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Showing papers on "Dispersion-shifted fiber published in 2000"


Journal ArticleDOI
TL;DR: In this article, the authors demonstrate experimentally that air-silica microstructure optical fibers can exhibit anomalous dispersion at visible wavelengths, and exploit this feature to generate an optical continuum 550 THz in width, extending from the violet to the infrared.
Abstract: We demonstrate experimentally for what is to our knowledge the first time that air–silica microstructure optical fibers can exhibit anomalous dispersion at visible wavelengths. We exploit this feature to generate an optical continuum 550 THz in width, extending from the violet to the infrared, by propagating pulses of 100-fs duration and kilowatt peak powers through a microstructure fiber near the zero-dispersion wavelength.

2,372 citations


Journal ArticleDOI
TL;DR: Based on spectral measurements of the polarization mode beating, it is estimated that the strongly anisotropic photonic crystal fiber has a beat length of approximately 0.4 mm at a wavelength of 1540 nm, in good agreement with the results of modeling.
Abstract: We report a strongly anisotropic photonic crystal fiber. Twofold rotational symmetry was introduced into a single-mode fiber structure by creation of a regular array of airholes of two sizes disposed about a pure-silica core. Based on spectral measurements of the polarization mode beating, we estimate that the fiber has a beat length of approximately 0.4 mm at a wavelength of 1540 nm, in good agreement with the results of modeling.

860 citations


Journal ArticleDOI
TL;DR: In this paper, the authors describe the measured group-velocity dispersion characteristics of several air-silica photonic crystal fibers with anomalous group velocity dispersion at visible and near-infrared wavelengths.
Abstract: We describe the measured group-velocity dispersion characteristics of several air-silica photonic crystal fibers with anomalous group-velocity dispersion at visible and near-infrared wavelengths. The values measured over a broad spectral range are compared to those predicted for an isolated strand of silica surrounded by air. We demonstrate a strictly single-mode fiber which has zero dispersion at a wavelength of 700 mm. These fibers are significant for the generation of solitons and supercontinua using ultrashort pulse sources.

683 citations


Journal ArticleDOI
TL;DR: This technique will permit scaling of pulsed fiber lasers and amplifiers to significantly higher pulse energies and peak powers and cw fiber sources to higher average powers while maintaining excellent beam quality.
Abstract: The authors report a new approach to obtain single-transverse-mode operation of a multimode fiber amplifier, in which the gain fiber is coiled to induce significant bend loss for all but the lowest-order mode. They have demonstrated this method by constructing a coiled amplifier using Yb-doped, double-clad fiber with a core diameter of 25 {micro}m and NA of {minus}0.1 (V {approx} 7.4). When operated as an ASE source, the output beam had an M{sup 2} value of 1.09 {+-} 0.09; when seeded at 1,064 nm, the slope efficiency was similar to that of an uncoiled amplifier. This technique does not require exotic fiber designs or increase system complexity and is inexpensive to implement. It will allow scaling of pulsed fiber lasers and amplifiers to significantly higher pulse energies and peak powers and cw fiber sources to higher average powers while maintaining excellent beam quality.

630 citations


Journal ArticleDOI
TL;DR: In this article, the phase-matching conditions of the propagating modes were analyzed and half of the reflection peaks were identified as the reflection to the same mode and the rest as reflection to neighboring modes, and the temperature dependence of each reflection peak is similar to that of a conventional Bragg grating in single-mode fiber.
Abstract: Bragg gratings in optical fibers in multimode propagation are investigated experimentally and theoretically. Bragg gratings formed in optical fibers in multimode propagation show multiple reflection peaks or multiple transmission dips in the reflection or transmission spectra, respectively. For standard graded-index multimode fiber, the number of reflection peaks of a Bragg grating depends on excitation condition of propagating modes. The number of reflection peaks of a Bragg grating at around 1.55 /spl mu/m is 19 for highly multimode excitation and 3-4 for lower order mode excitation. We analyze the phase-matching conditions of the propagating modes and identify half of the reflection peaks as the reflection to the same mode and the rest as the reflection to the neighboring modes. In dispersion-shifted fiber, a Bragg grating at around 0.8 /spl mu/m in three-mode propagation shows three reflection peaks in the reflection spectrum. The temperature dependence of each reflection peak is similar to that of a conventional Bragg grating in single-mode fiber. Polarization dependence measured on a Bragg grating in multimode graded-index fiber is negligible. An advantage of Bragg gratings in multimode fiber (MMF) and the applications are discussed.

267 citations


Journal ArticleDOI
TL;DR: In this article, a return-to-zero data wavelength conversion was demonstrated using cross-phase modulation in an optical fiber with subsequent conversion of phase modulation to amplitude modulation using an optical filter.
Abstract: 40-Gb/s return-to-zero data wavelength conversion is demonstrated using cross-phase modulation in an optical fiber with subsequent conversion of phase modulation to amplitude modulation using an optical filter. The scheme is potentially ultrahigh speed and can be made polarization independent.

159 citations


Journal ArticleDOI
TL;DR: The proposed measurement technique is based on a polarization-sensitive analysis of the backscattered signal and allows one to calculate the correlation length of the random birefringence affecting the fiber.
Abstract: Experimental results of measurement of the beat length and the differential group delay of several types of long single-mode fiber are presented. The proposed measurement technique is based on a polarization-sensitive analysis of the backscattered signal and allows one to calculate the correlation length of the random birefringence affecting the fiber.

152 citations


Journal ArticleDOI
TL;DR: In this paper, a new scheme for all-optical signal reshaping is proposed and demonstrated, where strongly depleted mixing between a CW pump and a noisy non-return-to-zero (NRZ) signal in a common fiber can provide wavelength-converted signals exhibiting excellent intensity-noise cancellation.
Abstract: A new scheme for all-optical signal reshaping is proposed and demonstrated. The strongly depleted mixing between a CW pump and a noisy nonreturn-to-zero (NRZ) signal in a common fiber can provide wavelength-converted signals exhibiting excellent intensity-noise cancellation. Numerical simulations confirm almost complete suppression of intensity fluctuations, simultaneously occurring at several different wavelengths.

138 citations


Journal ArticleDOI
TL;DR: In this article, a fiber grating tap was used as a feedback element to control the in-fiber polarimeter and demonstrated the stable, broadband (>70 nm) operation of the fiber polarimeter.
Abstract: We fabricate highly blazed, polarization-sensitive fiber grating taps and show how these may be used in combination with a UV-induced fiber waveplate to form a compact, in-fiber polarimeter. We show how the polarimeter may be employed as a feedback element to control polarization and use the feedback loop to demonstrate the stable, broadband (>70 nm) operation of the fiber polarimeter.

122 citations


Journal ArticleDOI
TL;DR: In this paper, the temperature dependence of chromatic dispersion is examined for various types of fiber and its coefficient is found to depend strongly on the dispersion slope, and it is shown that dispersion-flattened fiber has a significantly low coefficient of -0.0005ps/nm/km/°C, compared with −0.0038ps/n/km /°C for large-core nonzero dispersion shifted fiber.
Abstract: The temperature dependence of chromatic dispersion is examined for various types of fiber. Its coefficient is found to depend strongly on the dispersion slope. Dispersion-flattened fiber has a significantly low coefficient of -0.0005ps/nm/km/°C, compared with -0.0038ps/nm/km/°C for large-core nonzero dispersion-shifted fiber. Transmission lines with low dispersion slopes consisting of pure silica core fiber and dispersion-compensating fiber also exhibit low coefficients of less than -0.001ps/nm/km/°C because of their compensating effects.

108 citations


Journal ArticleDOI
TL;DR: A long-period grating whose resonance varies in strength but remains fixed in wavelength with either temperature or strain is demonstrated, which requires no spectrometer or other frequency-selective components and can operate in real time.
Abstract: We demonstrate a long-period grating whose resonance varies in strength but remains fixed in wavelength with either temperature or strain. Using this fiber-grating sensor, we resolved a change of 1 muepsilon of strain or 0.04 degrees C in temperature. Such sensors require no spectrometer or other frequency-selective components and can operate in real time.

Journal ArticleDOI
TL;DR: A new approach to measuring displacement and temperature simultaneously by use of a specially designed isosceles triangular cantilevered beam as a strain agent is demonstrated.
Abstract: A new approach to measuring displacement and temperature simultaneously by use of a specially designed isosceles triangular cantilevered beam as a strain agent is demonstrated. A fiber Bragg grating epoxied onto the beam surface is experimentally demonstrated to have a temperature sensitivity of ~0.113 nm/ degrees C below 60 degrees C and a displacement sensitivity of 9.24x10(-2) nm/mm .

Journal ArticleDOI
TL;DR: In this paper, the authors provide accurate estimates of timing and amplitude jitter caused by nonlinear pulse interaction in systems based on highly dispersed optical pulses, both for coherent and non-coherent pulse streams.
Abstract: We provide accurate analytical estimates of timing- and amplitude-jitter caused by nonlinear pulse interaction in systems based on highly dispersed optical pulses, both for coherent and noncoherent pulse streams. We show that the system penalties reduce monotonically with pulsewidth and with increasing fiber dispersion. We demonstrate that proper dispersion pre-compensation can result in a significant reduction of the nonlinear inpairments and provide analytical tools for obtaining the optimal pre-compensation parameters.

Journal ArticleDOI
T. Yamamoto1, E. Yoshida1, K.R. Tamura1, K. Yonenaga1, Masataka Nakazawa1 
TL;DR: In this article, a 640-Gbit/s optical time division multiplexed signal was successfully transmitted over a 92-km zero-dispersion-flattened transmission line.
Abstract: A 640-Gbit/s optical time division multiplexed signal was successfully transmitted over a 92-km zero-dispersion-flattened transmission line. The transmission line consisted of single-mode fiber, dispersion-shifted fiber, and reverse dispersion fiber. By using reverse dispersion fiber instead of dispersion slope compensation fiber, we were able to increase the transmission distance from 63 to 92 km because reverse dispersion fiber has less polarization mode dispersion and a flatter dispersion profile.

Journal ArticleDOI
TL;DR: In this three-cascaded cw Raman laser, based on a single active phosphorus-doped silica fiber, for the first time to the authors' knowledge successive generation of Stokes components of essentially different frequency shifts has been realized.
Abstract: We report a laser-diode-pumped 1407-nm Raman fiber laser with an output power of 1 W. In this three-cascaded cw Raman laser, based on a single active phosphorus-doped silica fiber, for the first time to the authors’ knowledge successive generation of Stokes components of essentially different frequency shifts (1330 and 490 cm-1) has been realized. These Stokes components are associated with both constituents (P2O5 and SiO2) of the fiber core glass.

Journal ArticleDOI
TL;DR: Direct generation of <500-fs pulses at a 1-GHz rate from a self-starting passively mode-locked fiber laser by regeneratively synchronizing the pulses with a phase modulator is reported.
Abstract: We report direct generation of <500‐fs pulses at a 1-GHz rate from a self-starting passively mode-locked fiber laser by regeneratively synchronizing the pulses with a phase modulator. The pulses are amplified and passed through a dispersion-decreasing fiber and a normal-dispersion supercontinuum fiber. The resulting continuum is wider than 350 nm.

Journal ArticleDOI
TL;DR: In this paper, an active Q-switched all-fiber laser based on an acoustically modulated fiber attenuator was implemented for producing 1550.5 nm pulses of 3 /spl mu/J in pulse energy, 150 ns in pulse width, and 5 kHz in pulse repetition frequency.
Abstract: An actively Q-switched all-fiber laser based on an acoustically modulated fiber attenuator was implemented for producing 1550.5 nm pulses of 3 /spl mu/J in pulse energy, 150 ns in pulse width, and 5 kHz in pulse repetition frequency. The fiber attenuator was combined with a fiber Bragg grating, which was used as the end mirror and the wavelength selector of the laser system. The fiber attenuator was implemented with the excitation of transverse vibration by a modulated acoustic wave. The transverse vibration or micro bending led to the coupling of the core mode and cladding modes. Through this mechanism, the feedback level from the fiber grating or the Q factor of the laser can be well controlled. The Q-switched fiber laser based on this scheme can be quite simple.

Journal Article
TL;DR: In this paper, the authors proposed and developed a new technique based on the correlation between the pump and probe lightwaves that excite Stimulated Brillouin Scattering (SBS), which requires interference between the counterpropagating two lightwaves.
Abstract: Brillouin scattering in optical fibers offers a means for distributed strain and/or temperature sensor [1], [2]. Strain or temperature applied to an optical fiber causes a shift in Brillouin gain spectrum. Telecommunicationgrade fibers can be used as sensing medium, and no special process is required to make sensors [1], [2]. Because of these merits, this technique is attractive for application to smart structures [3], [4]. Optical fibers are attached to or embedded in structures for monitoring them. However, the technique developed so far has a spatial resolution limit of the order of several meters. This limit would prohibit application to fine structures such as aircraft’s wing. The resolution limit of the conventional technique is relevant to its pulse-based nature. An optical pulse for generating Brillouin gain has to be longer than the damping time of the acoustic wave. Otherwise, Brillouin gain spectrum (BGS) broadens out making it difficult to determine the spectral center precisely [5]. If we assume the linewidth of the BGS to be 30MHz, the broadening occurs when the pulse width is 3.0 m∗. To circumvent the resolution limit, we have proposed and developed a new technique [6]. It is based on the correlation between the pump and probe lightwaves that excite Stimulated Brillouin Scattering (SBS). SBS requires interference between the counterpropagating two lightwaves. In our technique we control their coherence so as to localize SBS at a specific position in

Journal ArticleDOI
TL;DR: In this paper, the potential of different fiber Bragg grating pairs for simultaneous sensing of strain and temperature is analyzed, and the performance of the proposed technique in simultaneous measurement of temperature and strain is experimentally demonstrated and resolutions of ± 2.5° c/?Hz and ± 26??/?Hz are obtained for a fiber with birefringence of B = 5.5x 10-4.4.
Abstract: The potential of different fiber Bragg grating pairs for simultaneous sensing of strain and temperature is analyzed. We demonstrate that interferometric interrogation of a fiber grating written in bow-tie fiber enables strain and temperature to be simultaneously determined. This is achieved by independent measurement of the shift in the wavelengths of the reflected light from the grating components along the fast and the slow axes of the hi-bi fiber. A detailed theoretical analysis is presented that includes the basic sensing principle, sensor design and demodulation scheme. The performance of the proposed technique in simultaneous measurement of temperature and strain is experimentally demonstrated and resolutions of ± 2.5° c/?Hz and ± 26 ??/?Hz are obtained for a fiber with birefringence of B = 5.5x 10-4.

Journal ArticleDOI
TL;DR: In this article, the authors describe the gain characteristics of thulium-doped fiber amplifiers (TDFA) for wavelength division multiplexing (WDM) signals.
Abstract: We describe the gain characteristics of thulium-doped fiber amplifiers (TDFA) for wavelength division multiplexing (WDM) signals. We optimized the TDF length and the ratio between the forward and backward pump power to realize efficient amplification. The TDFA achieved a gain of over 20 dB and a noise figure of less than 6 dB in the 1353-1483 nm wavelength region at a total pump power of 300 mW for WDM signals input at a total power of -7 dBm.

Journal ArticleDOI
TL;DR: In this article, a graded-index polymer optical fiber containing rhodamine 6G in poly(methyl methacrylate-co-2-hydroxyethyl methACrylate) has been fabricated, which was observed by pumping with a frequency-doubled Q-switched Nd: yttrium-aluminum-garnet laser.
Abstract: A graded-index polymer optical fiber containing rhodamine 6G in poly(methyl methacrylate-co-2-hydroxyethyl methacrylate) has been fabricated. Lasing behavior of the fiber was observed by pumping with a frequency-doubled Q-switched Nd: yttrium–aluminum–garnet laser. A slope efficiency of 43% and a lifetime of 110 000 shots at a repetition rate of 10 Hz have been observed. With a 1.5 mJ pump energy, an output energy of 640 μJ was produced.

Journal ArticleDOI
TL;DR: In this paper, single-channel transmission at 320 Gb/s was demonstrated over a record length of 200 km of nonzero-dispersion fiber using pseudolinear transmission and distributed Raman amplification.
Abstract: Single-channel transmission at 320 Gb/s is demonstrated over record length of 200 km of nonzero-dispersion fiber. Typical terrestrial amplifier spacing of 100 km is achieved by using pseudolinear transmission and distributed Raman amplification. Stable semiconductor electroabsorption modulators are used in the transmitter, demultiplexer, and clock recovery, and uncorrelated multiplexing is employed in the OTDM transmitter.

Proceedings ArticleDOI
30 Nov 2000
TL;DR: In this paper, the authors investigate a new technique to realistically emulate polarization mode dispersion and demonstrate that 15 sections of polarization-maintaining fiber with randomly rotatable connections emulates an almost ideal Maxwellian differential group delay (DGD) distribution.
Abstract: We investigate a new technique to realistically emulate polarization mode dispersion. We demonstrate that 15 sections of polarization-maintaining fiber with randomly rotatable connections emulates an almost ideal Maxwellian differential group delay (DGD) distribution, whereas fixed connections is inadequate.

Journal ArticleDOI
TL;DR: This experiment shows that by utilizing the OWFBG's to select the lasing wavelengths one can achieve fiber lasers with lazing wavelengths and lasing wavelength separations that match the International Telecommunication Union channel-allocation grid well.
Abstract: Eight-wavelength Er-doped fiber lasers with lasing wavelength separations of ∼1.6 and ∼0.8 nm, respectively, have been achieved by use of overlap-written fiber Bragg gratings (OWFBG’s) in the fiber lasers and by cooling of the Er-doped fiber with liquid N2. Our experiment shows that by utilizing the OWFBG’s to select the lasing wavelengths one can achieve fiber lasers with lasing wavelengths and lasing wavelength separations that match the International Telecommunication Union channel-allocation grid well.

Patent
07 Apr 2000
TL;DR: In this article, a cylindrical glass body having a low water content centerline region and method of manufacturing such a glass body for use in the manufacture of optical waveguide fiber is disclosed.
Abstract: A cylindrical glass body having a low water content centerline region and method of manufacturing such a cylindrical glass body for use in the manufacture of optical waveguide fiber is disclosed. The centerline region of the cylindrical glass body has a water content sufficiently low such that an optical waveguide fiber made from the cylindrical glass body of the present invention exhibits an optical attenuation of less than about 0.35 dB/km, and preferably less than about 0.31 dB/km at a measured wavelength of 1380nm. A low water content plug (46, 54) used in the manufacture of such a cylindrical glass body, an optical waveguide fiber having a low water peak, and an optical fiber communication system incorporating such an optical waveguide fiber is also disclosed.

Journal ArticleDOI
TL;DR: In this article, a fiber optic chemical sensor based on gold island surface plasmon excitation is presented, where the sensing part is the end of the fiber onto which a thin layer of gold has been deposited to form a particulate surface.
Abstract: A fiber optic chemical sensor based on gold island surface plasmon excitation is presented. The sensing part of the fiber is the end of the fiber onto which a thin layer of gold has been deposited to form a particulate surface. Annealing the gold reshapes the particles and produces an optical absorbance near 535 nm with the fiber in air. The optical absorption resonance of the gold particles is shifted if the fiber is immersed in a medium other than air. These resonance shifts are examined by transmission spectroscopy through the fiber. Experimental results for the sensitivity and dynamic range in the measurement of liquid solutions are in agreement with a basic theoretical model that characterizes the surface plasmon using nonretarded electrodynamics.

Journal ArticleDOI
TL;DR: In this paper, a nonlinear optical loop mirror (NOLM) is used to convert short pulses at 10 GHz for small group velocity dispersion and walkoff between the control pulses and continuous lightwaves.
Abstract: Wavelength conversion of short pulses at 10 GHz based on a nonlinear optical loop mirror (NOLM) is experimentally and numerically investigated for the case of small group velocity dispersion and walkoff between the control pulses and continuous lightwaves. Experimental and numerical simulation results show that the pulsewidths of the converted signals at different wavelengths are almost the same, and the pulsewidths are compressed when the peak power of the control pulse is smaller than a certain value. An RZ optical source containing eight wavelengths having a high sidemode suppression ratio, equal amplitudes and almost the same pulsewidths is obtained by using wavelength conversion in a NOLM consisting of a common dispersion shifted fiber. 10 Gb/s NRZ wavelength conversion based on the NOLM is demonstrated for the first time and certain conclusions in some of the references are confirmed by our experimental results.

Journal ArticleDOI
TL;DR: A reduced model to describe self-phase modulation-limited fiber transmission in dispersion-managed lightwave systems is presented and by introducing a new figure of merit, the maximum transmission distance versus optical power can be determined without any numerical simulation.
Abstract: A reduced model to describe self-phase modulation (SPM)-limited fiber transmission in dispersion-managed lightwave systems is presented. By introducing a new figure of merit, the maximum transmission distance versus optical power can be determined without any numerical simulation. Together with simplified models for other nonlinear fiber effects, a useful set of design rules for a first-order performance estimation of wavelength-division multiplexed (WDM) systems is established.

Journal ArticleDOI
TL;DR: In this paper, a systematic numerical optimization of pre-and post-compensation normalized sections using standard and dispersion compensating fibers for non-return to zero 10-Gbps/s single channel systems was performed.
Abstract: We perform a systematic numerical optimization of pre- and post-compensation normalized sections using standard and dispersion compensating fibers for non-return to zero 10-Gbits/s single channel systems. By independently varying the power at the different types of fibers inputs and the compensation ratio, we find that the post-compensation performs better than precompensation at the expense of stricter parameter tolerance. Moreover, we show that both pre- and post-compensated systems can be significantly improved by using passive predistortion at the transmitter.

Journal ArticleDOI
TL;DR: In this paper, the authors presented a new technique for fiber Bragg grating (FBG) sensor interrogation and multiplexing, which combines a scanning bandpass filter used to multiplex by wavelength multiple gratings in a single fiber, and an unbalanced Mach-Zehnder fiber interferometer made with a 3/spl times/3 coupler to detect straininduced wavelength shifts.
Abstract: We present a new technique for fiber Bragg grating (FBG) sensor interrogation and multiplexing. The technique combines a scanning bandpass filter used to multiplex by wavelength multiple gratings in a single fiber, and an unbalanced Mach-Zehnder fiber interferometer made with a 3/spl times/3 coupler to detect strain-induced wavelength shifts. A demonstration system interrogates four gratings in a single fiber at a sampling rate up to 20 kHz, with a noise floor measured at less than 10 n/spl epsiv///spl radic/(Hz) above 0.1 Hz.