Wavelength tuning of VCSELs via controlled strain.

Besides major advantages for telecommunication applications, vertical-cavity surface-emitting lasers (VCSELs) have attracted interest for their potential for neuro-inspired computing, frequency comb generation, or high-frequency spin oscillations. In the meantime, strain applied to the laser structure has been shown to have a significant impact on the laser emission properties such as the polarization dynamics or birefringence. In this work, we further explore the influence of strain on VCSELs and how this effect could be used to fine-tune the laser wavelength.

Clarifying the impact of dual optical feedback on semiconductor lasers through analysis of the effective feedback phase.

Time-delayed optical feedback is known to trigger a wide variety of complex dynamical behavior in semiconductor lasers. Adding a second optical feedback loop is naturally expected to further increase the complexity of the system and its dynamics, but due to interference between the two feedback arms, it was also quickly identified as a way to improve the laser stability. While these two aspects have already been investigated, the influence of the feedback phases, i.

Agile THz-range spectral multiplication of frequency combs using a multi-wavelength laser.

A breakthrough technology, on-chip frequency comb sources offer broadband combs while being compact, energy-efficient, and cost-effective solutions for various applications from lidar to telecommunications. Yet, these sources encounter a fundamental trade-off between controllability and bandwidth: broadband combs, generated in microresonators, lack free-spectral range or spectral envelope control, while combs generated with electro-optic modulators can be carefully tailored but are limited in bandwidth. Here, we overcome this trade-off through agile spectral multiplication of narrowband combs.

Mode-coupling effects in an optically-injected dual-wavelength laser.

Lasers designed to emit at multiple and controllable modes, or multi-wavelength lasers, have the potential to become key building blocks for future microwave photonic technologies. While many interesting schemes relying on optical injection have been proposed, the nonlinear mode coupling between different modes of a multi-wavelength laser and their dynamical behavior under optical injection remains vastly unexplored. Here, we experimentally and numerically study the effect of optical injection around the suppressed mode of a dual-wavelength laser and the resulting interactions with the dominant mode.

Impact of FBG feedback phase on laser dynamics.

Fiber Bragg gratings (FBGs) have been advantageously used to improve the chaotic properties of semiconductor lasers. Though these components are known to be highly sensitive to environmental conditions, feedback phase fluctuations are often neglected. In this work, we experimentally demonstrate that the small variations of the propagation time induced by a simple thermal tuning of the FBG are sufficient to induce significant changes of the laser behavior.

Chaotic time-delay signature suppression using quantum noise.

The time-delay signature (TDS) suppression of semiconductor lasers with external optical feedback is necessary to ensure the security of chaos-based secure communications. Here we numerically and experimentally demonstrate a technique to effectively suppress the TDS of chaotic lasers using quantum noise. The TDS and dynamical complexity are quantified using the autocorrelation function and normalized permutation entropy at the feedback delay time, respectively.

Optical Boolean chaos.

Boolean chaos is widely used in physical systems for its digital-like behavior and complex dynamics. However, electronic logic devices limit the bandwidth of Boolean chaos and its development. Based on an autonomous optical Boolean network, a method of generating optical Boolean chaos with 14 GHz bandwidth is proposed, exploring the physical mechanism of the chaos generated by the system and analyzing the influences of external parameters on the dynamic characteristics of the system.

Evaluating entropy rate of laser chaos and shot noise.

Evaluating entropy rate of high-dimensional chaos and shot noise from analog raw signals remains elusive and important in information security. We experimentally present an accurate assessment of entropy rate for physical process randomness. The entropy generation of optical-feedback laser chaos and physical randomness limit from shot noise are quantified and unambiguously discriminated using the growth rate of average permutation entropy value in memory time.

Relative intensity noise reduction in a dual-state quantum-dot laser by optical feedback.

We report a reduction of the relative intensity noise (RIN) in a dual-state emitting quantum-dot laser subject to the state-selective optical feedback on the ground state and excited state. Numerically, we map the evolution of the RIN for variations of the optical feedback phases for both states. We report important differences in the impact of the feedback when applied to the ground or excited state, and observe regimes for which a significant reduction in RIN is achieved.

Synchronization of polarization chaos from a free-running VCSEL.

We theoretically demonstrate the possibility to synchronize polarization chaos generated by a free-running vertical-cavity surface-emitting laser (VCSEL). We highlight two distinct synchronization regimes: 1) a high-quality synchronization regime where all polarization modes and total intensity are synchronized, which shows good robustness against parameter mismatch, and 2) a "slow time-scale" synchronization where the slower part of the dynamics-that is, the random-like hopping between the two scrolls of the chaotic attractor-synchronizes while the faster oscillations remain unsynchronized.

Energy exchange between modes in a multimode two-color quantum dot laser with optical feedback.

We investigate experimentally and theoretically the multimode dynamics of a two-color quantum dot laser subject to time-delayed optical feedback. We unveil energy exchanges between the longitudinal modes of the excited state triggered by variations of the feedback phase, and observe that the modal competition between longitudinal modes appears independently within the ground state and excited state emission. These features are accurately reproduced with a quantum dot laser model extended to take into account multiple modes for both ground and excited states.

Noise induced stabilization of chaotic free-running laser diode.

In this paper, we investigate theoretically the stabilization of a free-running vertical-cavity surface-emitting laser exhibiting polarization chaos dynamics. We report the existence of a boundary isolating the chaotic attractor on one side and a steady-state on the other side and identify the unstable periodic orbit playing the role of separatrix. In addition, we highlight a small range of parameters where the chaotic attractor passes through this boundary, and therefore where chaos only appears as a transient behaviour.

Asymmetric dwell-time statistics of polarization chaos from free-running VCSEL.

We experimentally report on asymmetric dwell-time statistics of polarization chaos dynamics generated from free-running vertical-cavity surface-emitting lasers (VCSELs). Theoretically, we explain this behavior by introducing a misalignment between the phase and amplitude anisotropy within the spin-flip model for VCSELs. It induces an asymmetry in the VCSEL polarization behavior which is then responsible for significant changes in the statistics of the chaotic mode-hopping with an increase in the average residence time and an inversion of the dominant mode.