© 2026 Aqora Quantum S.A.S.

Terms Privacy Legal Notice

Optical Engineering

Implementing and testing a fiber-optic polarization-based intrusion detection system

Rasha El Hajj, Gregory Macdonald, Pramode K. Verma, Robert C. Huck

Published Sep 11, 2015• 8 citations

Abstract

We describe a layer-1-based intrusion detection system for fiber-optic–based networks. Layer-1-based intrusion detection represents a significant elevation in security as it prohibits an adversary from obtaining information in the first place (no cryptanalysis is possible). We describe the experimental setup of the intrusion detection system, which is based on monitoring the behavior of certain attributes of light both in unperturbed and perturbed optical fiber links. The system was tested with optical fiber links of various lengths and types, under different environmental conditions, and under changes in fiber geometry similar to what is experienced during tapping activity. Comparison of the results for perturbed and unperturbed links has shown that the state of polarization is more sensitive to intrusion activity than the degree of polarization or power of the received light. The testing was conducted in a simulated telecommunication network environment that included both underground and aerial links. The links were monitored for intrusion activity. Attempts to tap the link were easily detected with no apparent degradation in the visual quality of the real-time surveillance video.

DOI: 10.1117/1.oe.54.9.096107

Related papers

Limits of intrusion detection systems in a gigabit optical link

Abrar Salim, Saul S. Carroll, Javid Atai

We systematically investigate the capabilities of a commercial intrusion detection system for a gigabit optical Ethernet network. It is found that the location of the tap and the amount of light tapped out are key factors in being able to successfully intercept the data. It is also shown, for the first time, that there is a region within the plane of distance from the transmitter versus power penalty where the link can be tapped and the data can be extracted successfully without the intrusion being detected.

Optical Engineering•Apr 1, 2010•3 citations

Intrusion detection in optical fiber link: A novel technique

Sudad S. Ahmed

Because of the complexity of the observation of the eavesdropping process in optical fiber link, a new technique is suggested. A WDM is utilized as a part of optical fiber intrusion detection system. The implemented setup is capable to observe eavesdropping soon. The PC unit supports the system and it offers a suitable tool to observe or detect the leakage information. The minimum detectable attenuation value due to the intrusion is about (0.04 dB) while the optical power leakage is about 0.1 dB. Keywords: Intrusion, optical link, detection, eavesdropping.

Indian Journal of Science and Technology•Dec 20, 2010•1 citation

Fiber Tapping in Optical Networks: Attack Techniques, Detection, and Mitigation

Krzysztof Borzycki, Mirosław Klinkowski

Initially considered secure against interception, fiber-optic networks were subsequently found susceptible to covert tapping, although such attacks require different coupling mechanisms and components than those used for twisted pair and coaxial cables. Fiber-optic networks carry the majority of data and voice traffic worldwide, including backhaul and fronthaul traffic in 4G and 5G radio networks, connections between data centers, and submarine cable systems. Consequently, physical access to fibers for interception has attracted the attention of intelligence agencies and industrial spies. This vulnerability is facilitated by the fact that single-mode optical fibers (SMFs) used in telecommunication networks have evolved relatively little over the last 40 years. Fibers of substantially different designs—anti-resonant hollow core fibers (HCF) and multi-core fibers (MCF)—made their commercial debut around 2023, and their susceptibility to tapping may differ substantially from that of conventional SMFs. New promising fiber monitoring techniques based on polarization measurements have also been demonstrated recently. While established tapping techniques remain feasible for conventional fibers, new fiber designs and monitoring technologies can make covert interception difficult. This review examines physical fiber tapping techniques and their practical feasibility, with particular emphasis on optical power constraints, introduced loss, detectability, and implementation limitations. It also reviews prevention and monitoring approaches, including optical time-domain reflectometry, received-power monitoring, and state-of-polarization (SOP) monitoring, and provides a prospective engineering assessment of the susceptibility of MCFs and HCFs to physical tapping.

Photonics•Oct 15, 2026•0 citations

Testing of Four Channel Stokes Polarimeter for intrusion detection in Quantum Key Distribution systems

Estera Pawlikowska, M. Życzkowski, Anna Pakuła +1 more

We present the implementation of the Four-Channel Stokes Polarimeter for continuous monitoring of the state of polarization of light in QKD system, to detect disturbance of the fiber link integrity in the single photon regime.

International Conference on Optical Fiber Sensors (OFS)•Jan 1, 2023•1 citation

Optical fiber tapping: Methods and precautions

M. Zafar Iqbal, Habib Fathallah, Nezih Belhadj

Optical fiber communication is not as secure as generally perceived. There are a number of known methods of extracting or injecting information into a fiber link, while avoiding detection. Few incidents have been reported as a successfully tapped fiber is difficult to detect. In this paper we highlight a number of known fiber tapping methods. We report simulation of optical characteristics of a fiber being tapped by `bend' method and proof of concept with physical experiment. We also presented visualized scenarios in which a resourceful eavesdropper can compromise security of a fiber link with existing technologies. Some measures to prevent fiber tapping or to nullify the significance of information tapped from fiber were also discussed.

International Symposium on High-capacity Optical Networks and Enabling Technologies•Dec 1, 2011•77 citations

Secured optical fiber communication using polarization restoration technique and channel characterization

Nikhil Punekar, Bhagyashri Darunkar, Pramode K. Verma

Optical fiber channels are used as media to transfer the information globally. This paper presents an implementation of a novel procedure using which a secured communication between two parties can be carried out using polarized beam of light over an optical fiber. The paper presents the experimental results obtained of the procedure in the lab environment and a security analysis of the same. It is observed that polarization state of a light pulse cannot be retained as it travels over an optical fiber because of the birefringence phenomenon. Multiple environmental factors such as pressure, vibration, temperature, etc. also add a non-linearity to the birefringence of an optical fiber leading towards an unpredictable polarization state changes over the course of an optical fiber. The proposed procedure helps the receiving party to successfully retrieve the data in the form of a polarization state transmitted by the sending party without having any knowledge about the state of polarization at the transmitting end. The paper also explains an added layer of security the procedure provides to the communicating parties to make it difficult for an adversary to fetch the data being transferred. The proposed system does not depend on the wavelength of the light being used, nor does it depend upon the type of the optical fiber used for the communication. Using this procedure, multiple bits of secured information can be sent over an optical fiber in a single polarized pulse and retrieved at the receiving end, also known as Polarization Shift Keying.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Feb 13, 2016•1 citation

We describe a layer-1-based intrusion detection system for fiber-optic–based networks. Layer-1-based intrusion detection represents a significant elevation in security as it prohibits an adversary from obtaining information in the first place (no cryptanalysis is possible). We describe the experimental setup of the intrusion detection system, which is based on monitoring the behavior of certain attributes of light both in unperturbed and perturbed optical fiber links. The system was tested with optical fiber links of various lengths and types, under different environmental conditions, and under changes in fiber geometry similar to what is experienced during tapping activity. Comparison of the results for perturbed and unperturbed links has shown that the state of polarization is more sensitive to intrusion activity than the degree of polarization or power of the received light. The testing was conducted in a simulated telecommunication network environment that included both underground and aerial links. The links were monitored for intrusion activity. Attempts to tap the link were easily detected with no apparent degradation in the visual quality of the real-time surveillance video.

We systematically investigate the capabilities of a commercial intrusion detection system for a gigabit optical Ethernet network. It is found that the location of the tap and the amount of light tapped out are key factors in being able to successfully intercept the data. It is also shown, for the first time, that there is a region within the plane of distance from the transmitter versus power penalty where the link can be tapped and the data can be extracted successfully without the intrusion being detected.

Because of the complexity of the observation of the eavesdropping process in optical fiber link, a new technique is suggested. A WDM is utilized as a part of optical fiber intrusion detection system. The implemented setup is capable to observe eavesdropping soon. The PC unit supports the system and it offers a suitable tool to observe or detect the leakage information. The minimum detectable attenuation value due to the intrusion is about (0.04 dB) while the optical power leakage is about 0.1 dB. Keywords: Intrusion, optical link, detection, eavesdropping.

Initially considered secure against interception, fiber-optic networks were subsequently found susceptible to covert tapping, although such attacks require different coupling mechanisms and components than those used for twisted pair and coaxial cables. Fiber-optic networks carry the majority of data and voice traffic worldwide, including backhaul and fronthaul traffic in 4G and 5G radio networks, connections between data centers, and submarine cable systems. Consequently, physical access to fibers for interception has attracted the attention of intelligence agencies and industrial spies. This vulnerability is facilitated by the fact that single-mode optical fibers (SMFs) used in telecommunication networks have evolved relatively little over the last 40 years. Fibers of substantially different designs—anti-resonant hollow core fibers (HCF) and multi-core fibers (MCF)—made their commercial debut around 2023, and their susceptibility to tapping may differ substantially from that of conventional SMFs. New promising fiber monitoring techniques based on polarization measurements have also been demonstrated recently. While established tapping techniques remain feasible for conventional fibers, new fiber designs and monitoring technologies can make covert interception difficult. This review examines physical fiber tapping techniques and their practical feasibility, with particular emphasis on optical power constraints, introduced loss, detectability, and implementation limitations. It also reviews prevention and monitoring approaches, including optical time-domain reflectometry, received-power monitoring, and state-of-polarization (SOP) monitoring, and provides a prospective engineering assessment of the susceptibility of MCFs and HCFs to physical tapping.

Optical fiber communication is not as secure as generally perceived. There are a number of known methods of extracting or injecting information into a fiber link, while avoiding detection. Few incidents have been reported as a successfully tapped fiber is difficult to detect. In this paper we highlight a number of known fiber tapping methods. We report simulation of optical characteristics of a fiber being tapped by `bend' method and proof of concept with physical experiment. We also presented visualized scenarios in which a resourceful eavesdropper can compromise security of a fiber link with existing technologies. Some measures to prevent fiber tapping or to nullify the significance of information tapped from fiber were also discussed.

Optical fiber channels are used as media to transfer the information globally. This paper presents an implementation of a novel procedure using which a secured communication between two parties can be carried out using polarized beam of light over an optical fiber. The paper presents the experimental results obtained of the procedure in the lab environment and a security analysis of the same. It is observed that polarization state of a light pulse cannot be retained as it travels over an optical fiber because of the birefringence phenomenon. Multiple environmental factors such as pressure, vibration, temperature, etc. also add a non-linearity to the birefringence of an optical fiber leading towards an unpredictable polarization state changes over the course of an optical fiber. The proposed procedure helps the receiving party to successfully retrieve the data in the form of a polarization state transmitted by the sending party without having any knowledge about the state of polarization at the transmitting end. The paper also explains an added layer of security the procedure provides to the communicating parties to make it difficult for an adversary to fetch the data being transferred. The proposed system does not depend on the wavelength of the light being used, nor does it depend upon the type of the optical fiber used for the communication. Using this procedure, multiple bits of secured information can be sent over an optical fiber in a single polarized pulse and retrieved at the receiving end, also known as Polarization Shift Keying.