Abstract Photon superbunching, with second-order coherence far beyond the Gaussian thermal limit, is a valuable resource for quantum optics and correlation-based imaging. However, existing sources often rely on fragile platforms, inefficient nonlinear conversion, or mechanically complex architectures. Here, we demonstrate the first highly stable, fully fiber-integrated superbunched random fiber laser that provides a broadly tunable source of giant photon bunching. We establish a cooperative linear–nonlinear mechanism in which Rayleigh-scattering-mediated diffusion provides distributed random feedback, while cascaded stimulated Brillouin scattering and quasi-phase-matched four-wave mixing amplify and redistribute stochastic intensity fluctuations across a spectral comb. This enables continuous tuning of g (2) (0) from approximately 1 to 28 via tailored modulation of linear diffusion strength and nonlinear coupling magnitude. Moreover, by combining photon-correlation measurements with Parisi-overlap analysis, we reveal an inverse correlation between disorder-induced photonic phase evolution and microscopic photon bunching, bridging macroscopic disordered-cavity dynamics and high-order photon statistics. Furthermore, we demonstrate that strongly superbunched light enables temporal ghost imaging with comparable reconstruction fidelity while requiring more than an order-of-magnitude fewer realizations than weakly bunched light. Together, these results establish a fiber-integrated route to engineering giant photon superbunching and high-order light statistics for correlation-based photonic technologies.
Abstract Photon superbunching, with second-order coherence far beyond the Gaussian thermal limit, is a valuable resource for quantum optics and correlation-based imaging. However, existing sources often rely on fragile platforms, inefficient nonlinear conversion, or mechanically complex architectures. Here, we demonstrate the first highly stable, fully fiber-integrated superbunched random fiber laser that provides a broadly tunable source of giant photon bunching. We establish a cooperative linear–nonlinear mechanism in which Rayleigh-scattering-mediated diffusion provides distributed random feedback, while cascaded stimulated Brillouin scattering and quasi-phase-matched four-wave mixing amplify and redistribute stochastic intensity fluctuations across a spectral comb. This enables continuous tuning of g (2) (0) from approximately 1 to 28 via tailored modulation of linear diffusion strength and nonlinear coupling magnitude. Moreover, by combining photon-correlation measurements with Parisi-overlap analysis, we reveal an inverse correlation between disorder-induced photonic phase evolution and microscopic photon bunching, bridging macroscopic disordered-cavity dynamics and high-order photon statistics. Furthermore, we demonstrate that strongly superbunched light enables temporal ghost imaging with comparable reconstruction fidelity while requiring more than an order-of-magnitude fewer realizations than weakly bunched light. Together, these results establish a fiber-integrated route to engineering giant photon superbunching and high-order light statistics for correlation-based photonic technologies.
Photon superbunching, distinguished by second-order coherence values far exceeding the Gaussian thermal limit, represents a highly desirable resource for quantum optics and correlation-based imaging technologies. However, existing approaches typically rely on fragile experimental platforms, inefficient nonlinear conversion processes, or mechanically complex optical architectures. Here, we demonstrate a fully fiber-integrated superbunched random fiber laser (SRFL) in which intrinsic Rayleigh scattering cooperatively interacts with cascaded stimulated Brillouin scattering and quasi-phase-matched four-wave mixing to tailor extreme photon statistics. The SRFL generates a multi-wavelength comb, in which individual spectral components exhibit widely tunable photon bunching, with the second-order coherence g(2)(0) continuously controlled from ~1 to ~26 by tuning the pump power, spectral order and diffusion length. Moreover, we establish a direct correlation between photonic phase transitions (quantified by the Parisi overlap order parameter) and the emergence of superbunching, thereby bridging macroscopic disorder physics and microscopic photon statistics. Finally, we employ the superbunched emission for temporal ghost imaging, realizing high-fidelity temporal object reconstruction with a substantial reduction in required ensemble averaging. These findings validate random fiber lasers as a robust, scalable, and integrated platform for generating extreme photon statistics and unlock new avenues for correlation-enhanced photonic sensing and quantum optics investigations in complex photonic systems.
We proposed to boost the photon bunching effect of classical light via a modified Fabry-Pérot cavity with one of the cavity mirrors being replaced by a spatial light modulator, through which multiple independent transverse modulations, each was to encode independently spatially correlated phase on the wave front of the light field, was cascaded in sequence in the longitudinal propagation direction in the cavity. The two-photon bunching peak and the three-photon bunching peak of the generated superbunching light field were measured to be 36.9±2.0 and (2.46±0.12)×103, respectively, which, as compared to those of thermal light, were improved by one-order and three-order of magnitude, respectively. Correspondingly, the ghost image visibility reconstructed with the superbunching light was demonstrated experimentally to be improved by ∼40 times as compared to that with the pseudo-thermal light. Such classical superbunching light field is of essential importance not only for fundamental physics but also for potential applications such as correlated imaging, ghost interference and nonlinear optics.
Non-classical light sources emitting bundles of N-photons with strong correlation represent versatile resources of interdisciplinary importance with applications ranging from fundamental tests of quantum mechanics to quantum information processing. Yet, high-order correlations, gN(0),quantifying photon correlation, are still limited to hundreds. Here, we report the generation of a super-bunching light source in photonic crystal fiber with g2(0) reaching 5.86*104 and g5(0) up to 2.72*108, through measuring its photon number probability distributions. under giant g2(0) values, the super-bunching light source presents upturned-tail photon distributions and ubiquitous extreme multi-photon events, where 31 photons from a single light pulse at a mean of 1.99*10-4 photons per pulse have been determined. The probability of this extreme event has been enhanced by 10139 folds compared to a coherent laser with Poissonian distribution. By varying the power of the pumping laser, both photon number distributions and corresponding high-order correlations of this light source can be substantially tailored from Poissonian to super-bunching distributions. These phenomena are attributed to the synchronized nonlinear interactions in photonic crystal fibers pumping by bright squeezed light, and the theoretical simulations agree well with the experimental results. Our research showcases the ability to achieve non-classical light sources with giant high-order correlations and extreme multi-photon events, paving the way for high-order correlation imaging, extreme nonlinear optical effects, quantum information processing, and exploring light-matter interactions with multi-photon physics.
Photon superbunching, which occurs when the second-order correlation satisfies g(2)>2, is typically associated with strong optical nonlinearities or collective multi-photon emission processes. We predict that extreme superbunching can also arise in systems of weakly-nonlinear photonic cavities, via the creation of a squeezed vacuum through interference engineering by fine-tuning inter-cavity couplings and drive parameters. We present numerical calculations indicating that a system of four photonic resonators containing representative Kerr media can achieve g(2)(0)=135 with a 80kHz emission rate. Unlike earlier superbunching schemes, this mechanism is highly compatible with integrated photonic platforms constructed using conventional optical media.
Since Hanbury Brown and Twiss revealed the photon bunching effect of a thermal light source in 1956, almost all studies in correlation optics have been based on light’s intensity fluctuation, regardless of fact that the polarization fluctuation is a basic attribute of natural light. In this work, we uncover the veil of the polarization fluctuation and corresponding photon correlations by proposing a new light source model, termed pseudo-natural light, embodying both intensity and polarization fluctuations. Unexpectedly, the strong antibunching and superbunching effects can be simultaneously realized in such a new source, whose second-order correlation coefficient g ( 2 ) can be continuously modulated across 1. For the symmetric Bernoulli distribution of the polarization fluctuation, particularly, g ( 2 ) can be in principle from 0 to unlimitedly large. In pseudo-natural light, while the bunching effects of both intensity and polarization fluctuations enhance the bunching to superbunching photon correlation, the antibunching correlation of the polarization fluctuation can also be extracted through the procedure of division operation in the experiment. The antibunching effect and the combination with the bunching one will arouse new applications in quantum imaging. As heuristic examples, we carry out high-quality positive or negative ghost imaging, and devise high-efficiency polarization-sensitive and edge-enhanced imaging. This work, therefore, sheds light on the development of multiple and broad correlation functions for natural light.
Correlations existing between spectral components in multi-wavelength lasers have been the key challenge that hinders these laser sources from being developed to chaotic comb entropy sources for parallel random bit generation. Herein, spectrotemporally uncorrelated multi-order Stokes/anti-Stokes emissions are achieved by cooperatively exploiting nonlinear optical processes including cascaded stimulated Brillouin scattering and quasi-phase-matched four-wave mixing in a Brillouin random fiber laser. Chaotic instabilities induced by random mode resonance are enhanced and disorderly redistributed among different lasing lines through complex nonlinear optical interactions, which comprehensively releases the inherent correlation among multiple Stokes/anti-Stokes emission lines, realizing a chaotic frequency comb with multiple spectrotemporally uncorrelated channels. Parallel fast random bit generation is fulfilled with 31 channels, single-channel bit rate of 35-Gbps and total bit rate of 1.085-Tbps. National Institute of Standards and Technology statistic tests verify the randomness of generated bit streams. This work, in a simple and efficient way, breaks the correlation barrier for utilizing multi-wavelength laser to achieve high-quality spectrotemporally uncorrelated chaotic laser source, opening new avenues for achieving greatly accelerated random bit generation through parallelization and potentially revolutionizing the current architecture of secure communication and high-performance computation.