Passive Fiber Optic Components Research Articles

Risk Analysis of Countermeasures Against the Trojan-Horse Attacks on Quantum Key Distribution Systems in 1260–1650 nm Spectral Range

The results of investigation of the spectral characteristics of some passive fiber-optic components, such as optical isolators, circulators, spectral filters and multiplexers, used in quantum key distribution (QKD) systems and contributing to the protection of QKD system from active optical probing attacks are presented. An assessment of the required degree of isolation is also given, which ensures reliable protection of the QKD system against Trojan-horse attacks under the most stringent conditions for legitimate users. Based on the formulated requirements and measurement results, the effectiveness of protection using the investigated passive insulating components is analyzed. Using the example of calculating the insulation for the QKD system scheme presented in the work, the achievement of the required level of isolation (150 dB) in the entire considered spectral range is shown.

Анализ эффективности методов защиты от атак активного оптического зондирования на волоконные системы квантового распределения ключей в спектральном диапазоне 1260-1650 nm

In this paper, the results of research of spectral features of several passive fiber optic components are presented. There are spectra of isolators, circulators, spectral filters, and WDM, that are used in quantum key distribution (QKD) systems, and contribute to the protection of these systems against active optical probing attacks. We also provide an estimate of the degree of isolation required to protect the QKD system from Trojan-horse attacks. Based on the isolation requirements and measurement data we analyzed the efficiency of the QKD system protection through the use passive isolating components. As an example, we have shown the achievement of the required isolation level (150 dB) in the considered spectral range in the system presented in the article.

Temperature effect on the light propagation in a tapered optical fiber with a twisted nematic liquid crystal cladding

This paper presents the influence of temperature on optical power spectrum propagated in a tapered optical fiber with twisted nematic liquid crystal cladding (TOF-TNLCC) modulated by an electric field. The measurements were performed for a liquid crystal cell with the twisted orientation of ITO layers, filled with E7 mixture. The induced reorientation of liquid crystal (LC) n-director was measured for visible and near-infrared wavelength range [550-1100 nm] at the electric field range of 0–160 V and temperature range of 20-60 °C. The relation between temperature and the optical power spectrum of the investigated device has been established. Full Text: PDF ReferencesV.J. Tekippe, "Passive fiber optic components made by the fused biconical taper process", Proc. SPIE 1085 (1990). CrossRef T. A. Birks, Y. W. Li, The shape of fiber tapers, Journal of Lightwave Technology 10, 4 (1992). CrossRef J. Korec, K. A. Stasiewicz, O. Strzeżysz, P. Kula, L. R. Jaroszewicz, Electro-Steering Tapered Fiber-Optic Device with Liquid Crystal Cladding, Journal of Sensors 2019: 1-11 (2019) CrossRef Ch. Veilleux, J. Lapierre, J. Bures, Liquid-crystal-clad tapered fibers, Opt. Lett. 11, 733-735 (1986) CrossRef J. F Henninot, D. Louvergneaux, N. Tabiryan, M. Warenghem, Controlled leakage of a tapered optical fiber with liquid crystal cladding, Molecular Crystals and Liquid Crystals, 282, 297-308. (1996). CrossRef Y. Wang, et.al., Tapered optical fiber waveguide coupling to whispering gallery modes of liquid crystal microdroplet for thermal sensing application, Opt. Express 25, 918-926 (2017) CrossRef J. Korec, K. A. Stasiewicz, O. Strzeżysz, P. Kula, L. R. Jaroszewicz, . E. Moś, Tapered fibre liquid crystal optical device, Proc. SPIE 10681 (2018) CrossRef G. Assanto, A. Picardi, R. Barboza, A. Alberucci, Electro-optic steering of Nematicons, Phot. Lett. Poland 4, 1 (2012). CrossRef A.Ghanadzadeh Gilani, M.S. Beevers, The Electro-optical kerr effect in eutectic nematic mixtures of E7 and E8,J ournal of Molecular Liquids, 92, 3 (2001). CrossRef E. C. Mägi, P. Steinvurzel, and B.J. Eggleton, Tapered photonic crystal fibers, Opt. Express 784, 12, 5 (2004). CrossRef Y. Li and J. Lit, Transmission properties of a multimode optical-fiber taper, J. Opt. Soc. Am. A 2, (1985). CrossRef J. Korec, K. A. Stasiewicz, and L. R. Jaroszewicz, Temperature influence on optical power spectrum of the tapered fiber device with a liquid crystal cladding, Proc. SPIE 11045, 110450I (2019) CrossRef L.M. Blinov, Liquid crystals: physical properties and their possibilities in application, Advances in Liquid Crystal Research and Applications, (1981). CrossRef

Automated Multi-Diode Laser System for WDM Couplers Insertion Loss Measurements

Insertion loss is an important parameter used to characterize passive fiber-optic components, such as WDM couplers and variable optical attenuators. This article describes an automated insertion loss measurement system which incorporates 980 nm, 1310 nm, 1529 nm and 1561 nm DFB lasers and two internal fiber optic standards. Insertion loss measurements collected with the system for WDM couplers and internal standards are presented. The system repeatability was validated by measuring the insertion loss for a WDM coupler six times at 980 nm, 1310 nm, 1529 nm and 1561 nm over 3 days period. The standard deviation calculated for the insertion loss measurements is less than 0.11 dB and the %CV is less than 1%.

Optical Single-Sideband Modulators and Their Applications

We review our recent work in the implementation of optical single-sideband (OSSB) modulation and in the application of this modulation format to microwave photonics and optical testing systems. We have developed an enhanced OSSB modulator for wide-band operation, the so-called bidirectional OSSB modulator, and a simplification of this scheme for narrow-band applications. These OSSB modulators are based on the use of a standard single-electrode Mach-Zehnder electro-optic modulator (MZ-EOM) and passive fiber-optic components. In both designs, the OSSB operation is shown to be independent of the MZ-EOM bias. Therefore, the optical modulation depth at the output of the device can be enhanced using minimum transmission biasing to provide suppression of the optical carrier. Finally, we demonstrate the application of OSSB modulators to the improvement of microwave/millimeter-wave subcarrier multiplexing fiber-optic links and to narrow-band fiber radio systems. In addition, we analyzed the feasibility and the limitations of an optical vector network analysis technique based on OSSB modulation that can provide sub-picometer wavelength resolution.

Design and performance of the bidirectional optical single-sideband modulator

We present a detailed study of the design and performance of the bidirectional optical single-sideband modulator (BOSSM). This is a new scheme to achieve optical single-sideband modulation (OSSB) that uses a standard single-electrode Mach-Zehnder modulator (MZ-EOM) and passive fiber-optic components. The design is based on a novel technique to operate electrooptic modulators in which the radio frequency (RF) electrode is bidirectionally driven. The fundamentals of this bidirectional operation are analyzed thoroughly and it is found that it requires the use of a wide-bandwidth MZ-EOM with an electrode design that provides good velocity match between the optical and microwave modes. Deriving the expressions for the optical field and power at the output of the BOSSM, the OSSB operation is shown to be independent of the MZ-EOM bias. Therefore, the optical modulation depth at the output of the device can be enhanced using minimum transmission biasing to provide suppression of the optical carrier. Moreover, it is found that the second-order distortion is unaffected by the MZ-EOM bias; hence the technique can be applied to multi-octave bandwidth systems. Finally, the performance of the BOSSM is evaluated using a prototype based on a commercial 10 Gb/s MZ-EOM. The experimental characterization of the electrooptical parameters of this device reveals that the RF electrode design is not optimized for bidirectional operation. Therefore, the performance of the prototype is limited by the particular MZ-EOM deployed. However, sideband suppression over 10 dB is measured for most frequencies up to millimeter-waves, with peaks in the 20 dB to 30 dB range for narrow bands. This performance has enabled the demonstration of a 22-km fiber link transmitting a 29-GHz subcarrier conveying binary phase-shift keying modulated data at 622 Mb/s. The BOSSM reduces the dispersion-induced power penalty in the link to less than 1.5 dB. Furthermore, the bit error rate of the link is increased by five orders of magnitude using the carrier suppression technique.

Fiber Bragg Grating Writing by Interferometric or Phase-Mask Methods Using High-Power Excimer Lasers

This paper reports the development of high-power excimer lasers with enhanced spatial and temporal coherence. These excimer lasers are applicable to writing fiber Bragg gratings by interferometric or phase-mask techniques. An excimer laser with a novel unstable resonator is analyzed with respect to its suitability to the production of passive fiber-optic components and in terms of production flexibility, efficiency, and reliability. A survey of applicability of this tool to short-and long-period fiber Bragg gratings is presented.

Fiber-optic bus-oriented single-hop interconnections among multi-transceiver stations

The merits of the single-path selective-broadcast interconnection (SBI) implemented in fiber-optic technology are explored. This is a static, passive, fiber-optic interconnection among a set of stations, each equipped with multiple transmitters, and receivers. It uses c/sup 2/ buses, each interconnecting a subset of the stations, and provides a single optical path between any two stations. Thus, it succeeds in decoupling transmission rate from aggregate network throughput. It offers substantial advantages in power budget and the maximum number of stations that can be connected without repeaters and amplifiers. When compared with c buses, each interconnecting all stations, this SBI is attractive in terms of the required passive fiber-optic components such as fiber segments and star couplers. For a fixed power budget, the capacity of this SBI is optimal among bus-oriented single-hop interconnections for both a uniform traffic pattern and worst-case unknown skew. >

Passive fiber-optic components made by the fused biconical taper process

Abstract The rapid development and deployment of optical fiber for a variety of applications has resulted in a similarly rapid development of myriad components to effectively utilize the fiber. Thus, for example, significant work has been done over the past several years in the development of sources and detectors, connectors, and splices. These components share the common trait of being external to the fiber and hence not part of the fiber per se. Another class of components, however, is made from the fiber itself. A number of components, such as polarizers, analyzers, and mode or wavelength filters, require only simple bending of the fiber in a specified manner. On the other hand, such techniques as polishing, etching, and heating can also be used to alter the transmission properties of the fiber. While a number of interesting devices have been made by these procedures, the present paper is limited to devices made by the biconical taper process. If a fiber is heated and stretched, a biconical taper is formed, which can significantly alter the transmission characteristics of the fiber. Interesting wavelength filters and sensors can be made with single tapers or combinations of tapers. Moreover, if two or more tapered fibers are fused, then coupling of light from one fiber to another can be achieved. The tapering and fusing processes can be used to make wavelength-enhanced couplers, which can be used as wavelength-division multiplexers or nearly wavelength-independent couplers or splitters. In this paper, we discuss the components made by the biconical taper process, their fabrication, in both theory and practice, and their performance. Practical implementations of these components are also discussed, including their manufacturability and reliability.