Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

EPJ Web of Conferences

Phase dynamics of two optically coupled InP lasers in a PIC for quantum random number generation

Berta Martínez-Pàmias, Miquel Rudé, Cristina Masoller

Published Jan 1, 2026• 0 citations
Publisher

Abstract

We present an experimental and numerical study of the probability distribution of interference pulses from two InP lasers in a photonic integrated circuit (PIC) operated in gain-switching mode through a square-wave signal that turns them on and off. Without laser coupling, the lasers’ phases are random due to quantum spontaneous emission noise, and their phase difference can be translated into a random intensity and exploited for quantum random number generation (QRNG). We analyze the coupling dynamics that lead to optical phase synchronization. Through a direct comparison between experiments and simulations, we demonstrate a clear correlation between laser coupling and the degradation of the randomness of the lasers’ optical phases, providing a better understanding of the operation and performance of the QRNG device.

DOI
10.1051/epjconf/202638904008

Related papers

Phase Synchronization Dynamics of Two Coupled Lasers for Quantum Random Number Generation

Berta Martínez-Pàmias, Miquel Rudé, Cristina Masoller

We performed an experimental and numerical study of an Indium Phosphide (InP) photonic integrated circuit (PIC) designed for quantum random number generation. We studied the dynamics of two weakly mutually coupled semiconductor lasers, and the transient evolution towards the synchronization of the lasers’ optical phases. By carefully adjusting the parameters of a rate-equation model, the simulated dynamics was found to be in qualitatively good agreement with the experimentally observed time traces. Our results allow us to better understand the transient evolution towards synchronization, and provide a foundation for the optimization of the system for photonic quantum random number generation.

International Conference on Transparent Optical Networks•Jul 6, 2025•0 citations

Phase synchronization dynamics of two mutually coupled InP lasers in a quantum entropy source

Berta Martínez-Pàmias, Miquel Rudé, Cristina Masoller

Quantum random number generators, at the core of digital trust infrastructures, rely on quantum entropy sources (QESs) to produce randomness from physical processes. The quantum origin certification of a QES requires a physical model compatible with the measured signal of the device. Here, we study Quside Technologies' phase-diffusion QES consisting of a photonic integrated circuit (PIC) that uses the interference of two indium phosphide (InP) lasers operated in gain-switching by simultaneously modulating their pump currents from below to above the threshold. This produces intensity pulses in each laser that have random optical phases due to quantum spontaneous emission. The lasers' intensities interfere via heterodyning, and from the interference signal a random bit is obtained per modulation cycle. While this system offers high scalability and compactness, residual coupling between the two lasers can induce phase synchronization, thus reducing its extractable entropy. Through experiments and simulations of a physical model based on coupled stochastic rate equations, we quantify this effect and link laser coupling to phase synchronization. We further derive an analytical model for the probability distribution of the measured interference intensity, enabling direct extraction of the quantum phase difference distribution and laying the groundwork for the QES optimization.

arXiv:2607.11806•Jul 13, 2026•0 citations

Phase synchronization dynamics of a mutually coupled laser system for quantum random number generation

Berta Martínez-Pàmias, Miquel Rudé, Cristina Masoller

We performed an experimental and numerical study of an Indium Phosphide photonic integrated circuit designed for quantum random number generation. We investigated the dynamics of two weakly mutually coupled semiconductor lasers and the transient evolution towards the synchronization of the lasers’ optical phases. The simulated dynamics with the experimentally adjusted parameters were found to be in qualitatively good agreement with the experimental time traces. The results provide a better understanding of the evolution towards synchronization and a foundation for the optimization of the photonic quantum random number generation system.

EPJ Web of Conferences•Jan 1, 2025•0 citations

Phase synchronization dynamics of a mutually coupled laser system for quantum random number generation

Berta Martínez-Pàmias, Miquel Rudé, Cristina Masoller

We performed an experimental and numerical study of an Indium Phosphide photonic integrated circuit designed for quantum random number generation. We investigated the dynamics of two weakly mutually coupled semiconductor lasers and the transient evolution towards the synchronization of the lasers’ optical phases. The simulated dynamics with the experimentally adjusted parameters were found to be in qualitatively good agreement with the experimental time traces. The results provide a better understanding of the evolution towards synchronization and a foundation for the optimization of the photonic quantum random number generation system.

•Sep 22, 2025•0 citations

Noise-Rejecting Photonic Integrated Circuit for Robust Quantum Random Number Generation

Peter Raymond Smith, Davide G. Marangon, T. K. Paraiso +2 more

Recent advancements in integrated photonics have shown great promise for the serial production of chip-scale quantum random number generators (QRNG). Considerable progress has been made towards developing fully on-chip QRNGs that exploit the interference of phase-randomized fields from two independent lasers. While a common alternative design, based on a single laser and interferometer, would further improve power consumption and ease of operation, monolithic integration of such a design has thus far faced challenges, including high losses and crosstalk. We solve these key challenges and report fast single-laser interferometric QRNGs integrated onto monolithic chips. By combining on-chip optical amplification with electronic common-mode rejection techniques, our photonic integrated circuits (PICs) stably convert the spontaneous emission phase noise of a diode laser into electronic pulses of high-contrast random intensity at GHz clock rates. Using real-time, hash-function-based randomness extraction, uniformly distributed, truly unpredictable random numbers are generated at a rate of 3 Gbps.

Optical Fiber Communication Conference•Aug 18, 2025•4 citations

Experimental study of a quantum random-number generator based on two independent lasers

Shi‐Hai Sun, Feihu Xu

A quantum random-number generator (QRNG) can produce true randomness by utilizing the inherent probabilistic nature of quantum mechanics. Recently, the spontaneous-emission quantum phase noise of the laser has been widely deployed for quantum random-number generation, due to its high rate, its low cost, and the feasibility of chip-scale integration. Here, we perform a comprehensive experimental study of a phase-noise-based QRNG with two independent lasers, each of which operates in either continuous-wave (CW) or pulsed mode. We implement the QRNG by operating the two lasers in three configurations, namely, CW + CW, CW + pulsed, and pulsed + pulsed, and demonstrate their trade-offs, strengths, and weaknesses.

arXiv:1712.01428•Physical Review A•Dec 14, 2017•21 citations
We present an experimental and numerical study of the probability distribution of interference pulses from two InP lasers in a photonic integrated circuit (PIC) operated in gain-switching mode through a square-wave signal that turns them on and off. Without laser coupling, the lasers’ phases are random due to quantum spontaneous emission noise, and their phase difference can be translated into a random intensity and exploited for quantum random number generation (QRNG). We analyze the coupling dynamics that lead to optical phase synchronization. Through a direct comparison between experiments and simulations, we demonstrate a clear correlation between laser coupling and the degradation of the randomness of the lasers’ optical phases, providing a better understanding of the operation and performance of the QRNG device.
We performed an experimental and numerical study of an Indium Phosphide (InP) photonic integrated circuit (PIC) designed for quantum random number generation. We studied the dynamics of two weakly mutually coupled semiconductor lasers, and the transient evolution towards the synchronization of the lasers’ optical phases. By carefully adjusting the parameters of a rate-equation model, the simulated dynamics was found to be in qualitatively good agreement with the experimentally observed time traces. Our results allow us to better understand the transient evolution towards synchronization, and provide a foundation for the optimization of the system for photonic quantum random number generation.
Quantum random number generators, at the core of digital trust infrastructures, rely on quantum entropy sources (QESs) to produce randomness from physical processes. The quantum origin certification of a QES requires a physical model compatible with the measured signal of the device. Here, we study Quside Technologies' phase-diffusion QES consisting of a photonic integrated circuit (PIC) that uses the interference of two indium phosphide (InP) lasers operated in gain-switching by simultaneously modulating their pump currents from below to above the threshold. This produces intensity pulses in each laser that have random optical phases due to quantum spontaneous emission. The lasers' intensities interfere via heterodyning, and from the interference signal a random bit is obtained per modulation cycle. While this system offers high scalability and compactness, residual coupling between the two lasers can induce phase synchronization, thus reducing its extractable entropy. Through experiments and simulations of a physical model based on coupled stochastic rate equations, we quantify this effect and link laser coupling to phase synchronization. We further derive an analytical model for the probability distribution of the measured interference intensity, enabling direct extraction of the quantum phase difference distribution and laying the groundwork for the QES optimization.
We performed an experimental and numerical study of an Indium Phosphide photonic integrated circuit designed for quantum random number generation. We investigated the dynamics of two weakly mutually coupled semiconductor lasers and the transient evolution towards the synchronization of the lasers’ optical phases. The simulated dynamics with the experimentally adjusted parameters were found to be in qualitatively good agreement with the experimental time traces. The results provide a better understanding of the evolution towards synchronization and a foundation for the optimization of the photonic quantum random number generation system.
We performed an experimental and numerical study of an Indium Phosphide photonic integrated circuit designed for quantum random number generation. We investigated the dynamics of two weakly mutually coupled semiconductor lasers and the transient evolution towards the synchronization of the lasers’ optical phases. The simulated dynamics with the experimentally adjusted parameters were found to be in qualitatively good agreement with the experimental time traces. The results provide a better understanding of the evolution towards synchronization and a foundation for the optimization of the photonic quantum random number generation system.
Recent advancements in integrated photonics have shown great promise for the serial production of chip-scale quantum random number generators (QRNG). Considerable progress has been made towards developing fully on-chip QRNGs that exploit the interference of phase-randomized fields from two independent lasers. While a common alternative design, based on a single laser and interferometer, would further improve power consumption and ease of operation, monolithic integration of such a design has thus far faced challenges, including high losses and crosstalk. We solve these key challenges and report fast single-laser interferometric QRNGs integrated onto monolithic chips. By combining on-chip optical amplification with electronic common-mode rejection techniques, our photonic integrated circuits (PICs) stably convert the spontaneous emission phase noise of a diode laser into electronic pulses of high-contrast random intensity at GHz clock rates. Using real-time, hash-function-based randomness extraction, uniformly distributed, truly unpredictable random numbers are generated at a rate of 3 Gbps.
A quantum random-number generator (QRNG) can produce true randomness by utilizing the inherent probabilistic nature of quantum mechanics. Recently, the spontaneous-emission quantum phase noise of the laser has been widely deployed for quantum random-number generation, due to its high rate, its low cost, and the feasibility of chip-scale integration. Here, we perform a comprehensive experimental study of a phase-noise-based QRNG with two independent lasers, each of which operates in either continuous-wave (CW) or pulsed mode. We implement the QRNG by operating the two lasers in three configurations, namely, CW + CW, CW + pulsed, and pulsed + pulsed, and demonstrate their trade-offs, strengths, and weaknesses.