Q-switching instability in a mode-locked semiconductor laser

Рачинский, Дмитрий; Vladimirov, Andrei; Bandelow, U.; Hüttl, B.; Kaiser, R.

doi:10.1364/josab.23.000663

Cited by 30 publications

(28 citation statements)

References 15 publications

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“…Increase of the parameter s leads usually to an increase of the ML stability domain and improvement of the pulse quality. 7,14,15 A similar decrease of the locking range is observed with the increase of the spectral filtering width ␥ which also leads to a decrease of the pulse width, see Fig. 4͑a͒.…”

supporting

confidence: 67%

Hybrid mode-locking in a 40 GHz monolithic quantum dot laser

Viktorov¹,

Mandel²,

Vladimirov

et al. 2009

CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference

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Hybrid mode-locking in monolithic quantum dot ͑QD͒ lasers is studied experimentally and theoretically. A strong asymmetry of the locking range with respect to the passive mode locking frequency is observed. The width of this range increases linearly with the modulation amplitude for all operating parameters. Maximum locking range found is 30 MHz. The results of a numerical analysis performed using a set of delay-differential equations taking into account carrier exchange between QDs and wetting layer are in agreement with experiments and indicate that a spectral filtering element could improve locking characteristics. © 2010 American Institute of Physics. ͓doi:10.1063/1.3279136͔Quantum dot ͑QD͒ mode-locked lasers are promising for telecom applications since they demonstrate a number of important advantages as compared to standard quantum well ͑QW͒ devices.1-3 However, tailoring the characteristics of QD lasers for specific applications is a challenging issue. An important characteristics of hybrid mode-locking ͑ML͒, a commonly used technique for improving quality of modelocked pulses, is the frequency locking range where the pulse repetition frequency can be synchronized to that of the external signal. Since the first reports on 10 GHz hybrid ML ͑Ref. 4͒ a significant reduction of the pulse jitter has been demonstrated using hybrid ML with promising results of 124 and 190 fs for 40 GHz mode-locked lasers. 5,6 However, the so far achieved locking range for hybrid ML in QD lasers is smaller than that reported for QW devices. This fact was recently discussed in Ref. 7.In this letter we study, experimentally and theoretically, the characteristics of the hybrid mode-locked regime in QD lasers with a pulse repetition rate of 40 GHz. We find that stable hybrid ML in QD lasers shows a locking range up to a few tens of MHz demonstrating a strong asymmetry with respect to the frequency of the free running passively modelocked laser. We also discuss a possible improvement of hybrid ML locking range, and describe bifurcation mechanisms responsible for locking and unlocking between the fundamental ML regime and the external RF modulation.Experimental investigations have been performed using a monolithic 40 GHz QD laser integrated in a module, comprising a standard single mode fiber pigtail and a microwave port. It is based on a two-section QD laser diode with a total length of 1 mm ͑saturable absorber length is 1/10 of the total length͒ and a 4 m wide ridge waveguide structure. The active zone of the device contains 15 layers of self-organized InAs QDs emitting at 1.3 m embedded in InGaAs quantum wells. 6 The threshold current density of the diode is 360 A / cm 2 .In the absence of the external modulation, the laser exhibits passive ML, which remains stable in a wide range of operating parameters. External modulation of the voltage V is applied to the absorber section of the device and has the form of V ͓1+a cos͑⍀t͔͒ where a, ⍀, and V are the amplitude, frequency, and dc component of the reverse bias, respectively.In order t...

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confidence: 67%

Hybrid mode-locking in a 40 GHz monolithic quantum dot laser

Viktorov¹,

Mandel²,

Vladimirov

et al. 2009

CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference

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“…One of them lies around G 0 350 and involves a transition to a quasiperiodic solution with four pulses per round-trip. The other lies on the single-pulse branch, at G 0 90, and can be identified as a Q-switching instability [31], as we have found the envelope of the resulting oscillatory pulse train to be modulated at the Q-switching frequency. Q-switching is a process in which the laser response undergoes a periodic modulation on a time scale much larger than the round-trip time, typically on the order of the geometric mean of the photon and gain medium population lifetimes in the cavity.…”

Section: Bifurcation Diagramsmentioning

confidence: 72%

Pulse interaction via gain and loss dynamics in passive mode locking

Nizette

Рачинский

Vladimirov

et al. 2006

Physica D: Nonlinear Phenomena

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“…Solving the laser equations for the two stages analytically and gluing the solutions one obtains the map governing the transformation of the pulse energy, saturable gain, and saturable loss after a complete round trip in the cavity. We skip the details of these calculations, which are described in Rachinskii and Vladimirov (2004), and present only the results of the analytical study of this map (see Fig. 8).…”

Section: Delay-differential Equation Modelmentioning

confidence: 99%

40 GHz Mode-Locked Semiconductor Lasers: Theory, Simulations and Experiment

et al. 2006

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Optical and Quantum Electronics (2006) 38:495-512 © Springer 2006 40 GHz mode-locked semiconductor lasers: theory, simulations and experiment u w e b a n d e l o w 1, * , m i n d a u g a s r a d z i u n a s 1 , a n d r e i v l a d i m i r o v 1 , b e r n d hü t t l 2 and r o n a l d k a i s e r 2Abstract. We study both theoretically and experimentally typical operation regimes of 40 GHz monolithic mode-locked lasers. The underlying Traveling Wave Equation model reveals quantitative agreement for characteristics of the fundamental mode-locking as pulse width and repetition frequency tuning, as well as qualitative agreement with the experiments for other dynamic regimes. Especially the appearance of stable harmonic mode-locking at 80 GHz has been predicted theoretically and confirmed by measurements. Furthermore, we derive and apply a simplified Delay-Differential-Equation model which guides us to a qualitative analysis of bifurcations responsible for the appearance and the breakup of different mode-locking regimes. Higher harmonics of mode-locking are predicted by this model as well.

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Q-switching instability in a mode-locked semiconductor laser

Cited by 30 publications

References 15 publications

Hybrid mode-locking in a 40 GHz monolithic quantum dot laser

Hybrid mode-locking in a 40 GHz monolithic quantum dot laser

Pulse interaction via gain and loss dynamics in passive mode locking

40 GHz Mode-Locked Semiconductor Lasers: Theory, Simulations and Experiment

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