted by a sech2 shaped pulse was 900 fs, which is the shortest pulse width for all devices we investigated. The 40 GHz device was hybridly and passively mode-locked. The deconvoluted pulse width ranged from 1.8 to 6 ps with a time-bandwidth-product of ΔτΔν=0.72 for the shortest pulse width. The locking range for hybrid mode locking was 7 MHz at a RF power of 7dBm. The minimum pulse width we achieved at 80 GHz was 1.5 ps. The corresponding spectrum yields a time-bandwidth product of 1.7, which is well above the Fourier transform limit of 0.32.