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Showing papers on "Dispersion-shifted fiber published in 1980"


Journal ArticleDOI
TL;DR: In this paper, the authors reported narrowing and splitting of 7-ps-duration pulses from a mode-locked color-center laser by a 700m-long, singlemode silica-glass fiber, at a wavelength (1.55 \ensuremath{mu}m) of loss and large but negative group-velocity dispersion.
Abstract: This paper reports narrowing and splitting of 7-ps-duration pulses from a mode-locked color-center laser by a 700-m-long, single-mode silica-glass fiber, at a wavelength (1.55 \ensuremath{\mu}m) of loss and large but negative group-velocity dispersion. At certain critical power levels, the observed behavior is characteristic of solitons.

1,844 citations


Journal ArticleDOI
TL;DR: In a bent optical fiber, lateral internal stress induces a birefringence, betab, where r is the fiber radius and R is the bending radius.
Abstract: In a bent optical fiber, lateral internal stress induces a birefringence, betab. At lambda = 0.633 microm in a silica fiber, betab = 7.7 X 10(7) r2 /R2 deg/m, where r is the fiber radius and R is the bending radius.

543 citations


Journal ArticleDOI
TL;DR: The feasibility of maintaining a single-mode optical fiber interferometer in quadrature is demonstrated using a servo driven piezoelectrically stretched coiled fiber with stress voltage coefficient of ~27pi rad/V.
Abstract: The feasibility of maintaining a single-mode optical fiber interferometer in quadrature is demonstrated using a servo driven piezoelectrically stretched coiled fiber. The controller has a range of ~10(-5)-1000 rad with a stress voltage coefficient of ~27pi rad/V.

461 citations


Journal ArticleDOI
A. Hasegawa1, W. Brinkman1
TL;DR: In this article, a tunable coherent infrared (IR) source is presented, which utilizes the sideband produced by modulational instability of an optical signal in a fiber which results from a combination of anomalous dispersion and the nonlinear Kerr effect.
Abstract: A new tunable coherent infrared (IR) source is presented. It utilizes the sideband produced by modulational instability of an optical signal in a fiber which results from a combination of anomalous dispersion and the nonlinear Kerr effect. The generated frequency is in proportion to the square root of the optical pump signal. A coherent IR signal is generated by extracting the sideband.

275 citations


Journal ArticleDOI
Roger H. Stolen1
01 Oct 1980
TL;DR: In this article, the authors presented a procedure for estimating critical power for nonlinear optical processes in single-mode fiber transmission systems, and showed that the effects of self-phase modulation and stimulated Brillouin scattering can appear around 100 mW.
Abstract: Procedures are presented for estimating critical powers for nonlinear optical processes in single-mode fiber transmission systems. Crosstalk due to Raman gain in multiplexed systems can appear at powers of a few mW. The effects of self-phase modulation and stimulated Brillouin scattering can appear around 100 mW while typical stimulated Raman threshold powers are a few watts.

251 citations


Journal ArticleDOI
TL;DR: Both effects of Bend-induced retardation and twist-induced rotation in single-mode optical fibers were found highly reproducible and to have small temperature dependence.
Abstract: Bend-induced retardation and twist-induced rotation in single-mode optical fibers are important variables in the design of optical fiber current measurement systems. Bend-induced retardation varies with the square of the curvature and is believed caused by a waveguide geometry effect. Twist-induced rotation varies with the angle through which the fiber is twisted and is produced by torsional strain in the fiber. Both effects were found highly reproducible and to have small temperature dependence. Neither effect should significantly limit the performance of optical measurement systems using single-mode fibers.

192 citations


Journal ArticleDOI
TL;DR: A simple optical-pulse-equalization technique for minimizing pulse dispersion in a single-mode fiber transmission system utilizing the positive- and the negative-dispersion characteristics of single- mode fibers on both sides of a zero-chromatic-disPersion wavelength is described.
Abstract: We describe a simple optical-pulse-equalization technique for minimizing pulse dispersion in a single-mode fiber transmission system utilizing the positive- and the negative-dispersion characteristics of single-mode fibers on both sides of a zero-chromatic-dispersion wavelength.

186 citations


Journal ArticleDOI
TL;DR: Periodic phase changes in the 10(-6) -rad region have been induced and detected in a single-mode all-fiber Mach- Zehnder interferometer by stretching the fiber with a piezoelectric cylinder driven at frequencies between 40 and 10(4) Hz.
Abstract: Periodic phase changes in the 10(-6) -rad region have been induced and detected in a single-mode all-fiber Mach- Zehnder interferometer by stretching the fiber with a piezoelectric cylinder driven at frequencies between 40 and 10(4) Hz.

182 citations


PatentDOI
15 Aug 1980
TL;DR: In this article, the cross-talk between adjacent cores in the optical waveguide can be optimized to respond to a change in hydrostatic pressure (20) or in unidirectional strain along the length of the fiber.
Abstract: An optical fiber (10) having at least two cores (12 & 14) positioned in a common cladding (16) can be fabricated to be responsive to strain or hydrostatic pressure (20) but not to temperature through the selection of materials, spacing and shape of the cores and cladding in the fiber. Accordingly, the cross-talk between adjacent cores (12 & 14) in the optical wave-guide (10) can be optimized to respond to a change in hydrostatic pressure (20) or in unidirectional strain along the length of the fiber. The strain or pressure change, can be determined by measuring (22 & 24) the relative intensity of light emerging from the different cores of the fiber. A larger unambiguous range for strain or hydrostatic pressure (20) changes can be provided by a multi-core optical fiber embodiment.

157 citations


Journal ArticleDOI
Akira Hasegawa1
TL;DR: The nonlinear change of the dielectric constant (Kerr effect) in a glass fiber can be utilized to self-confine optical pulses in a multimode fiber at wavelengths longer than 1.3 microm.
Abstract: The nonlinear change of the dielectric constant (Kerr effect) in a glass fiber can be utilized to self-confine optical pulses in a multimode fiber at wavelengths longer than 1.3 μm. The range of the deviation in the group velocity Δνg of the different modes to be confined is given by Δνg2/νg2 ≤ 2(∂νg/∂f × f/νg)n2/n0|E|2, where f and νg are the frequency and the group velocity, respectively, of the mode; n0 and n2 (= 3 × 10−22 m2/V2) are the linear and nonlinear indices of refraction; and E is the peak electric field averaged over the cross sections of the fiber.

122 citations


Journal ArticleDOI
TL;DR: Polarization beat lengths down to 2.5 cm have been realized this way, providing excellent polarization holding.
Abstract: Coiling a single-mode fiber of radius r under tension onto a cylinder of radius R produces a linear birefringence of βtc ≃ 28 × 107∊2r/R deg/m in the fiber at λ = 0.63 μm, where ∊z is the relative fiber elongation. Polarization beat lengths down to 2.5 cm have been realized this way, providing excellent polarization holding.


Patent
28 Feb 1980
TL;DR: A fiber optic device consisting of an optical fiber/interference filter combination finds useful application in optical communication systems for wavelength selection or bandwidth selection from a multiwavelength light source or emitter as discussed by the authors.
Abstract: A fiber optic device basically comprising an optical fiber/interference filter combination finds useful application in optical communication systems for wavelength selection or bandwidth selection from a multiwavelength light source or emitter. If the emitter is a semiconductor laser, the device may be also employed to provide single longitudinal mode control at the selected wavelength or bandpass.

Patent
Roman Maciejko1
10 Nov 1980
TL;DR: A fiber optic system element for reducing speckle and modal noise resulting from coupling a laser diode to an optical fiber has the form of a short length of fiber through which extend filaments of different refractive indices.
Abstract: A fiber optic system element for reducing speckle and modal noise resulting from coupling a laser diode to an optical fiber has the form of a short length of fiber through which extend filaments of different refractive indices. Such fiber is fabricated by fusing together a plurality of fibers of different refractive index profiles and drawing the resulting preform into a single fiber.

Journal ArticleDOI
TL;DR: Elastic and elastooptic coefficients used to predict acoustic response sensitivity for two single-mode optical fibers have been determined from Brillouin scattering measurements, finding that this assumption introduces no more than a 5% error in the pressure sensitivity for a low numerical aperture (N.A.) fiber.
Abstract: Elastic and elastooptic coefficients used to predict acoustic response sensitivity for two single-mode optical fibers have been determined from Brillouin scattering measurements. These measurements were made on two ITT single-mode fiber preforms currently of interest in the fabrication of fiber-optic acoustic sensors. Previous predictions of acoustic sensitivity assumed the optical fiber waveguides as homogeneous fused silica cylinders. It was found that this assumption introduces no more than a 5% error in the pressure sensitivity for a low numerical aperture (N.A.) fiber and a 30% error for a high N.A. fiber.

Patent
20 Mar 1980
TL;DR: In this article, a fiber optic energy sensor and optical demodulation system is described where the signal energy to be sensed or detected causes an etched single mode fiber to be stretched or compressed which causes the optical path length for electromagnetic radiation traveling in the core of the optic fiber to change.
Abstract: A fiber optic energy sensor and optical demodulation system is disclosed wherein the signal energy to be sensed or detected causes an etched single mode fiber to be stretched or compressed which causes the optical path length for electromagnetic radiation traveling in the core of the optic fiber to change. The change in optic path length modulates the electromagnetic radiation traveling in the fiber. There is also disclosed novel methods of manufacturing the novel type of fiber optic energy sensor and optical demodulation system.

Journal ArticleDOI
TL;DR: When light is coupled into or out of an optical fiber through a normally cut end face, reflection may set up disturbing standing waves but can be avoided by a slight tilt of the end face of the fiber and a corresponding inclination of the Fiber axis.
Abstract: When light is coupled into or out of an optical fiber through a normally cut end face, reflection may set up disturbing standing waves. They can be avoided by a slight tilt (≃ 12°) of the end face of the fiber and a corresponding inclination of the fiber axis. Residual reflections of −58 to −68 dB are obtained.

Journal ArticleDOI
TL;DR: In this article, the wavelength dispersion characteristics of single-mode silica fibers in a very low-loss region, including zero dispersion wavelengths, are studied in detail using a "difference method."
Abstract: Wavelength dispersion characteristics of single-mode silica fibers in a very low-loss region, including zero dispersion wavelengths, are studied in detail using a "difference method." Wavelength dispersion of single-mode fibers is compared for fibers with same material dispersion but with different waveguide structure. Material dispersion is evaluated by extracting waveguide dispersion from experimental results. Effects of waveguide dispersion on the zero dispersion wavelength of the single-mode fiber in a longer wavelength region are clearly analyzed. Single-mode fiber design consideration is given from the wavelength dispersion point of view.

Journal ArticleDOI
TL;DR: In this article, a modified floating zone technique is proposed to draw fiber single crystal for infrared optical waveguides using this technique, KRS-5 fiber single crystals with 06~1 mm in diameter were prepared at the high growth rate of 05~3 cm/min up to 2m in length.
Abstract: Modified floating zone technique is proposed to draw fiber single crystal for infrared optical waveguides Using this technique, KRS-5 fiber single crystals with 06~1 mm in diameter were prepared at the high growth rate of 05~3 cm/min up to 2m in length The fiber crystals have a circular cross-section and high plasticity to be bent freely at room temperature

Journal ArticleDOI
TL;DR: In this paper, the radiation-induced optical absorption of high purity silica and doped silica glass in the visible and near infrared has been studied using the long path length afforded by low loss optical fiber waveguides.
Abstract: The radiation-induced optical absorption of high purity silica and doped silica glass in the visible and near infrared has been studied using the long path length afforded by low loss optical fiber waveguides This technique has permitted the investigation of previously unobserved bands of low absorption coefficient in this spectral region Absorption measurements were made during steady state irradiation, after pulsed irradiation and at long times following irradiation over the 04–17 μ region Photobleaching of induced bands centered near 700 nm in high purity synthetic silica core fibers has been studied, and the effects of dopants such as Ge, P, B, F, and Cs on the absorption spectra have been investigated

Journal ArticleDOI
TL;DR: In this article, a double-core single-mode optical fiber intended for use as a directional coupler was used for tuning couplers and the coupling ratio was found to be 13% due to a change in the phase velocity difference caused by a 4 to 5% difference between core diameters.
Abstract: This work describes the preparation and testing of a double-core single-mode optical fiber intended for use as a directional coupler A short survey of optical directional coupler theory is followed by a description of the preparation of the double-core preform The drawn fibers have a core diameter of 5μm with a spacing between core centers of 13μm Sections of the double-core fiber were tested at λ=633 nm and 876 nm The coupling factor measured for straight fiber sections of different length was found to be considerably lower than that calculated assuming equal phase velocities for both waveguides This was concluded to be due to a difference between phase velocities caused mainly by a 4 to 5% difference between core diameters At 876 nm a maximum coupling ratio of 13% was observed Bending the fiber section was found to influence the coupling factor due to a change in the phase velocity difference This effect can be utilized for tuning couplers A double-core fiber section may be applied as a sensor for measuring the bending angle

Journal ArticleDOI
TL;DR: Wavelength-divisionmultiplexing (WDM) transmission, by which different wavelength signals are transmitted via a single optical fiber, is considered to be a promising technology for future systems, especially for subscriber loops and large-capacity transmission systems.
Abstract: Optical fiber transmission technology has developed rap­ idly due to improvements in fabrication of optical fibers, light sources, and other optical devices. Wavelength-divisionmultiplexing (WDM) transmission, by which different wavelength signals are transmitted via a single optical fiber, is considered to be a promising technology for future systems, especially for subscriber loops and large-capacity transmission systems. In a WDM system, a multi/demultiplexer is an essential part of the optical sender and receiver. Many types of multi/demultiplexer having good performances have al­ ready been developed. A demultiplexer using a plane


Journal ArticleDOI
01 Oct 1980
TL;DR: In this paper, the authors describe state-of-the-art measurement techniques for the characterization of fiber loss and dispersion in the 0.8 to 1.7 µm wavelength region.
Abstract: This paper describes state-of-the-art measurement techniques for the characterization of fiber loss and dispersion. Special emphasis is placed on the achievement of high measurement accuracy, and on novel techniques to determine the loss and dispersion of single-mode and graded-index fibers in the 0.8 to 1.7-µm wavelength region where fiber loss and material dispersion are both small.

Proceedings ArticleDOI
01 Jan 1980
TL;DR: In this paper, an optical fiber interferometer was developed for the detection of ultrasonic waves in solids, where light emerging from the output ends of the reference fiber and a signal fiber which was embedded in a 2.54 cm disc of plastic resin 1.1 cm thick was superimposed to form a straight line interference pattern.
Abstract: An optical fiber interferometer has been developed for the detection of ultrasonic waves in solids. The optical paths in both the signal and reference arms of the Mach-Zehnder interferometer are through the cores of similar lengths of single mode fiber mode stripped at both input and output. Light emerging from the output ends of the reference fiber and a signal fiber which was embedded in a 2.54-cm disc of plastic resin 1.1-cm thick was superimposed to form a straight line interference pattern. Instantaneous translation of the pattern is proportional to the localized strain produced by ultrasonic bulk waves generated in the disc and integrated along the fiber path. By spatially filtering the moving fringe pattern and synchronously demodulating the filtered optical intensity distribution, a signal proportional to the integrated strain is obtained. Direct calibration at dc indicates a minimum theoretical detectable strain of less than

Journal ArticleDOI
S. Masuda1
TL;DR: A novel compact optical variable-attenuator with a wide dynamic range for use in single-mode fiber transmission systems has been developed and Reproducibility of the attenuation is within 0.5 dB.
Abstract: A novel compact optical variable-attenuator with a wide dynamic range for use in single-mode fiber transmission systems has been developed. Attenuation rate can be continuously adjusted by changing the distance between the end faces of the two fibers in the V-channel on a concave surface. The calculated insertion loss is <0.5 dB; the dynamic range of 30 dB is attained by <2.5 mm end separation. The calculated losses were verified experimentally. Reproducibility of the attenuation is within 0.5 dB.

Journal ArticleDOI
TL;DR: It is shown that, in the special case of a step-index fiber, the PDF is a gamma distribution of argument M′, where M′ is the number of degrees of freedom in the speckle pattern and measurements of the PDF show good agreement with calculated gamma distributions.
Abstract: With a sufficiently narrow source spectrum, and either fiber movement or source frequency shift, a changing speckle pattern exists at a multimode-fiber output plane that results in modal noise. Daino and co-workers [Electron. Lett. 15, 755 (1979)] have obtained the noise probability density function (PDF) for a fiber of arbitrary refractive-index profile in the limiting cases in which the number of speckles seen by the detector is either very small or very large. We show that, in the special case of a step-index fiber, the PDF is a gamma distribution of argument M′, where M′ is the number of degrees of freedom in the speckle pattern. We report measurements of the PDF that show good agreement with calculated gamma distributions.

Journal ArticleDOI
TL;DR: It is shown that thermally induced phase effects can be reduced by jacketing fibers with elastomers having certain thermal properties, and predicted for an infinitely long uniform-index fiber.
Abstract: Induced optical phase effects attributed to time varying temperatures at the fiber surface in single-mode fiber optic interferometric sensors are calculated. A Green's function approach is used for predicting temperature distributions within fibers for general time-dependent external temperatures. Analytic expressions for temperature distributions within fibers exposed to external linear, step, and sinusoidal temperature variations are derived using standard differential equation methods, assuming heat conduction to be the only heat transfer mechanism. With these expressions, thermally induced optical phase effects are predicted for an infinitely long uniform-index fiber. Plots are given that show the significance of fiber diameter and thermal properties on the time-dependent behavior of thermally induced phase effects for specific external temperature variations. It is shown that thermally induced phase effects can be reduced by jacketing fibers with elastomers having certain thermal properties.

Journal ArticleDOI
TL;DR: A simple spatial method using a coherent light source and an interferometer for measuring the group delay time difference between the LP(01) and LP(11) modes in a dual-mode optical fiber is proposed.
Abstract: A simple spatial method using a coherent light source and an interferometer is proposed for measuring the group delay time difference between the LP(01) and LP(11) modes in a dual-mode optical fiber. Experimental results obtained by this method are in good agreement with those obtained by the swept-frequency and pulse methods. Moreover, a group delay time difference of 4 psec is measured. Results suggest that this spatial. method can be applied to a short fiber less than 1 m in length and/or small time differences around 1 psec by using a laser diode with a short coherence length.

Journal ArticleDOI
TL;DR: In this article, a melt grown cesium iodide crystalline fiber whose transparency extends from the ultraviolet to infrared region was reported, and transmission losses of the fiber inserted in a teflon jacket were measured at the wavelengths of 0.63 and 10.6 µm.
Abstract: We report a melt grown cesium iodide crystalline fiber whose transparency extends from the ultraviolet to infrared region. Transmission losses of the fiber inserted in a teflon jacket are measured at the wavelengths of 0.63 and 10.6 µm, and in the spectral range from 0.8 to 1.6 µm, respectively. Overall optical and mechanical properties of the fiber show its availability.