Showing papers in "Optics Letters in 1988"
TL;DR: A nonlinear device based on the nonlinear propagation in a waveguide loop formed by connecting the output ports of a conventional coupler is proposed and has the ability to operate on entire pulses when soliton effects are included.
Abstract: A nonlinear device for ultrafast processing is proposed. This device is based on the nonlinear propagation in a waveguide loop formed by connecting the output ports of a conventional coupler. The device is shown to have potentially useful characteristics for unequal coupling ratios and has the ability to operate on entire pulses when soliton effects are included.
1,006 citations
TL;DR: It is shown that a nonlinear array of coupled waveguides can exhibit discrete self-focusing that in the continuum approximation obeys the so-called nonlinear Schrödinger equation.
Abstract: We show that a nonlinear array of coupled waveguides can exhibit discrete self-focusing that in the continuum approximation obeys the so-called nonlinear Schrodinger equation. This process has much in common with the biophysical model of Davydov.
998 citations
TL;DR: A simple iterative technique has been developed for blind deconvolution of two convolved functions and a number of results obtained from a computational implementation are presented.
Abstract: A simple iterative technique has been developed for blind deconvolution of two convolved functions. The method is described, and a number of results obtained from a computational implementation are presented. Some further possible applications are indicated.
756 citations
TL;DR: A first series of in vivo measurements acoustically determined eye length, with a multimode semiconductor laser, within a precision of 0.03 mm.
Abstract: With a multimode semiconductor laser we have been able to measure the optical length of the eye within a precision of 0.03 mm. A first series of inυiυo measurements of several human beings shows good correlation with the acoustically determined eye length.
654 citations
TL;DR: By recirculating 55-psec soliton pulses many times around a closed 42-km loop with loss exactly compensated by Raman gain, pulse transmission is successfully demonstrated over distances in excess of 4000 km.
Abstract: By recirculating 55-psec soliton pulses (λs ~ 1600 nm) many times around a closed 42-km loop with loss exactly compensated by Raman gain (λp ~ 1497 nm), we have successfully demonstrated pulse transmission, without electronic regeneration, over distances in excess of 4000 km.
296 citations
TL;DR: All-optical switching of solitons between the two linear modes of a nonlinear coherent coupler made from a dual-core fiber operating in the anomalous dispersion regime is predicted.
Abstract: We predict all-optical switching of solitons between the two linear modes of a nonlinear coherent coupler made from a dual-core fiber operating in the anomalous dispersion regime.
287 citations
TL;DR: It is shown that a novel class of optical solitons is possible in nonlinear dispersive media with birefringence.
Abstract: It is shown that a novel class of optical solitons is possible in nonlinear dispersive media with birefringence.
269 citations
TL;DR: Measurements of pulse reshaping by the nonlinear coupler provide compelling evidence of the device's ability to response on a femotosecond time scale.
Abstract: We report all-optical switching of 100-fsec pulses in a fused-quartz dual-core-fiber directional coupler. The length of the device is 0.5 cm, and the switching power is 32 kW. Pulses are routed to either of two separate fiber guides, depending on the input power. Measurements of pulse reshaping by the nonlinear coupler provide compelling evidence of the device's ability to response on a femotosecond time scale.
269 citations
TL;DR: It is proposed that frequency-domain encoding and decoding of coherent ultrashort pulses could form the basis for a rapidly reconfigurable, code-division multiple-access optical telecommunications network.
Abstract: We demonstrate the spreading of femtosecond optical pulses into picosecond-duration pseudonoise bursts. Spreading is accomplished by encoding pseudorandom binary phase codes onto the optical frequency spectrum. Subsequent decoding of the spectral phases restores the original pulse. We propose that frequency-domain encoding and decoding of coherent ultrashort pulses could form the basis for a rapidly reconfigurable, code-division multiple-access optical telecommunications network.
254 citations
TL;DR: A comparison of beam divergence and power-transport efficiency is made between Gaussian and Bessel beams when both beams have the same initial total power and the sameInitial full width at half-maximum.
Abstract: A comparison of beam divergence and power-transport efficiency is made between Gaussian and Bessel beams when both beams have the same initial total power and the same initial full width at half-maximum.
251 citations
TL;DR: It is shown that twisted nematic liquid-crystal spatial light modulators behave as phase-only modulators when operated below the conventional optical threshold and behave as spatial amplitude modulator when used between crossed polarizers above the optical threshold.
Abstract: It is shown that twisted nematic liquid-crystal spatial light modulators behave as phase-only modulators when operated below the conventional optical threshold. Thus such devices, when operated in a reflection mode, behave as spatial amplitude modulators when used between crossed polarizers above the optical threshold; they behave as phase modulators when used between parallel polarizers and operated below that threshold.
TL;DR: In this paper, a superheterodyne detection (SHD) technique is presented, which permits measurement of the phase difference of two optical frequencies that cannot be resolved by direct optoelectronic HD detection.
Abstract: In two-wavelength interferometry, synthetic wavelengths are generated in order to reduce the sensitivity or to extend the range of unambiguity for interferometric measurements Here a novel optoelectronic technique, called superheterodyne detection, is presented, which permits measurement of the phase difference of two optical frequencies that cannot be resolved by direct optoelectronic heterodyne detection This technique offers the possibility for operation of two-wavelength interferometry in real time with arbitrary synthetic wavelengths from micrometers to meters in length Preliminary experimental results are reported An optical arrangement for absolute range-finding applications using tunable-laser sources (eg, semiconductor lasers) is proposed
TL;DR: Polarization dispersion in single-mode fiber with random polarization mode coupling is given a statistical treatment based on the recently proposed principal-states model and the variance is shown to have a linear dependence on length while the probability density function for the delay time approaches a Gaussian shape.
Abstract: Polarization dispersion in single-mode fiber with random polarization mode coupling is given a statistical treatment based on the recently proposed principal-states model. An expression for the ensemble variance of the differential delay time between the principal states of polarization is derived by using coupled-mode theory under the assumption of weak coupling. For long fiber lengths, the variance is shown to have a linear dependence on length while the probability density function for the delay time approaches a Gaussian shape.
TL;DR: Channel waveguides and Mach-Zehnder interferometers fabricated in LiNbO(3) by annealed proton exchange showed no variation in insertion loss or switching voltage was observed over 8 months for devices stored at room temperature.
Abstract: Channel waveguides and Mach–Zehnder interferometers were fabricated in LiNbO3 by annealed proton exchange. The waveguides had a loss of 0.15 dB/cm and a fiber-to-fiber insertion loss of 1.2 dB at 0.8 μm. The measured r33 electro-optic coefficient of the interferometers was 30 × 10−12 m/V ±5%, which agrees well with theory, indicating that there is no degradation in the r33 coefficient. No variation in insertion loss or switching voltage was observed over 8 months for devices stored at room temperature.
TL;DR: The analysis shows that the fiber fuse is a new kind of solitary thermal shock wave in whose leading edge the temperature gradients can reach several thousand kelvins per micrometer.
Abstract: Fresh experimental and theoretical results on thermally induced catastrophic breakdown (the fiber fuse) in optical fibers are presented, including the observation that the damage is not always irreversible and an analysis of the complex unsteady absorption–heat-conduction process that controls the effect. Good agreement with experiment is obtained with just two independent parameters. The analysis shows that the fiber fuse is a new kind of solitary thermal shock wave in whose leading edge the temperature gradients can reach several thousand kelvins per micrometer.
TL;DR: It is shown that an optical pulse can propagate undistorted as a bright solitary wave in the normal dispersion regime when it couples through cross-phase modulation to a dark pulse in the anomalous dispersion regimes.
Abstract: We show that an optical pulse can propagate undistorted as a bright solitary wave in the normal dispersion regime when it couples through cross-phase modulation to a dark pulse in the anomalous dispersion regime.
TL;DR: This new photorefractive interaction is characterized by reasonable Phi* reflectivities (~10-25%), good Phi* fidelity, and no image cross talk.
Abstract: Two mutually incoherent extraordinary laser beams, incident upon opposite a faces of a BaTiO3 crystal, generate a set of photorefractive holograms that channel both beams toward the +c face of the crystal, where they are internally reflected into the opposite channel. The resultant cross coupling of the two incident beams produces a pair of phase-conjugate (ϕ*) beams. This new photorefractive interaction is characterized by reasonable ϕ* reflectivities (~10–25%), good ϕ* fidelity, and no image cross talk. The variations in ϕ* reflectivity with crystal orientation, angles of incidence, and intensity ratio are presented. The formation times of the photorefractive gratings responsible for the phase conjugation are significantly shorter than those of other self-pumped phase conjugators.
TL;DR: It is shown that at very low temperatures the steady-state photon statistics of the micromaser are stronglv influenced by the existence of trapping states, which are a true quantum effect resulting from the granulated character of the electromagnetic field.
Abstract: We show that at very low temperatures the steady-state photon statistics of the micromaser are strongly influenced by the existence of trapping states. The resulting resonances are a true quantum effect resulting from the granulated character of the electromagnetic field.
TL;DR: It is demonstrated theoretically that a nonlinear medium with a spatially periodic refractive index can support solitons of the nonlinear Schrodinger equation.
Abstract: It is demonstrated theoretically that a nonlinear medium with a spatially periodic refractive index can support solitons of the nonlinear Schrodinger equation.
TL;DR: In this article, a dual-polarization technique for reducing intermodulation distortion in integrated-optic interferometric modulators is described, which results in a decrease in modulator sensitivity.
Abstract: A dual-polarization technique for reducing intermodulation distortion in integrated-optic interferometric modulators is described. While this technique results in a decrease in modulator sensitivity, the intermodulation distortion can be significantly reduced for a given depth of optical modulation by adjusting the relative amounts of TE and TM optical power. Reductions in intermodulation distortion as high as 21 dB were demonstrated by means of this technique with a Ti:LiNbO(3) device.
TL;DR: It is shown that the host glass influences the excited-state absorption spectra and that P(2)O(5)- or A1(2]O(3)-codoped fibers are the preferred choice for 514.5-, 655-, or 807-nm pump wavelengths owing to reduced pump excited- state absorption.
Abstract: Ground-state and excited-state absorption spectra covering the wavelength range of 450–1050 nm are presented for erbium-doped silica fibers with four different core codopants: GeO2, GeO2/B2O3, GeO2/P2O5, and Al2O3. It is shown that the host glass influences the excited-state absorption spectra and that P2O5- or Al2O3-codoped fibers are the preferred choice for 514.5-, 655-, or 807-nm pump wavelengths owing to reduced pump excited-state absorption. However, excited-state absorption is still significant at the 807-nm wavelength. Pump wavelengths of 524, 532, and 980 nm appear ideal because of the strong ground-state absorption and lack of excited-state absorption.
TL;DR: The stability of the output light from a diode-pumped intracavity frequency-doubled Nd:YAG laser was studied and the coupling of the two orthogonal linearly polarized modes through a sum-frequency-generation process was analyzed.
Abstract: The stability of the output light from a diode-pumped intracavity frequency-doubled Nd:YAG laser was studied. An intracavity nonlinear crystal, such as Type II phase-matched potassium titanyl phosphate, was used for frequency doubling. The incident beam consisted of two orthogonal linearly polarized modes. When the polarization eigenvectors were parallel to the E and O axes of the crystal, a large amplitude fluctuation was observed; however, when the azimuthal angle between the polarization eigenvectors and the axis was 45°, the light output was stabilized. The experimental results are explained by analyzing the coupling of the two orthogonal linearly polarized modes through a sum-frequency-generation process.
TL;DR: In this article, a new type of electron-beam-addressed spatial light modulator has been demonstrated, based on the local tuning of an optothermal nonlinear interference filter by the scanned electron beam.
Abstract: A new type of electron-beam-addressed spatial light modulator has been demonstrated. It is based on the local tuning of an optothermal nonlinear interference filter by the scanned electron beam. Such an e-beam-tunable interference filter device should find applications in both display technology and optical data processing.
TL;DR: Direct measurements of the frequency dependence of the optical group delay for a number of optical components commonly used in femtosecond optics are reported, obtaining measurement accuracy of about ±1 fsec over the spectral range of 400–750 nm.
Abstract: We report direct measurements of the frequency dependence of the optical group delay for a number of optical components commonly used in femtosecond optics. We have investigated the group-delay errors that occur on reflection from metal and dielectric mirrors under various conditions and passage through devices that introduce angular dispersion. We obtain measurement accuracy of about ±1 fsec over the spectral range of 400–750 nm.
TL;DR: Computed Gaussian-beam results agree well with analytic plane-wave calculations that straddle Raman-Nath and Bragg regimes for counterpropagating waves in Kerr media for both focusing and defocusing nonlinearities.
Abstract: Continuous-wave and oscillatory transverse instabilities are predicted for counterpropagating waves in Kerr media for both focusing and defocusing nonlinearities. Neither a cavity nor a finite response time is required. Computed Gaussian-beam results agree well with analytic plane-wave calculations that straddle Raman-Nath and Bragg regimes.
TL;DR: This new method provides what is to the authors' knowledge the first complete physical description of the classical processes involved in cooperative EM scattering by an aggregate of spheres.
Abstract: An outline is provided of the derivation of an order-of-scattering technique that we apply here for the first reported time to the study of light scattering by two or more interacting spheres. This new method provides what is to our knowledge the first complete physical description of the classical processes involved in cooperative EM scattering by an aggregate of spheres. In addition, the algorithms that it employs are often more efficient than those used in an already established method. Comparisons between selected calculations and experimental results are made for linear chains of three and five spheres, and effects of particle orientation are investigated theoretically.
TL;DR: In this paper, the temporal response of a polarization-dispersive medium is derived for the case of a highly coherent source using principal states of polarization Experimental results in dispersion-shifted fiber at 155 μm confirm that the first-order effect of polarization dispersion is a difference in the time of flight for pulses launched in the two principal states, while the second-order effects on pulse propagation is an effective chromatic dispersion of opposite sign for these two states.
Abstract: The temporal response of a polarization-dispersive medium is derived for the case of a highly coherent source using principal states of polarization Experimental results in dispersion-shifted fiber at 155 μm confirm that the first-order effect of polarization dispersion is a difference in the time of flight for pulses launched in the two principal states, while the second-order effect on pulse propagation is an effective chromatic dispersion of opposite sign for these two states The latter effect is demonstrated by the compression of frequency-chirped pulses in one principal state and pulse broadening in the orthogonal state
TL;DR: It is observed that two-body collisions between cold sodium atoms confined within a magnetic-molasses optical trap lead to significant atomic-density-dependent trap losses that set an upper limit to the product of atomic density and confinement time that can be achieved in such a trap.
Abstract: We have observed that two-body collisions between cold sodium atoms confined within a magnetic-molasses optical trap lead to significant atomic-density-dependent trap losses. Such losses set an upper limit to the product of atomic density and confinement time that can be achieved in such a trap.
TL;DR: By using a Michelson interferometer arrangement, the phase shift experienced by a light beam whose state of polarization is made to follow, by successive unitary transformations, a closed circuit on the Poincare sphere is measured.
Abstract: By using a Michelson interferometer arrangement, we have measured the phase shift (the Pancharatnam phase) experienced by a light beam whose state of polarization is made to follow, by successive unitary transformations, a closed circuit on the Poincare sphere. We confirm that the phase shift equals half of the solid angle subtended by the closed circuit at the center of the sphere. This phase is closely related to the topological Berry phase.
TL;DR: Femtosecond measurements of coherent effects arising from exciton bleaching in bulk GaAs are reported and are shown to be a manifestation of the uncertainty relation in time-resolved spectroscopy.
Abstract: Femtosecond measurements of coherent effects arising from exciton bleaching in bulk GaAs are reported. This phenomenon, which is characterized by spectral oscillatory structures, is general and appears whenever the temporal resolution is shorter than the material coherence time. This is shown to be a manifestation of the uncertainty relation in time-resolved spectroscopy.