Showing papers on "Single-mode optical fiber published in 1986"
TL;DR: In this article, the theoretical and practical attempts to develop advanced fiber designs have been reviewed, and a detailed review of the existing fiber structures can be found in Section 2.1.
Abstract: Standard first-generation single-mode fibers are optimized for operation at a wavelength of 1.3 μm, where they exhibit zero dispersion. By modifying the fiber design it is possible to shift the zero dispersion wavelength to 1.55 μm, where the lowest losses occur in silica-based fibers. Advanced fiber structures can also be designed such that relatively flat dispersion spectra can be achieved over a wide range of wavelengths. In this paper, the theoretical and practical attempts to develop advanced fiber designs have been reviewed.
183 citations
TL;DR: Efficient and selective coupling between a single-mode fiber and the LP(11) mode of a double-mode Fiber is demonstrated in an evanescent directional coupler that has application as a modal filter for the construction of in-line all-fiber optical components.
Abstract: Efficient and selective coupling between a single-mode fiber and the LP11 mode of a double-mode fiber is demonstrated in an evanescent directional coupler. With greater than 90% coupling to the LP11 mode, suppression of the coupled power to the lower-order LP01 mode was measured to be at least 24 dB. This device has application as a modal filter for the construction of in-line all-fiber optical components.
182 citations
TL;DR: In this article, the results of an investigation into the bend loss as a function of wavelength for single-radius bends in monomode fibers are given, and the effect of the coupling strength between the whispering gallery mode and the fundamental mode on the characteristics of the pure bend loss is discussed.
Abstract: The results of an investigation into the bend loss as a function of wavelength for single-radius bends in monomode fibers are given. The fibers considered have a high numerical aperture and a protective coating which has a refractive index greater than that of the cladding. For these fibers the pure bend loss is shown to be the dominant loss mechanism over the wavelength range 633-1152 nm. In addition, oscillations in the loss are observed as the bend radius is varied at the longer wavelengths. These oscillations are shown to result from the coupling of light under weak coupling conditions from a whispering gallery mode in the cladding formed by the pure bend loss, to the fundamental mode in the core. An expression is derived which relates the bend radius at which the minima in the oscillations occur to the fiber parameters and a qualitative explanation is given for the reduction in the oscillation amplitude as the bend radius and wavelength are decreased. A criterion is identified for assessing the strength of the coupling between the whispering gallery mode and fundamental mode. Using this criterion the attenuation coefficient of the pure bend loss at which a transition from weak to strong coupling occurs is determined and is found to agree with observations. The effect of the coupling strength between the whispering gallery mode and the fundamental mode on the characteristics of the pure bend loss is discussed. Finally, possible applications arising from the results of this work are identified.
164 citations
TL;DR: Tunable CW lasing was achieved for the first time in an Er3+-doped fiber laser, which has an overall tuning range of 25 nm in the region of \lambda = 1.54 /mu m as mentioned in this paper.
Abstract: Tunable laser action has been obtained in Nd3+- and Er3+-doped single-mode fiber lasers. In the case of the Nd3+-doped fiber, an extensive tuning range of 80 nm has been achieved. Tunable CW lasing also has been observed for the first time in an Er3+-doped fiber laser, which has an overall tuning range of 25 nm in the region of \lambda = 1.54 /mu m.
139 citations
TL;DR: The propagation of optical pulses is considered at the zero-dispersion wavelength of nonlinear dispersive fibers of single-mode silica fibers and the evolution of pulse shapes and pulse spectra along the fiber length for a wide range of initial pulse widths is studied.
Abstract: The propagation of optical pulses is considered at the zero-dispersion wavelength of nonlinear dispersive fibers. Even in the absence of group-velocity (first-order) dispersion, higher-order dispersive effects in single-mode silica fibers are found to be strong enough to cause significant broadening and distortion of picosecond optical pulses for fiber lengths of 10\char21{}100 km. Using the parameters appropriate for a 1.55-\ensuremath{\mu}m dispersion-shifted single-mode fiber, we have studied the evolution of pulse shapes and pulse spectra along the fiber length for a wide range of initial pulse widths. For peak powers \ensuremath{\sim}10 mW, the dispersive and nonlinear effects are comparable for pulse widths \ensuremath{\sim}1 ps and their mutual interplay leads to new qualitative features in the pulse shape and spectrum that are largely independent of the input profile. The theoretical results are useful for an understanding of the higher-order dispersion and, at the same time, have implications for high-capacity, long-haul, optical communication systems.
123 citations
103 citations
TL;DR: The effective-index method for determining waveguide dispersion is derived from the scalar wave equation and applied to optical fibers of arbitrary cross-sectional shapes and results from analyzing circular, elliptical, and cusp-shaped fibers are used to illustrate the general features of the method.
Abstract: The effective-index method for determining waveguide dispersion is derived from the scalar wave equation and applied to optical fibers of arbitrary cross-sectional shapes. In the simplest use of the method, the optical fiber is replaced by an equivalent slab waveguide with an index profile derived from the geometrical shape of the fiber. Results from analyzing circular, elliptical, and cusp-shaped fibers are used to illustrate the general features of the method. A procedure is also given for improving the accuracy of the method applied to a class of single-mode fiber.
97 citations
TL;DR: In this article, the temperature dependence of chromatic dispersion in singlemode fibers for a temperature range of -60°-250°C was investigated and the results were independent of fiber coating and structure.
Abstract: This paper describes the temperature dependence of chromatic dispersion in single-mode fibers for a temperature range of -60°- 250°C. Highly accurate dispersion measurements demonstrated a linear relationship (0.025 nm/°C) between the zero dispersion wavelength and temperature for tests conducted below 150°C. Further tests in the high-temperature range showed an increase in this dependence. For both temperature ranges, the results were independent of fiber coating and structure.
95 citations
TL;DR: In this paper, a 1.5?m range multi-electrode distributed feedback laser was tuned electrically, maintaining a stable single-mode oscillation without mode jumping.
Abstract: Broad wavelength tuning under single-mode oscillation is achieved for a 1.5 ?m range multi-electrode distributed feedback laser. The lasing wavelength can be tuned electrically, maintaining a stable single-mode oscillation without mode jumping. The tuning has reached over 20 ? under a noticeable condition of constant power (5mW), with a sufficient side-mode suppression ratio over 30 dB.
91 citations
TL;DR: The drift of an optical fiber gyroscope caused by the earth's magnetic field through the Faraday effect is studied theoretically in a simple model and also in a practical model.
Abstract: The drift of an optical fiber gyroscope caused by the earth's magnetic field through the Faraday effect is studied theoretically in a simple model and also in a practical model. The mechanism of its reduction using polarization-maintaining optical fiber is clarified; it depends on the twist and the birefringence of the fiber. The presence of the twist component whose period is just equal to one turn of the sensing fiber loop causes the drift; ways of suppressing it are described. Influence of the practical parameters, such as imperfection of the polarizer, is also discussed.
90 citations
TL;DR: In this paper, the authors presented transmission characteristics and reliability for pure-silica-core singlemode fiber with matched cladding, and achieved minimum attenuation was 0.154 dB/km at 1.56 µm, which is the lowest attenuation ever reported.
Abstract: Transmission characteristics and reliability for pure-silica-core single-mode fiber with matched cladding are presented. On account of the "pure" silica core, without any additives, the fiber features the low attenuation and improved chemical stability under the existence of hydrogen and γ-ray radiation. High mechanical reliability and good splicing behavior of the fibers were also confirmed. More than 2000 km of pure-silica-core fiber have been fabricated, exhibiting median attenuation of 0.35 dB/km at 1.3 μm and 0.21 dB/ km at 1.55 μm. The achieved minimum attenuation was 0.154 dB/km at 1.55-1.56 \mu m, which is the lowest attenuation ever reported.
TL;DR: In this paper, the performance of a strained-layer superlattice Ge0.6Si0.4 waveguide avalanche photodetectors is evaluated for optical fiber applications at 1.3 μm.
Abstract: Performance of strained‐layer superlattice Ge0.6Si0.4 waveguide avalanche photodetectors is evaluated for optical fiber applications at 1.3 μm. These devices are grown on Si substrates by molecular beam epitaxy. Waveguiding is accomplished by means of a 1.5–1.8‐μm‐thick Si rib waveguide which provides an effective index step of δn=8×10−3. The detector response bandwidth exceeds 8 GHz at a gain of 6. A receiver sensitivity of ηP=−29.4 dBm has been obtained at the data rate of 800 Mb/s with the corresponding error‐free transmission over 45 km of single mode fiber.
TL;DR: In this paper, a beam expander is constructed from a singlemode optical fiber which has been overjacketed in a capillary of lower refractive index and then tapered.
Abstract: A simple practical and controllable beam expander can be constructed from a single-mode optical fibre which has been overjacketed in a capillary of lower refractive index and then tapered. The properties of such an expanded beam in a gap device are also investigated.
TL;DR: In this paper, the dependence of pulsewidth on the electrical drive waveform and the repetition rate is investigated, and limitations on the pulsewidth are discussed, and a composite-cavity structure with an efficient single-mode fiber output port is discussed.
Abstract: Composite-cavity semiconductor lasers using integral single-mode fiber resonators are capable of producing short-duration mode-locked optical pulses at very high repetition rates. This paper summarizes recent experiments using a composite-cavity structure with an efficient single-mode fiber output port. The dependence of pulse-width on the electrical drive waveform and the repetition rate is investigated, and limitations on the pulsewidth are discussed.
TL;DR: In this article, the authors consider the application of single-mode fiber technology to optical networks and the evolution of the technology to all optical networks based on space or wavelength switching, and discuss the progress towards some early experimental networks.
Abstract: For the first time in the history of communications technology, single-mode fiber offers the possibility of truly transparent communications systems. In this paper we consider the application of single-mode fiber technology to optical networks and the evolution of the technology to all optical networks based on space or wavelength switching. Also discussed is the progress towards some early experimental networks.
TL;DR: In this article, a simple architecture for bidirectional optical fiber transmission using an MQW device as both modulator and photodetector was proposed, which achieved transmission of 50 Mbit/s and 600 M bit/s in both directions over one 3.34 km-long single-mode fiber at 860 nm wavelength.
Abstract: We demonstrate a simple architecture for bidirectional optical fibre transmission which uses an MQW device as both modulator and photodetector. We achieved transmission of 50 Mbit/s and 600 Mbit/s in both directions over one 3.34 km-long single-mode fibre at 860 nm wavelength. Coherent Rayleigh interference was found to be a limiting factor in single-source bidirectional systems.
TL;DR: In this paper, the transmission power per channel should be lower than 0 to 5dBm for a subscriber line (5 km) or 10dBm (100 km) for a trunk line (>100 km), employing low-loss dispersion-shifted fiber.
Abstract: The transmission of a multichannel coherent optical system is limited by four-wave mixing. In a 100-channel monomode fibre link, 5 GHz channel separation, ?20 dB crosstalk level, the input power per channel should be lower than 0 to ?5dBm for a subscriber line (5 km), or ?10dBm for a trunk line (>100 km), employing low-loss dispersion-shifted fibre.
Patent•
22 Jan 1986TL;DR: In this article, a single mode optical fiber consisting of a core, a first cladding surrounding the core, and a second cladding region (or index ''ring'') is described.
Abstract: A single mode optical fiber comprises a core (e.g., 10), a first cladding (e.g. 11) surrounding the core, and a second cladding (e.g. 12) surrounding the first cladding. It also comprises a third cladding region (or index ''ring'') (e.g. 13). The core has radius a and refractive index nc, the first, second, and third cladding regions have inner radii, R1i, R2i, and R3i, outer radii R1o, R2o, and R3o, and indices n1, n2, n3, respectively. The fiber has n1 < n3, R1o <= R3i, R3o <= R2i. In preferred embodiments, a = R1i, R1o = R3i, R3o = R2i. Appropriate choice of ring parameters can result in a lowering of the cut-off wavelength of the fiber, or in fiber that is less sensitive to macrobending than similar prior art fiber lacking an index ring, without substantial change in fiber parameters that depend primarily on the waveform in the core. An optical fiber communications system comprising the inventive fiber is also disclosed.
TL;DR: In this article, the spectral characteristics of an external cavity semiconductor laser which uses a phase conjugate mirror for its external reflection were measured using the fiber delay line self-heterodyne technique.
Abstract: We measure the spectral characteristics of an external cavity semiconductor laser which uses a phase conjugate mirror for its external reflection. This device has significant advantages over the conventional external cavity system owing to the self-aligning nature of the phase conjugate mirror. The fiber delay line self-heterodyne technique is used to measure the fundamental linewidth for single mode operation of this device. It shows the linewidth to be at least as narrow as the instrumental resolution of 100 kHz.
09 Jun 1986
TL;DR: In this article, a dispersion compensation delay line is added to a synchronously pumped fiber Raman ring oscillator to generate sub-picosecond pulses, and an interference filter is used as a bandwidth limiting tuning element to provide a good quality short pulse.
Abstract: A dispersion compensation delay line is added to a synchronously pumped fiber Raman ring oscillator to generate subpicosecond pulses. A pair of spaced gratings form the delay line. An interference filter is used as a bandwidth limiting tuning element to provide a good quality short pulse. An integrated design eliminates the discrete optical elements by using only an optical fiber and an optical fiber coupler.
TL;DR: Simple conical microlenses are fabricated on the end of a vapor-axial-deposition single-mode fiber to increase the coupling efficiency between the laser diode and the single- mode fiber.
Abstract: Simple conical microlenses are fabricated on the end of a vapor-axial-deposition single-mode fiber to increase the coupling efficiency between the laser diode and the single-mode fiber. The lowest coupling loss, 3 dB, has been achieved by using a 1.3-μm InGaAsP buried-heterostructure laser diode and a single-mode fiber. Experimental results on coupling efficiency and the loss penalty due to lateral misalignment are also reported. This conical lens is easy to manufacture and reproduce.
TL;DR: In this paper, upper and lower limits for the actual microbending loss of single-mode fibers with arbitrary refractive index profile are given, and it is shown that the minimum splice loss due to a small offset for a given micro bending loss is obtained for a fiber with a Gaussian fundamental mode field.
Abstract: Upper and lower limits for the actual microbending loss of single-mode fibers with arbitrary refractive index profile are given. These limits strongly depend on the shape of the actual fundamental mode field. It is shown that the minimum splice loss due to a small offset for a given microbending loss is obtained for a fiber with a Gaussian fundamental mode field. Fibers with similar splice loss and non-Gaussian fundamental mode fields like multiple-clad single-mode fibers will exhibit significantly larger microbending losses.
TL;DR: Parametric interaction in a single-mode fiber between a carrier and its two sidebands was observed and leads to gain or loss in the two side bands depending on the relative phase between them and is approximately linearly dependent on the carrier power.
Abstract: Parametric interaction in a single-mode fiber between a carrier and its two sidebands was observed. This interaction leads to gain or loss in the two sidebands depending on the relative phase between them and is approximately linearly dependent on the carrier power. A maximum gain of 1.4 was observed at a carrier power of 11 mW.
TL;DR: In this paper, the authors consider the coupling between the guided mode and the cladding modes of a single-mode fiber due to deformations such as microbends of the fiber axis and random core diameter fluctuations.
Abstract: In this paper, we consider the coupling between the guided mode and the cladding modes of a single-mode fiber due to deformations such as microbends of the fiber axis and random core diameter fluctuations. Expressions for the coupling losses are presented for fibers with step-index profiles, and the autocorrelation functions of the microdeformations are assumed Gaussian, characterized by the rms deviation and the correlation length of the random function. In the case of a step-index fiber the results are compared with results found from the theories of Petermann and Marcuse [1], [2] which differ substantially for large correlation lengths. Microbending losses are shown only to differ slightly from the results of Petermann. Both microbending losses and losses due to random core diameter fluctuations differ substantially from Marcuse's results, because of different approximations of the cladding mode fields.
Patent•
28 Jan 1986TL;DR: In this article, a wavelength division multiplexed soliton (WDMS) system is proposed, where the optical solitons of different wavelengths are co-propagating, and collisions between the colliding pulses can be expected to result.
Abstract: The propagation speed of optical solitons in single mode optical fiber depends on the wavelength of the solitons. Thus, if solitons of different wavelengths are co-propagating, "collisions" between pulses can be expected to result. It has been found that collisions between solitons do preserve the soliton character of the colliding pulses, even in the presence of perturbations of the type present in fiber communications systems, e.g., core size variations, distributed or lumped loss, and distributed gain. Thus, a wavelength division multiplexed soliton system is possible, and techniques and formulae for the design of such systems are disclosed. In preferred embodiments, fiber loss is periodically compensated by Raman gain. Typical amplification periods (using currently available silica-based fiber) are 30-50 km, typical pump powers are less than 100 mV, and rate-length products of the order of 3·105 GHz km are possible. Multiplexed soliton systems have several advantages over prior art soliton systems. For instance, they permit attainment of very high transmission rates without the use of very high speed electronics. For instance, an exemplary 3000 km, 24 channel multiplexed soliton system has a total transmission rate of 106 GHz, i.e., 4.5 GHz/channel.
TL;DR: In this article, a fiber-optic current sensor based on the Faraday effect is described which utilizes laser-diode frequency modulation in order to synthesize a heterodyne-type sensor output.
Abstract: A fiber-optic current sensor based on the Faraday effect is described which utilizes laser-diode frequency modulation in order to synthesize a heterodyne-type sensor output. The relative phase of the output carrier is directly modulated by the magnetically induced circular polarization mode-phase delay. Current sensing over three orders of magnitude is demonstrated, and a Verdet constant of 2.57 \times 10^{-6} rad/A (at 0.83μm) is reported for the fiber used.
Patent•
29 Aug 1986TL;DR: In this article, a 15 μm zero-dispersion single mode optical fiber comprising a center core, a side core disposed on an outer side of the center core and having a refractive index lower than that of the centre core, was presented.
Abstract: A 15 μm zero dispersion single mode optical fiber comprising a center core, a side core disposed on an outer side of the center core and having a refractive index lower than that of the center core, and a cladding portion disposed on an outer side of the side core Each of the refractive indices of the center core and the side core has a step-like profile in the direction of the radius of the optical fiber The bending loss is low The mode field diameter can be increased without deteriorating the bending loss, and the splice loss can be reduced The chromatic dispersion varies only to a small extent with respect to changes in the core diameter, so that the zero dispersion wavelength can be well controlled
TL;DR: In this article, a single-mode fiber-optic depolarizer with a Mach-Zehnder interferometer with one arm used as a delay line with respect to the other was proposed.
Abstract: A new type of single mode fiber-optic depolarizer is proposed and demonstrated. The new depolarizer consists of a Mach-Zehnder interferometer with one arm used as a delay line with respect to the other. Light having a 100-MHz spectral width, for example, can be depolarized with high coupling efficiency to single mode fibers by using a polarization-maintaining fiber-delay line of a few meters in length.
TL;DR: An in-line polarizer has been demonstrated that uses the birefringent properties of a nematic liquid crystal placed in the evanescent field of a single-mode fiber to polarize the liquid-crystal molecules.
Abstract: An in-line polarizer has been demonstrated that uses the birefringent properties of a nematic liquid crystal placed in the evanescent field of a single-mode fiber. A polarization-extinction ratio of 45 dB was measured with an insertion loss of 1.1 dB. Amplitude modulation was also demonstrated by using an external electric field to reorient the liquid-crystal molecules.
TL;DR: In this article, the authors present simple and accurate relations for the study of parallel and curved tunable single-mode fiber directional couplers employing step-index or graded-index fibers.
Abstract: We present simple and accurate relations for the study of parallel and curved tunable single-mode fiber directional couplers employing step-index or graded-index fibers. Analytical results for the various coupler parameters such as coupling coefficient, effective interaction length, tunability, and channel wavelength separation in directional coupler wavelength filters are presented. These results must prove very useful for an easy, quick, and accurate prediction or design of tunable single-mode fiber directional couplers.