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Showing papers on "Single-mode optical fiber published in 2004"


Journal ArticleDOI
TL;DR: Air-clad subwavelength-diameter wires have interesting properties such as tight-confinement ability, enhanced evanescent fields and large waveguide dispersions that are very promising for developing future microphotonic devices with subwa wavelength-width structures.
Abstract: Single-mode optical wave guiding properties of silica and silicon subwavelength-diameter wires are studied with exact solutions of Maxwell's equations. Single mode conditions, modal fields, power distribution, group velocities and waveguide dispersions are studied. It shows that air-clad subwavelength-diameter wires have interesting properties such as tight-confinement ability, enhanced evanescent fields and large waveguide dispersions that are very promising for developing future microphotonic devices with subwavelength-width structures.

682 citations


Journal ArticleDOI
TL;DR: A high-efficiency broadband grating coupler for coupling between silicon-on-insulator (SOI) waveguides and optical fibers and the size of the grooves is optimized numerically.
Abstract: We have designed a high-efficiency broadband grating coupler for coupling between silicon-on-insulator (SOI) waveguides and optical fibers. The grating is only 13 µm long and 12 µm wide, and the size of the grooves is optimized numerically. For TE polarization the coupling loss to single-mode fiber is below 1 dB over a 35-nm wavelength range when using SOI with a two-pair bottom reflector. The tolerances to fabrication errors are also calculated.

676 citations


Journal ArticleDOI
TL;DR: The fusion-splicing of a bismuth holey fiber to silica fibers is demonstrated, which has resulted in reduced coupling loss and robust single mode guiding at 1550 nm.
Abstract: We report on the progress of bismuth oxide glass holey fibers for nonlinear device applications. The use of micron-scale core diameters has resulted in a very high nonlinearity of 1100 W-1 km-1 at 1550 nm. The nonlinear performance of the fibers is evaluated in terms of a newly introduced figure-of-merit for nonlinear device applications. Anomalous dispersion at 1550 nm has been predicted and experimentally confirmed by soliton self-frequency shifting. In addition, we demonstrate the fusion-splicing of a bismuth holey fiber to silica fibers, which has resulted in reduced coupling loss and robust single mode guiding at 1550 nm.

263 citations


Journal ArticleDOI
TL;DR: In this article, the authors suggest using a two-color evanescent light field around a subwavelength-diameter fiber to trap and guide atoms, which allows confinement of atoms to two straight lines parallel to the fiber axis.
Abstract: We suggest using a two-color evanescent light field around a subwavelength-diameter fiber to trap and guide atoms. The optical fiber carries a red-detuned light and a blue-detuned light, with both modes far from resonance. When both input light fields are circularly polarized, a set of trapping minima of the total potential in the transverse plane is formed as a ring around the fiber. This design allows confinement of atoms to a cylindrical shell around the fiber. When one or both of the input light fields are linearly polarized, the total potential has two local minimum points in the transverse plane. This design allows confinement of atoms to two straight lines parallel to the fiber axis. Due to the small thickness of the fiber, we can use far-off-resonance fields with substantially differing evanescent decay lengths to produce a net potential with a large depth, a large coherence time, and a large trap lifetime. For example, a 0.2-\ensuremath{\mu}m-radius silica fiber carrying 30 mW of 1.06-\ensuremath{\mu}m-wavelength light and 29 mW of 700-nm-wavelength light, both fields circularly polarized at the input, gives for cesium atoms a trap depth of 2.9 mK, a coherence time of 32 ms, and a recoil-heating-limited trap lifetime of 541 s.

251 citations


Journal ArticleDOI
TL;DR: This work reports on a polarization maintaining large mode area photonic crystal fiber, which is both single mode at any wavelength and have a practically constant birefringence for any wavelength.
Abstract: We report on a polarization maintaining large mode area photonic crystal fiber Unlike, previous work on polarization maintaining photonic crystal fibers, birefringence is introduced using stress applying parts This has allowed us to realize fibers, which are both single mode at any wavelength and have a practically constant birefringence for any wavelength The fibers presented in this work have mode field diameters from about 4 to 65 micron, and exhibit a typical birefringence of 15·10-4

168 citations


Journal ArticleDOI
TL;DR: In this paper, the authors studied the properties of the field in the fundamental mode HE11 of a vacuum-clad subwavelength-diameter optical fiber using the exact solutions of Maxwells equations.

168 citations


Journal ArticleDOI
TL;DR: It is demonstrated that with highly nonlinear dispersion shifted fiber (HNLF) fusion spliced directly to the amplifier output, the system generates a supercontinuum spectrum that spans more than an octave, with an average power 400 mW.
Abstract: We present a source of high power femtosecond pulses at 1550 nm with compressed pulses at the end of a single mode fiber (SMF) pigtail. The system generates 34 femtosecond pulses at a repetition rate of 46 MHz, with average powers greater than 400 mW. The pulses are generated in a passively modelocked, erbium-doped fiber laser, and amplified in a short, erbium-doped fiber amplifier. The output of the fiber amplifier consists of highly chirped picosecond pulses. These picosecond pulses are then compressed in standard single mode fiber. While the compressed pulses in the SMF pigtail do show a low pedestal that could be avoided with the use of bulk-optic compression, the desire to compress the pulses in SMF is motivated by the ability to splice the single mode fiber to a nonlinear fiber, for continuum generation applications. We demonstrate that with highly nonlinear dispersion shifted fiber (HNLF) fusion spliced directly to the amplifier output, we generate a supercontinuum spectrum that spans more than an octave, with an average power 400 mW. Such a high power, all-fiber supercontinuum source has many important applications including frequency metrology and bio-medical imaging.

158 citations


Journal ArticleDOI
TL;DR: The ultimate laser-induced damage threshold and practical limitations of current hollow-core fibers for the delivery of short optical pulses are discussed.
Abstract: We report on the development of hollow-core photonic bandgap fibers for the delivery of high energy pulses for precision micro-machining applications. Short pulses of (65ns pulse width) and energies of the order of 0.37mJ have been delivered in a single spatial mode through hollow-core photonic bandgap fibers at 1064nm using a high repetition rate (15kHz) Nd:YAG laser. The ultimate laser-induced damage threshold and practical limitations of current hollow-core fibers for the delivery of short optical pulses are discussed.

156 citations


Journal ArticleDOI
TL;DR: An electromagnetic field quadrature measurement, performed on one of the modes of the nonlocal single-photon state alpha|1,0>-beta|0,1>, collapses it into a superposition of the single- photon and vacuum states in the other mode, to implement remote preparation of arbitrary single-mode photonic qubits conditioned on observation of a preselected quadratures value.
Abstract: An electromagnetic field quadrature measurement, performed on one of the modes of the nonlocal single-photon state alpha|1,0>-beta|0,1>, collapses it into a superposition of the single-photon and vacuum states in the other mode. We use this effect to implement remote preparation of arbitrary single-mode photonic qubits conditioned on observation of a preselected quadrature value. The preparation efficiency of the resulting qubit can be higher than that of the initial single photon.

140 citations


Journal ArticleDOI
TL;DR: Broadband asymmetric spectral broadening is reported experimentally and found in fairly good agreement with a numerical Schrödinger simulation including a phase-diffusion model for the partially coherent beam.
Abstract: The nonlinear propagation of a partially coherent continuous-wave laser beam in single-mode optical fibers is investigated both theoretically and experimentally, with a special attention to the zero-dispersion wavelength region where modulation instability is expected. Broadband asymmetric spectral broadening is reported experimentally and found in fairly good agreement with a numerical Schrodinger simulation including a phase-diffusion model for the partially coherent beam. This model shows in addition that the underlying spectral broadening mechanism relies not only on modulation instability but also on the generation of high-order soliton-like pulses and dispersive waves. The coherence degradation which results from these ultrafast phenomena is confirmed by autocorrelation measurement.

140 citations


Journal ArticleDOI
TL;DR: In this article, a single-probe Michelson interferometer that uses mode coupling in a long-period grating to establish the two optical paths in a single optical fiber is presented.
Abstract: This paper presents a single-probe Michelson interferometer that uses mode coupling in a long-period grating to establish the two optical paths in a single optical fibre. The interferometer phase shift depends on the refractive index of the material that surrounds the fibre probe, with the phase sensitivity directly proportional to the probe length. A simple phenomenological model explains the experimental results obtained with a liquid level sensor and a refractive index sensor. Its temperature sensitivity depends on the type of fibre that constitutes the probe. With a 45 mm long fibre probe, it is −2.5 and 12.8 degrees °C−1 for normal single mode fibre (SMF28) and germanium–boron co-doped fibre (PS1500), respectively.

Journal ArticleDOI
TL;DR: In this paper, the effects of simulated Raman scattering (SRS) in ultra-high-Q (UHQ) surface-tension-induced spherical and chip-based toroid microcavities is considered both theoretically and experimentally.
Abstract: Stimulated Raman scattering (SRS) in ultrahigh-Q (UHQ) surface-tension-induced spherical and chip-based toroid microcavities is considered both theoretically and experimentally. These microcavities are fabricated from silica, exhibit small mode volume (typically 1000 /spl mu/m/sup 3/) and possess whispering-gallery type modes with long photon storage times (in the range of 100 ns), significantly reducing the threshold for stimulated nonlinear optical phenomena. Oscillation threshold levels of less than 100 /spl mu/W of launched fiber pump power, in microcavities with quality factors of 100 million are observed. Using a steady-state analysis of the coupled-mode equations for the pump and Raman whispering-gallery modes, the threshold, efficiencies and cascading properties of SRS in UHQ devices are derived. The results are experimentally confirmed in the telecommunication band (1550 nm) using tapered optical fibers as highly efficient waveguide coupling elements for both pumping and signal extraction. The device performance dependence on coupling, quality factor and modal volume are measured and found to be in good agreement with theory. This includes analysis of the threshold and efficiency for cascaded Raman scattering. The side-by-side study of nonlinear oscillation in both spherical microcavities and toroid microcavities on-a-chip also allows for comparison of their properties. In addition to the benefits of a wafer-scale geometry, including integration with optical, electrical, or mechanical functionality, microtoroids on-a-chip exhibit single mode Raman oscillation over a wide range of pump powers.

Journal ArticleDOI
TL;DR: In this paper, the authors present a successful design, realisation and characterisation of single-mode TE00-TM00 rib optical waveguides composed of SU-8 polymer.

Journal ArticleDOI
TL;DR: Eigenvalue equations for solving full-vector modes of optical waveguides are formulated using Yee-mesh-based finite difference algorithms and incorporated with perfectly matched layer absorbing boundary conditions to calculate the complex propagation constants and the confinement losses of leaky waveguide modes.
Abstract: Eigenvalue equations for solving full-vector modes of optical waveguides are formulated using Yee-mesh-based finite difference algorithms and incorporated with perfectly matched layer absorbing boundary conditions. The established method is thus able to calculate the complex propagation constants and the confinement losses of leaky waveguide modes. Proper matching of dielectric interface conditions through the Taylor series expansion of the fields is adopted in the formulation to achieve high numerical accuracy. The method is applied to the study of the holey fiber with triangular lattice, the two-core holey fiber, and the air-guiding photonic crystal fiber.

Journal ArticleDOI
TL;DR: In this paper, the effects of zero-dispersion wavelength (ZDWL) fluctuations on dual-pump fiber-optic parametric amplifiers are investigated analytically and numerically.
Abstract: Effects of zero-dispersion wavelength (ZDWL) fluctuations on dual-pump fiber-optic parametric amplifiers are investigated analytically and numerically. It is found that the signal gain varies considerably from fiber to fiber even though each fiber may have the same ZDWL on average. Moreover, the gain spectrum becomes highly nonuniform for a given fiber because of such dispersion fluctuations. Numerical simulations show that this problem can be solved to a large extent by reducing wavelength separation between the two pumps, but only at the expense of a reduced amplifier bandwidth.

Journal ArticleDOI
TL;DR: In this paper, a new type of the fiber-optic microsensor for surface plasmon resonance (SPR) was created on the basis of the fabrication technology of optical fiber probes in near-field scanning optical microscopy (NSOM).

Journal ArticleDOI
TL;DR: In this paper, the transmission performance of ultra-dense 2.5 and 10-Gb/s non-return-to-zero intensity-modulated direct-detection wavelength-division-multiplexing systems in various single-mode fibers is investigated.
Abstract: Transmission performance of ultra-dense 2.5- and 10-Gb/s nonreturn-to-zero intensity-modulated direct-detection wavelength-division-multiplexing systems in various single-mode fibers is investigated. Fundamental limiting factors and their remedies by using optimum dispersion compensation for periodically amplified systems in C band are presented.

Journal ArticleDOI
TL;DR: A high power/energy 19-core Yb-doped fiber amplifier that operates in its fundamental in-phase mode, theoretically and experimentally, and shows that, with a Gaussian beam as seed, the in- phase supermode dominates.
Abstract: We demonstrate, theoretically and experimentally, a high power/energy 19-core Yb-doped fiber amplifier that operates in its fundamental in-phase mode. The calculated result using an improved coupled mode theory with gain shows that, with a Gaussian beam as seed, the in-phase supermode dominates. Experimentally, we use a Q-switched single-core fiber laser with single transverse mode as seed, and amplify it with a 5.8 m 19-core fiber. The measured near and far fields are close to the in-phase supermode. The measured M2 factor of the amplified beam is 1.5, which is close to the theoretical value. A pulse energy gain of 20 dB is obtained with the amplified pulse energy up to 0.65 mJ at a repetition frequency of 5 kHz. No appreciable stimulated Brillouin scattering is observed at this power level.

Journal ArticleDOI
Ming Han1, Yan Zhang1, Fabin Shen1, Gary Pickrell1, Anbo Wang1 
TL;DR: A novel signal-processing algorithm for single-mode optical fiber extrinsic Fabry-Perot interferometric sensors that can achieve both high-resolution, absolute measurement of the cavity length and a large dynamic measurement range simultaneously simultaneously is presented.
Abstract: We present a novel signal-processing algorithm for single-mode optical fiber extrinsic Fabry–Perot interferometric sensors that can achieve both high-resolution, absolute measurement of the cavity length and a large dynamic measurement range simultaneously. The algorithm is based on an accurate model of the characteristics of a fiber-optic sensor that takes into account the phase shift that is due to the coupling of light reflected at the second surface to the lead-in fiber end.

Proceedings ArticleDOI
TL;DR: In this article, multimode fused fiber bundle combiners with or without signal fiber feed-through, Bragg gratings and mode field adaptors are used to couple several fiber pigtailed pump diodes to a double-clad fiber.
Abstract: Fiber lasers have shown extraordinary progress in power level, reaching the kilowatt range. These results were achieved with large mode area fibers pumped with high power laser diodes coupled with bulk-optics. To enable the commercial development of these high power fiber lasers, we have demonstrated several All-Fiber components, which replace the bulk-optic interface in the present laser configurations. These components include multimode fused fiber bundle combiners with or without signal fiber feed-through, Bragg gratings and mode field adaptors. The multimode fibers are used to couple several fiber pigtailed pump diodes to a double-clad fiber. Such combiners may contain a signal fiber to provide an input or output for the core modes of the double-clad fiber. Mode field adaptors perform fundamental mode matching between different core fibers. Bragg gratings are used as reflectors for the laser cavity. These components exhibit low-loss and high power handling of 200 Watts has been demonstrated. They enable the design of true high power single-mode All-Fiber lasers that will be small, rugged and reliable.

DissertationDOI
01 Jan 2004
TL;DR: In this article, the nonlinear optical properties of toroidally silica microcavities have been investigated and it is shown that these cavities can exhibit ultra-high-Q whispering-gallery modes, allowing to achieve ultra high-Q modes on a chip.
Abstract: Optical microcavities confine light at resonant frequencies for extended periods of time and fundamentally alter the interaction of light with matter. They are the basis of numerous applied and fundamental studies, such as cavity QED, photonics and sensing. Of all resonant geometries, surface tension-induced microcavities, such as silica micro-spheres, exhibit the highest Q-factor to date of nearly 9 billion. Despite these high Q-factor and the intense interest in these structures, the nonlinear optical properties of silica micro-spheres have remained nearly entirely unexplored. In this thesis the nonlinear optical phenomena which can occur in ultra-high-Q microcavities are investigated. To efficiently excite the whispering-gallery modes, tapered optical fibers are used and the coupling to ultra-high-Q modes studied. It is found, that microcavities with ultra-high enter a regime where scattering of light into the degenerate pair of clockwise and counter-clockwise mode is the dominant scattering process. In this regime the coupling properties are significantly altered, but the cavities still retain their ability to achieve significant cavity build-up fields. This allowed exceeding the threshold for all common nonlinearities encountered in silica. In particular, stimulated Raman scattering is observed in taper fiber coupled silica micro-spheres at threshold levels typically in the micro-Watt range, which usually is considered the regime of linear optics. Cascaded Raman lasing is also observed in these structures. The tapered optical fiber in these experiments functions to both pump WGMs as well as to extract the nonlinear Raman fields. In addition, the tapered-fiber coupling junction is highly ideal, making it possible to strongly over-couple ultra-high-Q cavities with negligible junction loss. This feature allows for the observation of very high internal differential photon conversion efficiencies approaching unity. Whereas micro-spheres are both compact and efficient nonlinear oscillators, their fabrication properties lack the control and parallelism typical of micro-fabrication techniques. A synergistic approach of micro-fabrication and a laser assisted reflow process, allows to create toroidally silica microcavities on a chip. In this thesis it is demonstrated, that these cavities can exhibit ultra-high-Q whispering-gallery modes, allowing to achieve ultra-high-Q modes on a chip. This results is a nearly four-order of magnitude improvement with respect to other wafer-scale microcavities. In addition their azimuthal mode-spectrum is strongly reduced. Nonlinear oscillation in these cavities has also been studied, and stimulated Raman scattering observed, allowing to achieve the first Raman laser on a chip. The devices show improved performance compared to micro-spheres due to a strongly reduced azimuthal mode spectrum, which allowed to observe single mode emission. The enhanced geometric control of these cavities is also studied and found to profoundly alter the nonlinear optical processes the toroid microcavities. Reduction of toroidal cross section is observed to cause a transition from stimulated Raman to parametric oscillation regime. This allowed to observe Kerr nonlinearity induced parametric oscillation in a microcavity for the first time. The parametrically generated "twin beams" exhibit high conversion efficiency and show near unity signal-to-idler ratio.

Proceedings ArticleDOI
K. Shaneman1, S. Gray1
31 Oct 2004
TL;DR: In this paper, the authors quantified the bend loss required to tap a signal propagating in a single mode fiber and analyzed the properties of the bend that could be used to detect that a tap is occurring.
Abstract: Increasing emphasis on reliable data transmission for homeland security and network-centric operations makes secure communications a critical component of national security. While fiber optic cables are immune to typical EMI/RFI issues, it is possible to intercept an optical signal successfully if risk areas are not understood and if detection and/or prevention mechanisms are not actively integrated into network management practices. There are several ways to 'tap' into an optical fiber, including fiber bending, splitting, evanescent coupling, scattering, and V-grooves. Many of these techniques require altering the physical characteristics of the fiber with a significant risk of damaging the fiber and having the optical intercept detected by the end user. Of all the techniques, the bent fiber tap is the most easily deployed with minimal risk of damage or detection. The paper quantifies the bend loss required to tap a signal propagating in a single mode fiber and analyzes the properties of the bend that could be used to detect that a tap is occurring. Understanding the mechanisms used for fiber tapping provides greater insight into ways of actively detecting unauthorized optical intercepts or compromised network security. Enhanced monitoring techniques enable the detection and localization of fiber taps. Monitoring techniques are reviewed with detailed analysis of each method's effectiveness in detecting bent fiber taps and their cost-effectiveness for integration into optical networks.

Journal ArticleDOI
TL;DR: In this article, the authors presented the design and experimental results of a novel overmoded slow-wave high-power microwave (HPM) generator that is featured by its compactness, low-operation magnetic field, and potentially high power and high efficiency.
Abstract: We present the design and experimental results of a novel overmoded slow-wave high-power microwave (HPM) generator that is featured by its compactness, low-operation magnetic field, and potentially high power and high efficiency. The device includes two slow-wave structure (SWS) sections, a resonant cavity, and a tapered waveguide. The resonant cavity was well designed and was used to achieve the axial mode selection and to decrease the length of the SWS sections. The radial mode selection is achieved using the property of "surface wave" of the device to excite the TM/sub 01/ mode while making the higher TM/sub 0n/ modes unexcited. The physical mechanisms of axial and radial mode selections ensure that the microwave is produced with a single mode and a narrow band. The feasibility of low magnetic field operation is also investigated based on the characteristics of the overmoded slow-wave devices. Experiments were carried out at the Spark-2 accelerator. At diode voltage of 474 kV, beam current of 5.2 kA, and guiding magnetic field strength of 0.6 T, a microwave was generated with power of 510 MW, mode of TM/sub 01/, and frequency of 9.54 GHz. The relative half width of the frequency spectrum is /spl Delta/f/f= 0.6%, and the beam-to-microwave efficiency is about 21% in our experiment.

Journal ArticleDOI
TL;DR: Comment on the recent Letter by Jiao et al. in which a polarization-sensitive optical coherence tomography system was presented, finding that Interrogating a sample with two orthogonal incident polarization states cannot always recover birefringence correctly.
Abstract: We comment on the recent Letter by Jiao et al. [Opt. Lett. 28, 1206 (2003)] in which a polarization-sensitive optical coherence tomography system was presented. Interrogating a sample with two orthogonal incident polarization states cannot always recover birefringence correctly. A previously presented fiber-based polarization-sensitive system was inaccurately characterized, and its method of eliminating the polarization distortion caused by single-mode optical fiber was presented earlier by Saxer et al. [Opt. Lett. 25, 1355 (2000)].

Journal ArticleDOI
16 May 2004
TL;DR: In this article, a single-mode operation at 4.4 THz is obtained from distributed-feedback quantum-cascade lasers with complex-coupling metallic gratings.
Abstract: Single-mode operation at 4.4 THz is obtained from distributed-feedback quantum-cascade lasers with complex-coupling metallic gratings. The emission shows a stable side-mode suppression of more than 20 dB at all injection currents and operating temperatures

Journal ArticleDOI
TL;DR: In this article, an all-optical 2R regenerator at 40 Gb/s that is based on self-phase modulation in fiber is presented, and the effect of fiber length, launch power into the fiber, and regenerator filter offset on the regenerator performance is investigated.
Abstract: Optimization of an all-optical 2R regenerator at 40 Gb/s that is based on self-phase modulation in fiber is presented. The effect of fiber length, launch power into the fiber, and regenerator filter offset on the regenerator performance are investigated. We show that all three parameters can be carefully chosen to maximize the pulse regeneration. When optimized, we demonstrate an improvement in Q value of 1.5 dB.

Journal ArticleDOI
TL;DR: The spectral attenuation, single-turn bend loss, and mode-field diameters are measured and the PCF is found to have a significantly larger bandwidth than the SMF for an identical MFD.
Abstract: We experimentally compare the optical bandwidth of a conventional single-mode fiber (SMF) with 3 different photonic crystal fibers (PCF) all optimized for visible applications. The spectral attenuation, single-turn bend loss, and mode-field diameters (MFD) are measured and the PCF is found to have a significantly larger bandwidth than the SMF for an identical MFD. It is shown how this advantage can be utilized for realizing a larger MFD for the PCF while maintaining a bending resistant fiber.

Journal ArticleDOI
TL;DR: Srinivasan et al. as discussed by the authors used fiber taper waveguides formed from standard silica single-mode optical fibers to evanescently couple light into the guided modes of a patterned silicon membrane.
Abstract: The demonstration of an optical fiber based probe for efficiently exciting the waveguide modes of high-index contrast planar photonic crystal (PC) slabs is presented. Fiber taper waveguides formed from standard silica single-mode optical fibers are used to evanescently couple light into the guided modes of a patterned silicon membrane. A coupling efficiency of ~95% is obtained between the fiber taper and a PC waveguide mode suitably designed for integration with a previously studied ultrasmall mode volume high-Q PC resonant cavity [Srinivasan et al., Appl. Phys. Lett. 83, 1915 (2003)]. The micron-scale lateral extent and dispersion of the fiber taper is used as a near-field spatial and spectral probe to study the profile and dispersion of PC waveguide modes.

Journal ArticleDOI
TL;DR: In this article, a 9.3-W continuous-wave 1535-nm multimode output from a 7.0-cm short-length Er-Yb codoped phosphate fiber laser was achieved.
Abstract: We generate 9.3-W continuous-wave 1535-nm multimode output from a 7.0-cm short-length Er-Yb codoped phosphate fiber laser. A slope efficiency of 29% is obtained at pump powers below 27 W. Very high output power per unit fiber length of 1.33 W/cm is achieved. From another 7.1-cm Er-Yb codoped fiber laser, 4.0-W single-transverse-mode output with M/sup 2//spl ap/1.1 is generated.

Journal ArticleDOI
TL;DR: In this article, the modal characteristics of large-cross-section silicon-on-insulator-based rib waveguides are analyzed and it is shown that satisfying widely used design criteria is not sufficient to ensure single-mode behavior.
Abstract: Results from detailed numerical analyses of the modal characteristics of large-cross-section silicon-on-insulator-based rib waveguides are presented. They highlight for the first time that satisfying widely used design criteria is not sufficient to ensure single-mode behavior. In particular, the geometries that the design formulas predict should be single-mode are shown to support higher order vertical modes that do not couple (leak) into the outer slab region and are thus low loss in nature. Fortunately, a wide range of practical rib geometries still remains for which the leakage loss of modes other than those of EH/sub 00/ and HE/sub 00/ is sufficiently high to make the waveguides effectively single mode for each polarization.