© 2026 Aqora Quantum S.A.S.

Terms Privacy Legal Notice

Anais de XXXV Simpósio Brasileiro de Telecomunicações e Processamento de Sinais

Optical transmission of frequency-coded quantum bits with WDM synchronization

Thiago Ferreira da Silva, Jean Pierre von der Weid

Published Jan 1, 2008• 5 citations

Abstract

Quantum-key distribution enables absolutely secure communication between two parts, making them able to share a secret that will be used in the posterior message encryption.Here we shall report the experimental implementation of an optical qubits transmission system compatible with the BB84 protocol.Photons are prepared and measured by a double-modulation process according with the relative phase of a wavelength-division multiplexed synchronized radiofrequency signal, in the way that the qubits are coded in the optical sidebands.A filtering scheme is applied to further sidebands selection, delivering the qubits to the single-photon detector.

DOI: 10.14209/sbrt.2008.42879

Related papers

Quantum key distribution using transverse spin wave-optical interactions

Pradeep K Kumar, Anil Prabhakar

We describe a frequency-coded scheme to implement the BB84 quantum key distribution protocol using spin wave (SW)-optical interactions. The interaction of SWs with optical coherent states allows TE↔TM mode conversion with simultaneous change of frequency and polarization while introducing a phase difference between the two modes. To implement the BB84 protocol, key bits are encoded as relative phases between the TE and TM modes. The proposed scheme offers a higher key rate, due to a modulation frequency as high as 25 GHz, which also relaxes the specifications on the optical filter at the receiver. In addition, SW-optical interactions yield the added security of truly single-sideband modulation.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Feb 10, 2011•0 citations

Concepts, components and implementations for quantum key distribution over optical fibers

Nino Walenta

Quantum key distribution is an application of quantum physics that allows two distant partners to securely distribute shared random secrets which they can use for secure message encryption, authentication or other communication tasks. In this thesis, I study and implement several concepts, protocols and their components, in particular single photon detectors. I evaluate its compatibility with fiber infrastructures with the aim to improve applicability, performance and profitability of quantum key distribution in different scenarios. I present superconducting single photon detectors implemented for long distance quantum communication, as well as semiconductor detectors employing rapid sine gating schemes. Wavelength-multiplexing of quantum and classical communication channels is demonstrated to stabilize a polarization-encoded quantum channel against birefringence fluctuations, and to realize quantum and encrypted communication over one fiber. An implementation of the coherent one-way protocol is presented which features a hardware distillation engine, wavelength-multiplexing, and an analysis of finite key effects and authentication costs.

•Jan 1, 2013•3 citations

Fast Quantum Cryptography System Using Single Photon Communication

Akihisa Tomita, Akio Tajima

Quantum Key Distribution (QKD) systems based on single photon transmission can generate unconditionally secure common key between remote users. Improvement of QKD performance, particularly on key generation rate, has been required to meet current network traffic. High key generation rate is realized by increasing photon detection rate and by reducing error rate. Therefore, a high-speed QKD system should be equipped with low loss receivers with high visibility, highly efficient photon detectors with small dark count probability, and a stable clock synchronization system with low stray light to the quantum signals. A solution for these issues are given by employing planar lightwave circuit interferometers, single photon detection circuits and modules, and clock synchronization based on Wavelength Division Multiplexing (WDM) technique.

The Review of Laser Engineering•Jan 1, 2008•0 citations

Multidimensional Quantum Key Distribution with Single Side Pulse and Single Side Band Modulation Multiplexing

O.L. Guerreau

Quantum Cryptography enables secret distribution between remotes parties where classical communications fail. The proposed technique uses optical signal modulation to encode information with relative phase difference between frequency separated signals. The single side band detection scheme (SSB) enables efficient secret key distribution. The system security is guaranteed with a strong reference protocol. One can use a fainted laser source without security breach for any distance. A second proposed technique uses relative phase difference between time separated pulses. The single side pulse detection scheme (SSP) enables efficient secret key distribution and benefits the same security features as the SSB system. Both SSP and SSB may be multiplexed to increase the secure bit rate. The maximizing initial average energy is then one photon per pulse. The implemented SSB protocol includes an autocompensation system for the optical path fluctuations that make the system robust over long time periods.

•Nov 22, 2005•1 citation

Implementation of Quantum Key Distribution for Secure data transmission in Optical Communication

S. Krithiga, Ajay V, R Manoojitth +1 more

Quantum Key Distribution (QKD) is a potential defense against future quantum attacks that can break traditional encryption algorithms, such as RSA and ECC. The current work is based on the development of the BB84 protocol with the features of utilizing quantum mechanics and eavesdropping detection through signal disturbance. A simulation of the BB84 protocol was built using polarization encoding over a 10 km single-mode optical fiber using OptiSystem software. The system consists of standard telecom equipment, such as a continuous wave laser at a frequency of 193.1 THz, polarization controllers, and single-photon detectors. Both secure and insecure cases were simulated, where an attacker (Eve) had used an intercept-resend attack. The outcome showed significant Bit Error Rate (BER) and Quantum Bit Error Rate (QBER) increases during attacks, thus proving the protocol's vulnerability to interference. In addition, a special intrusion detection system based on BER was used to identify such anomalies in real-time. The simulation illustrates the feasibility of using QKD in today's optical networks to secure communications.

International Conference on Emerging Research in Electronics, Computer Science and Technology (ICERECT)•Sep 12, 2025•0 citations

Experimental multiplexing of quantum key distribution with classical optical communication

Liujun Wang, Luo-Kan Chen, Lei Ju +6 more

We demonstrate the realization of quantum key distribution (QKD) when combined with classical optical communication, and synchronous signals within a single optical fiber. In the experiment, the classical communication sources use Fabry-Pérot (FP) lasers, which are implemented extensively in optical access networks. To perform QKD, multistage band-stop filtering techniques are developed, and a wavelength-division multiplexing scheme is designed for the multi-longitudinal-mode FP lasers. We have managed to maintain sufficient isolation among the quantum channel, the synchronous channel and the classical channels to guarantee good QKD performance. Finally, the quantum bit error rate remains below a level of 2% across the entire practical application range. The proposed multiplexing scheme can ensure low classical light loss, and enables QKD over fiber lengths of up to 45 km simultaneously when the fibers are populated with bidirectional FP laser communications. Our demonstration paves the way for application of QKD to current optical access networks, where FP lasers are widely used by the end users.

Applied Physics Letters•Feb 23, 2015•64 citations

Quantum-key distribution enables absolutely secure communication between two parts, making them able to share a secret that will be used in the posterior message encryption.Here we shall report the experimental implementation of an optical qubits transmission system compatible with the BB84 protocol.Photons are prepared and measured by a double-modulation process according with the relative phase of a wavelength-division multiplexed synchronized radiofrequency signal, in the way that the qubits are coded in the optical sidebands.A filtering scheme is applied to further sidebands selection, delivering the qubits to the single-photon detector.

We describe a frequency-coded scheme to implement the BB84 quantum key distribution protocol using spin wave (SW)-optical interactions. The interaction of SWs with optical coherent states allows TE↔TM mode conversion with simultaneous change of frequency and polarization while introducing a phase difference between the two modes. To implement the BB84 protocol, key bits are encoded as relative phases between the TE and TM modes. The proposed scheme offers a higher key rate, due to a modulation frequency as high as 25 GHz, which also relaxes the specifications on the optical filter at the receiver. In addition, SW-optical interactions yield the added security of truly single-sideband modulation.

Quantum key distribution is an application of quantum physics that allows two distant partners to securely distribute shared random secrets which they can use for secure message encryption, authentication or other communication tasks. In this thesis, I study and implement several concepts, protocols and their components, in particular single photon detectors. I evaluate its compatibility with fiber infrastructures with the aim to improve applicability, performance and profitability of quantum key distribution in different scenarios. I present superconducting single photon detectors implemented for long distance quantum communication, as well as semiconductor detectors employing rapid sine gating schemes. Wavelength-multiplexing of quantum and classical communication channels is demonstrated to stabilize a polarization-encoded quantum channel against birefringence fluctuations, and to realize quantum and encrypted communication over one fiber. An implementation of the coherent one-way protocol is presented which features a hardware distillation engine, wavelength-multiplexing, and an analysis of finite key effects and authentication costs.

Quantum Key Distribution (QKD) systems based on single photon transmission can generate unconditionally secure common key between remote users. Improvement of QKD performance, particularly on key generation rate, has been required to meet current network traffic. High key generation rate is realized by increasing photon detection rate and by reducing error rate. Therefore, a high-speed QKD system should be equipped with low loss receivers with high visibility, highly efficient photon detectors with small dark count probability, and a stable clock synchronization system with low stray light to the quantum signals. A solution for these issues are given by employing planar lightwave circuit interferometers, single photon detection circuits and modules, and clock synchronization based on Wavelength Division Multiplexing (WDM) technique.

Quantum Cryptography enables secret distribution between remotes parties where classical communications fail. The proposed technique uses optical signal modulation to encode information with relative phase difference between frequency separated signals. The single side band detection scheme (SSB) enables efficient secret key distribution. The system security is guaranteed with a strong reference protocol. One can use a fainted laser source without security breach for any distance. A second proposed technique uses relative phase difference between time separated pulses. The single side pulse detection scheme (SSP) enables efficient secret key distribution and benefits the same security features as the SSB system. Both SSP and SSB may be multiplexed to increase the secure bit rate. The maximizing initial average energy is then one photon per pulse. The implemented SSB protocol includes an autocompensation system for the optical path fluctuations that make the system robust over long time periods.

Quantum Key Distribution (QKD) is a potential defense against future quantum attacks that can break traditional encryption algorithms, such as RSA and ECC. The current work is based on the development of the BB84 protocol with the features of utilizing quantum mechanics and eavesdropping detection through signal disturbance. A simulation of the BB84 protocol was built using polarization encoding over a 10 km single-mode optical fiber using OptiSystem software. The system consists of standard telecom equipment, such as a continuous wave laser at a frequency of 193.1 THz, polarization controllers, and single-photon detectors. Both secure and insecure cases were simulated, where an attacker (Eve) had used an intercept-resend attack. The outcome showed significant Bit Error Rate (BER) and Quantum Bit Error Rate (QBER) increases during attacks, thus proving the protocol's vulnerability to interference. In addition, a special intrusion detection system based on BER was used to identify such anomalies in real-time. The simulation illustrates the feasibility of using QKD in today's optical networks to secure communications.

We demonstrate the realization of quantum key distribution (QKD) when combined with classical optical communication, and synchronous signals within a single optical fiber. In the experiment, the classical communication sources use Fabry-Pérot (FP) lasers, which are implemented extensively in optical access networks. To perform QKD, multistage band-stop filtering techniques are developed, and a wavelength-division multiplexing scheme is designed for the multi-longitudinal-mode FP lasers. We have managed to maintain sufficient isolation among the quantum channel, the synchronous channel and the classical channels to guarantee good QKD performance. Finally, the quantum bit error rate remains below a level of 2% across the entire practical application range. The proposed multiplexing scheme can ensure low classical light loss, and enables QKD over fiber lengths of up to 45 km simultaneously when the fibers are populated with bidirectional FP laser communications. Our demonstration paves the way for application of QKD to current optical access networks, where FP lasers are widely used by the end users.