Single-mode Optical Fiber Cable Research Articles

Experimental Measurements of Attenuation and Recovery within Single Mode Optical Fiber Cables under the Effects of Gamma Radiation

Efficient transmission of data within optical fiber cables within radiation environments is a challenge. It leads to severe attenuations in the optical fiber cables. This issue is addressed in this manuscript. Experimental measurements are conducted in order to overcome the radiation influence on single mode optical fiber cables. Two experiments are implemented. The first one depends on 5 m single mode patch cords fiber cable. This cable is subjected to gamma radiation

Distributed Fiber Optic Strain Sensing for Geomechanical Monitoring: Insights from Field Measurements of Ground Surface Deformation

In recent years, distributed fiber optic strain sensing (DFOSS) technology has demonstrated a solution for continuous deformation monitoring from subsurface to surface along the wellbore. In this study, we installed a single-mode optical fiber cable in a shallow trench to establish an effective technique for ground surface deformation mapping. We conducted three experimental field tests (iron plate load, water tank filling up load, and airbag inflation) in order to confirm the strain sensitivity of DFOSS for static loads, dynamic overload, excavation, subsidence, and uplift. This paper also presents two installation methods to couple the fiber cable with the ground under various environmental conditions; here, the fiber cable was installed in a shallow trench with one part buried in the soil and another part covered with cement. Our results suggest that covering the cable with cement is a practical approach for installing a fiber cable for ground surface deformation monitoring. By combining this approach with wellbore DFOSS, accurate surface–subsurface deformation measurements can be obtained for three-dimensional geomechanical monitoring of CO2 storage and oil and gas fields in the future.

Broadband 60 GHz Sounder for Propagation Channel Measurements Over Short/Medium Distances

This paper presents a millimeter-wave propagation-channel sounder that uses an optical-fiber cable to achieve phase coherence between transmitting and receiving antennas using two modulated light waves in the vicinity of 1550 nm. In the described sounder, the optical-fiber cable approach permits a separation of up to almost 1000 m between the transmitter and receiver because of the low level of attenuation per unit length in a single-mode optical-fiber cable. The measurement system can sweep from 500 MHz below 60.1 GHz (59.6 GHz) to 500 MHz above 60.1 GHz (60.6 GHz) and proceed to 10 001 in-phase and in-quadrature propagation channel measurements in ${\sim}{\rm 5}~{\rm sec.}$ Measurements of the frequency response of nonline-of-sight and line-of-sight indoor/outdoor propagation channels over medium $({>}{\rm 100}~{\rm m})$ and short ranges can be performed for two or more different lateral receiving antenna positions for antenna diversity studies.

Feedforward Linearization Technique for Reducing Nonlinearity in Semiconductor Optical Amplifier

This paper investigates the first demonstration of linearization of semiconductor optical amplifier (SOA) using feedforward linearization. To improve the linearity and suppressing the four-wave mixing (FWM) of SOA, the amplifier uses the feedforward technique. This technique should be applicable to any microwave or even millimeter frequency band and any externally modulated laser. Link performance was evaluated for single-tone noise reduction and two-tone FWM suppression. Theoretical simulation results are presented, showing a distortion cancellation produce by SOA of better than 20 dB over 1550-nm single-mode optical-fiber cable. This technique has been used to successfully transmit data, both directly and indirectly modulated, using a laser diode at a 2.5-Gb/s light-wave transmission system in simulation.

PROPAGATION CHARACTERISTICS OF IRRADIATED BINARY GLASS OPTICAL FIBERS IN THERMAL FIELDS

In the present paper, the penalties of performance of single mode optical fiber cables employed in thermo-irradiated fields in nuclear projects environments and space communication systems have been analyzed deeply and parametrically. Irradiation effects as well as the thermal effects are modeled based on experimental measurements, the investigated over the practical ranges of interest. Spectral losses as well as total chromatic dispersion are considered for thermal-irradiation dependences. Four dependent effects {spectral losses, pulse spreading, fiber bandwidth, and transmitted bit rate} are then investigated. Severe reduction effects of both thermal field and irradiation field are assured and concluded. Comparison between the present case and the irradiation-free case at room temperature is made. Three cases of special impact at three special windows are studied namely: dispersion-free, losses-free (minimum), and OH-losses-free. It is found that the maximum available bit rate is 5.89 Tbit/sec at optical wavelength l=1.59 mm at OH-free, no marginal losses and dose-free case.

First measurement of strain distribution along field-installed optical fibers using Brillouin spectroscopy

Strain distributions along optical fibers in a 1.3-km-long cable before and after installation are measured using Brillouin optical-fiber time domain analysis. The residual strains in the installed optical fibers were found to vary from zero to 0.07%, depending on the conduit configuration and installation procedure. Strain distribution measurements were carried out on a 24-fiber slotted-core type single-mode optical fiber cable for 1.55- mu m-wavelength transmission, whose length, outer diameter, and weight were 1.3 km, 14 mm, and 0.18 kg/m, respectively. No clear relation between strain distributions and the fiber configuration in the test cable are found.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Polarization fluctuation measurements on installed single-mode optical fiber cables

Measurements are reported of the polarization fluctuation observed at 1550 nm on samples of cable that Telecom Australia has installed in its interexchange network. The rate of polarization fluctuations is found to be slow, on the order of hours. The fluctuation in the polarization angle is typically in the range of 2-10 degrees each day, with some changes up to about 25 degrees . The results indicate there are no significant limitations on implementing polarization control in a coherent system receiver. >

Optical fiber cables for subscriber loops

The use of single-mode optical fiber cables in the local network is discussed. For various network structures, cable constructions with loose buffered fibers, ribbon, and V-groove elements are discussed. For star networks, cables with up to 2000 fibers are described. Cables for bus/star networks are also discussed. Splicing techniques and enclosures are considered. It is concluded that only mass splicing technologies with ribbons will lead to the required results.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Thermal characteristics of optical pulse transit time delay and fiber strain in a single-mode optical fiber cable

Thermal characteristics of optical pulse transit time delay and fiber strain in a single-mode optical fiber cable are investigated theoretically and experimentally. Measurements of the transit time delay shift are made by a spatial interference technique using a 1.5-in long fiber, six-fiber unit, and cable. Experimental results for a jacketed fiber whose fiber axis is well centered in nylon coating are in good agreement with those predicted from the theory. A jacketed fiber whose fiber axis is positioned eccentrically from the jacket center exhibits a small change in fiber strain at low temperature due to fiber buckling compared with that for the well-centered jacketed fiber. The loss increase for the off-centered jacketed fiber is explained by the buckling model. Furthermore, thermal characteristics of the unit-type cable examined here are found to coincide with those for the constituent six-fiber unit.

Temperature stability of transit time delay for a single-mode fibre in a loose tube cable

The effect of temperature on the transit-time delay of a loose-tube-type single-mode optical-fiber cable is investigated experimentally. A 1058-m length of cable was placed loosely coiled in an oven and used to connect a 820-nm single-mode laser diode to a high-speed avalanche-photodiode detector feeding a vector voltmeter; the signal was provided by a high-stability frequency-synthesized generator. Measurements were made every 2 C from -50 to 60 C and compared to those obtained with a 200-m lacquered bare fiber. The phase change of both fibers varied with temperature at a positive slope of 6-7 ppm/C. This value is significantly better than those reported for other cable types, suggesting the application of loose-fiber cables to long-haul gigabit digital transmissions or precision time-base distribution for VLBI.

Single-mode optical fiber cable

A single-mode optical fiber cable was manufactured; loss increase characteristics due to cabling were evaluated. The existence of wide V-value regions without cabling loss increases is shown by a suitable selection of fiber parameters and optical wavelengths. A selection method for fiber parameters, which minimizes cabling and splicing loss increases, is discussed. Selected values are Delta = 0.2% and V = 2.2, based on experimental results.