Modulation of Coherently Coupled Phased Photonic Crystal Vertical Cavity Laser Arrays

Fryslie, Stewart T. M.; Gao, Zihe; Dave, Harshil; Thompson, Bradley J.; Lakomy, Katherine; Lin, Shiwei; Decker, Patrick J.; McElfresh, D. K.; Schutt-Ainé, José E.; Choquette, Kent D.

doi:10.1109/jstqe.2017.2699630

Cited by 55 publications

(38 citation statements)

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“…S can be increased with higher pump current and smaller mode volume, τ p can be decreased with lower mirror reflectivities and a can be optimized by material engineering. Alternative concepts to overcome the bandwidth bottleneck are actively pursued, for example, in coupled-cavity VC-SEL arrays [8] or photonic crystal nanocavity lasers where f R > 100 GHz was attained at cryogenic temperature [9].…”

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confidence: 99%

Ultrafast spin-lasers

Lindemann

Pusch

et al. 2019

Nature

186

134

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The appeal of lasers can be attributed to both their ubiquitous applications and their role as model systems for elucidating nonequilibrium and cooperative phenomena [1]. Introducing novel concepts in lasers thus has a potential for both applied and fundamental implications [2]. Here we experimentally demonstrate that the coupling between carrier spin and light polarization in common semiconductor lasers can enable room-temperature modulation frequencies above 200 GHz, exceeding by nearly an order of magnitude the best conventional semiconductor lasers. Surprisingly, this ultrafast operation relies on a short carrier spin relaxation time and a large anisotropy of the refractive index, both commonly viewed as detrimental in spintronics [3] and conventional lasers [4]. Our results overcome the key speed limitations of conventional directly modulated lasers and offer a prospect for the next generation of low-energy ultrafast optical communication.The global internet traffic will continue its dramatic increase in the near future [5]. Short-range and energy-efficient optical communication networks provide most of the communication bandwidth to secure the digital revolution. Key devices for high-speed optical interconnects, in particular in server farms, are current-driven intensity-modulated vertical-cavity surface-emitting lasers (VCSELs) [4]. Analogous to a driven damped harmonic oscillator, modulated lasers have a resonance frequency f R for the relaxation oscillations of the light intensity [6]. For higher frequencies the response decays and reaches half of its low-frequency value at f 3dB ≈ 1 + √ 2f R , which quantifies the usable frequency range [4]. In conventional VCSELs the modulation bandwidth is limited by the dynamics of the coupled carrier-photon system and parasitic as well as thermal effects. The current record is f 3dB = 34 GHz [7]. Common approaches to enhance the bandwidth rely on the expression f R = v g aS/τ p /(2π), where v g is the group velocity, a the differential gain, S the photon density, and τ p the * markus.lindemann@rub.de † nils.gerhardt@rub.de arXiv:1807.02820v1 [cond-mat.mes-hall]

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confidence: 99%

Ultrafast spin-lasers

Lindemann

Pusch

et al. 2019

Nature

186

134

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“…It is worth mentioning that for laser separation distances larger than those typically occurring in PICs or in cases where delays are intentionally introduced, such systems are described by delay-differential equations having a rich set of dynamical features [21][22][23][24].The introduction of topological characteristics in coupled lasers in terms of differential pumping and frequency detuning between the lasers [ Fig. 1(d)] enables the onchip implementation of a large set of key functionalities such as reconfigurable beam forming and steering [25], coherence tuning and enhanced phase-locking [26][27][28], localized syncrhonization [27,29], enhanced bandwidth and tailored modulation response [30,31] as well as existence of exceptional points allowing for ultra-sensitivity [32][33][34][35].In this work we consider the fundamental non-Hermitian optical meta-molecule consisting of two mutually coupled and differentially pumped semiconductor lasers as the basic reconfigurable oscillator element of a photonic integrated circuit exhibiting an extreme frequency tunability spanning over 100 GHz and controlled by minute changes of the electrically injected differential pumping. The latter is shown to control not only the frequency but also the shape of the underlying limit cycle providing a remarkable flexibility for the RF properties of the emited light beam.The time evolution of the electric fields and the number densities of two evanescently coupled diode lasers is governed by the following coupled single-mode rate equations for the amplitude of their normalized electric fields E 1 , E 2 , their phase difference θ and the normalized excess…”

mentioning

confidence: 99%

“…The introduction of topological characteristics in coupled lasers in terms of differential pumping and frequency detuning between the lasers [ Fig. 1(d)] enables the onchip implementation of a large set of key functionalities such as reconfigurable beam forming and steering [25], coherence tuning and enhanced phase-locking [26][27][28], localized syncrhonization [27,29], enhanced bandwidth and tailored modulation response [30,31] as well as existence of exceptional points allowing for ultra-sensitivity [32][33][34][35].…”

mentioning

confidence: 99%

“…In addition to the parameters of the corresponding phase-locked states from which they have emerged, the limit cycles are characterized by their frequencies f H and ratios R of the peak-to-peak electric field oscillation amplitudes that can be determined as the imaginary part of the eigenvalues with zero real part at the Hopf bifurcation point and the ratio of the first two components of the corresponding eigenvectors, respectively. In what follows we focus on a system with parameters values corresponding to recent experiments on coherently coupled phased photonic crystal vertical cavity lasers [30] as shown in Table I.…”

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confidence: 99%

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Radically tunable ultrafast photonic oscillators via differential pumping

Kominis

Bountis

Kovanis

2020

Journal of Applied Physics

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We present the controllability capabilities for the limit cycles of an extremely tunable photonic oscillator, consisting of two coupled semiconductor lasers. We show that this system supports stable limit cycles with frequencies ranging from a few to more than a hundred GHz that are characterized by a widely varying degree of asymmetry between the oscillations of the two lasers. These dyamical features are directly controllable via differential pumping as well as optical frequency detuning of the two lasers, suggesting a multi-functional oscillator for chip-scale radio-frequency photonics applications.Limit cycles are the fundamental ingredients of a wide variety of physical as well as man-made systems exhibiting characteristic self-sustained oscillations. Their existence is directly related to the interplay of two characteristic features that can be met in almost all realistic models, namely nonlinearity and dissipation. In contrast to oscillations of conservative nonlinear systems whose frequency is determined by the initial energy of the system, limit cycles have frequencies that are determined solely by the parameters of the system and often constitute global attractors to which the system evolves for any initial condition [1]. The existence of such robust limit cycles renders them crucial for the life itself, since they often occur in chemical and biological rhymes such as circadian oscillations [2-5], whose frequencies are determined by enviromental physical parameters. On the other hand, the existence of such limit cycles in manmade systems is crucially important for key technological applications such as time or frequency references [6,7] with their range of frequencies being controllable by the system parameters with significantly greater freedom in comparison to biological oscillators.Currently, there is intense interest in various implementations of ultrafast reconfigurable oscillators in systems and functional devices for next generation Photonic Integrated Circuits (PIC) [8,9] and RF photonics applications [10]. Due to the fact that single semiconductor lasers are not capable of supporting limit cycles, configurations based on optically coupled lasers have been proposed and intensively studied for more than four decades [11]. In this context, Optically Injected Lasers (OIL) corresponding to a one-way coupling in a master-slave configuration [ Fig. 1(a)] have been shown to support relatively tunable limit cycles [12][13][14][15]; however, the need for a bulky optical isolator prevents their on-chip integration [9] and significantly restricts their applications. The utilization of strong mutual coupling, corresponding to complicated configurations where a single electric field mode is amplified by two gain blocks, has been shown to result to a gain-lever mechanism [ Fig. 1(b)] allowing for significant bandwidth-enhancing [16,17]. The case of evanecently coupled diode lasers is shown to be the most promising for photonic integration [9] and also capable of supporting stable limit cycles [18][19][20]. Ho...

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“…Here α is the linewidth enhancement factor, Λ is the normalized coupling constant, P 1,2 are the normalized excess pumping rates, T is the ratio of carrier to photon lifetimes, and t is the time normalized to the photon lifetime τ p [3,9]. In the following, we consider parameter values corresponding to recent experiments on coherently coupled phased photonic crystal vertical cavity lasers [34] as shown in Table I. Under equal pumping (P 1 = P 2 = P 0 ), the phaselocked states of the system (1), are given by setting the time derivatives of the system equal to zero and their stability is determined by the eigenvalues of the Jacobian of the linearized system.…”

Section: Rate Equation Model and Symmetry-breaking Phase Lockingmentioning

confidence: 99%

Antiresonances and Ultrafast Resonances in a Twin Photonic Oscillator

et al. 2019

Self Cite

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We consider the properties of the small-signal modulation response of symmetry-breaking phaselocked states of twin coupled semiconductor lasers. The extended stability and the varying asymmetry of these modes allows for the introduction of a rich set of interesting modulation response features, such as sharp resonances and anti-resonance as well as efficient modulation at very high frequencies exceeding the free running relaxation frequencies by orders of magnitude.

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Modulation of Coherently Coupled Phased Photonic Crystal Vertical Cavity Laser Arrays

Cited by 55 publications

References 50 publications

Ultrafast spin-lasers

Ultrafast spin-lasers

Radically tunable ultrafast photonic oscillators via differential pumping

Antiresonances and Ultrafast Resonances in a Twin Photonic Oscillator

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