Dresden 2014 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 97: Semiconductor laser II: Microcavities and quantum-dot laser

HL 97.3: Talk

Thursday, April 3, 2014, 16:00–16:15, POT 051

Jitter Reduction by Optical Feedback of Passively Mode-locked Quantum-Dot Lasers — •Marc Spiegelberg¹, Dejan Arsenijević¹, Moritz Kleinert², and Dieter Bimberg¹ — ¹Technische Universität Berlin, Institut für Festkörperphysik, Berlin, Germany — ²Fraunhofer Heinrich Hertz Institut, Berlin, Germany

Monolithically integrated two-section quantum-dot mode-locked lasers (MLL) providing optical pulse trains at several tens of Gigahertz are ideal candidates for applications in optical communication systems, e.g. as an optical clock or as a transmitter. Low jitter of the pulse comb is at least as crucial as repetition rates of or beyond 40GHz. The integrated jitter of passively MLLs is of the order of a few picoseconds. For hybrid mode-locking, a standard technique to reduce the jitter, an external electrical signal source is necessary, which is costly. Optical self-feedback (OFB), where a part of the MLL light is injected back into the device, is used here as a simple and effective way to reduce the jitter and to tune the repetition frequency of the MLL at the same time. For the first time, five different regimes of OFB are identified, depending on the OFB parameters: overall fiber length, feedback strength and the relative delay between emitted and injected pulses. But only one, the resonant regime, yield a jitter reduction of 94.2% down to 219fs. In this regime the repetition frequency of the MLL shows a linear dependence on the delay and can be tuned within 6.5MHz.