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Showing papers on "Radiation mode published in 2013"


Journal ArticleDOI
TL;DR: A fiber laser design that is capable of producing switchable transverse modes through wavelength tuning and adding polarization controllers in the laser cavity, output modes with cylindrical vector polarization are realized.
Abstract: We report a fiber laser design that is capable of producing switchable transverse modes through wavelength tuning. The transverse mode switching is realized by exploiting the particular transverse mode-wavelength association characteristics of the few-mode fiber Bragg grating. Different transverse mode outputs with high spatial mode quality can be obtained by adjusting the oscillating wavelength with a tunable filter within the fiber laser cavity. For each of the spatial mode outputs, the laser operates at the corresponding single wavelength with narrow linewidth. Through adding polarization controllers in the laser cavity, output modes with cylindrical vector polarization are also realized.

82 citations


Journal ArticleDOI
TL;DR: An approach to actively stabilize the beam profile of a fiber amplifier above the mode instability threshold is demonstrated and the beam quality and the pointing stability are significantly increased at power levels of up to three times the mode instabilities threshold.
Abstract: We demonstrate an approach to actively stabilize the beam profile of a fiber amplifier above the mode instability threshold. Both the beam quality and the pointing stability are significantly increased at power levels of up to three times the mode instabilities threshold. The physical working principle is discussed at the light of the recently published theoretical explanations of mode instabilities.

81 citations


Journal ArticleDOI
TL;DR: In this article, a plasmonic coupling to a thin gold coating on the surface of the fiber modifies the effective indices of the modes differently according to polarization and to mode order.
Abstract: The high-order cladding modes of conventional single mode fiber come in semi-degenerate pairs corresponding to mostly radially or mostly azimuthally polarized light. Using tilted fiber Bragg gratings to excite these mode families separately, we show how plasmonic coupling to a thin gold coating on the surface of the fiber modifies the effective indices of the modes differently according to polarization and to mode order. In particular, we show the existence of a single “apolarized” grating resonance, with equal effective index for all input polarization states. This special resonance provides direct evidence of the excitation of a surface plasmon on the metal surface but also an absolute wavelength reference that allows for the precise localization of the most sensitive resonances in refractometric and biochemical sensing applications. Two plasmon interrogation methods are proposed, based on wavelength and amplitude measurements. Finally, we use a biotin-streptavidin biomolecular recognition experiment to demonstrate that differential spectral transmission measurements of a fine comb of cladding mode resonances in the vicinity of the apolarized resonance provide the most accurate method to extract information from plasmon-assisted Tilted fiber Bragg gratings, down to pM concentrations and at least 10−5 refractive index changes.

77 citations


Journal ArticleDOI
TL;DR: In this paper, the properties of the modes supported by the hybrid plasmonic waveguide consisting of a metal surface separated from a high-index slab by a low-index spacer are investigated.
Abstract: We investigate the properties of the modes supported by the hybrid plasmonic waveguide consisting of a metal surface separated from a high-index slab by a low-index spacer. We examine the variations of the effective mode indices and field profiles of the hybrid modes for various choices of waveguide dimensions. We show that the observed variations of the modal properties can be explained from the fact that these modes result from the coupling of the surface plasmons, supported by the metal-dielectric interface, and the dielectric waveguide mode, supported by the high-index slab. The method of analysis is very general and can be used to explain the modal properties of the hybrid plasmonic waveguides for a wide range of material properties and waveguide dimensions.

66 citations


Journal ArticleDOI
TL;DR: In this article, an attractive alternative for selective mode excitation in multimode fiber (MMF) using solid-core photonic crystal fiber (PCF) was presented, where the power coupling efficiency, differential mode delay, and bit error rate performance of several structural designs of solid core PCF waveguides were investigated for the selective excitation of mode LP01 in a MMF.
Abstract: To address the overwhelming bandwidth increase in premise backbones, an attractive alternative for selective mode excitation in multimode fiber (MMF) using solid-core photonic crystal fiber (PCF) is presented. The power coupling efficiency, differential mode delay, and bit-error rate performance of several structural designs of solid-core PCF waveguides are investigated for the selective excitation of mode LP01 in a MMF. The achieved coupling efficiency into mode LP01 is above 90% for PCF profiles with seven rings.

50 citations


Journal ArticleDOI
TL;DR: In this paper, the resonant mode characteristics of the nanoscale surface plasmon polaritons (SPP) waveguide filter with rectangle cavity were studied theoretically using the finite difference time domain method, both the band-stop-and band-pass-type rectangle SPP filters are analyzed.
Abstract: The resonant mode characteristics of the nanoscale surface plasmon polaritons (SPP) waveguide filter with rectangle cavity are studied theoretically. By using the finite difference time domain method, both the band-stop- and band-pass-type rectangle SPP filters are analyzed. The results show that the whispering gallery mode (WGM) and the Fabry–Perot (FP) mode can be supported by the rectangle SPP resonator. Furthermore, both traveling-wave mode and standing-wave mode can be realized by the WGM, while only standing-wave mode can be introduced by the FP mode. The traveling-wave mode can only be realized by the square-shaped SPP resonator, and the traveling-wave mode is splitted into two standing-wave modes by transforming the cavity shape from square to rectangle. Also, the effects of the cavity shape, cavity size, and coupling gap size on the transmission spectra of the SPP resonators are analyzed in detail. This simple SPP waveguide filter is very promising for the high-density SPP waveguide integrations.

49 citations


Journal ArticleDOI
TL;DR: It is found that the refractive index sensor based on grating-assisted light coupling between a strip waveguide and a slot waveguide can achieve extraordinarily high sensitivity when the group indices of two waveguides are close.
Abstract: In this paper, we present a design of a refractive index sensor based on grating-assisted light coupling between a strip waveguide and a slot waveguide. The slot waveguide serves as the sensing waveguide while the strip waveguide is used for light launching and detection. The wavelength at which the light is coupled from the strip waveguide to the slot waveguide serves as a measure of the refractive index of the external medium. The sensitivity of the sensor is ~1.46 × 10(3) nm/RIU (refractive index unit) and can be almost doubled by isolating the strip waveguide from the external medium. The effects of the slot-waveguide parameters on the sensitivity have also been investigated. In particular, it is found that the sensor can achieve extraordinarily high sensitivity (on the order of 10(5) nm/RIU) when the group indices of two waveguides are close. The temperature dependence of the sensor is also investigated and a sensor with very low temperature dependence can be achieved with a polymer isolation layer.

47 citations


Journal ArticleDOI
TL;DR: It is shown that the nonlocal effects give some new fundamental limitation on the confinement, leaving the mode area finite even for geometries with infinitely sharp tips, in a novel silicon hybrid plasmonic waveguide.
Abstract: The effect of nonlocal optical response is studied for a novel silicon hybrid plasmonic waveguide (HPW). Finite element method is used to implement the hydrodynamic model and the propagation mode is analyzed for a hybrid plasmonic waveguide of arbitrary cross section. The waveguide has an inverted metal nano-rib over a silicon-on-insulator (SOI) structure. An extremely small mode area of~10−6λ2 is achieved together with several microns long propagation distance at the telecom wavelength of 1.55μm. The figure of merit (FoM) is also improved in the same time, compared to the pervious hybrid plasmonic waveguide. We demonstrate the validity of our method by comparing our simulating results with some analytical results for a metal cylindrical waveguide and a metal slab waveguide in a wide wavelength range. For the HPW, we find that the nonlocal effects can give less loss and better confinement. In particular, we explore the influence of the radius of the rib’s tip on the loss and the confinement. We show that the nonlocal effects give some new fundamental limitation on the confinement, leaving the mode area finite even for geometries with infinitely sharp tips.

46 citations


Journal ArticleDOI
TL;DR: In this paper, the surface plasmon modes in a double-nanowire system were analyzed by employing the eigenmode analysis approach based on the finite element method and the dispersion relations, surface charge distributions, field patterns and propagation lengths of ten lowest energy plasmmon modes were presented.
Abstract: We study the surface plasmon modes in a silver double-nanowire system by employing the eigenmode analysis approach based on the finite element method. Calculated dispersion relations, surface charge distributions, field patterns and propagation lengths of ten lowest energy plasmon modes in the system are presented. These ten modes are categorized into three groups because they are found to originate from the monopole-monopole, dipole-dipole and quadrupole-quadrupole hybridizations between the two wires, respectively. Interestingly, in addition to the well studied gap mode (mode 1), the other mode from group 1 which is a symmetrically coupled charge mode (mode 2) is found to have a larger group velocity and a longer propagation length than mode 1, suggesting mode 2 to be another potential signal transporter for plasmonic circuits. Scenarios to efficiently excite (inject) group 1 modes in the two-wire system and also to convert mode 2 (mode 1) to mode 1 (mode 2) are demonstrated by numerical simulations.

40 citations


Journal ArticleDOI
21 Jan 2013-Sensors
TL;DR: The QCL mode results perfectly matched to the hybrid HE11 waveguide mode and the higher losses TE-like modes have efficiently suppressed by the deposited inner dielectric coating.
Abstract: We report on single mode optical transmission of hollow core glass waveguides (HWG) coupled with an external cavity mid-IR quantum cascade lasers (QCLs). The QCL mode results perfectly matched to the hybrid HE11 waveguide mode and the higher losses TE-like modes have efficiently suppressed by the deposited inner dielectric coating. Optical losses down to 0.44 dB/m and output beam divergence of ~5 mrad were measured. Using a HGW fiber with internal core size of 300 µm we obtained single mode laser transmission at 10.54 µm and successful employed it in a quartz enhanced photoacoustic gas sensor setup.

39 citations


Journal ArticleDOI
TL;DR: The broadband OCR investigated in the chalcogenide waveguide may find applications in on-chip wavelength conversion and near-infrared pulse generation.
Abstract: We propose an approach for an efficient generation of optical Cherenkov radiation (OCR) in the near-infrared by tailoring the waveguide dispersion for a zero group-velocity mismatching between the radiation and the pump soliton. Based on an As2S3 slot waveguide with subwavelength dimensions, dispersion profiles with four zero dispersion wavelengths are found to produce a phase-matching nonlinear process leading to a broadband resonant radiation. The broadband OCR investigated in the chalcogenide waveguide may find applications in on-chip wavelength conversion and near-infrared pulse generation.

Journal ArticleDOI
Qirong Xiao1, Xiao Chen1, Haichui Ren1, Ping Yan1, Mali Gong1 
TL;DR: A pump/signal fiber coupler with functions of pump light coupling and high- order-mode suppression is reported, which can prevent mode distortion with fundamental mode launching, and improve the fiber laser beam quality with high-order-mode launching.
Abstract: A pump/signal fiber coupler with functions of pump light coupling and high-order-mode suppression is reported. This coupler is composed of pump fibers and a double-clad fiber (DCF) with high pump-coupling efficiency. The core of DCF is microdeformed in the coupling region, which serves mode selection. Theoretical analysis and experimental results verify these functions. In the experiment, the pump-coupling and signal-transmitting efficiency of the coupler were ∼98% and ∼96%, respectively. This coupler can prevent mode distortion with fundamental mode launching, and improve the fiber laser beam quality with high-order-mode launching.

Proceedings ArticleDOI
TL;DR: In this article, the authors analyzed the most common sources of mode coupling and their e ects, which would lead to the development of more accurate propagation models and optimized multi-mode optical bers designs.
Abstract: The steady increase of bandwidth demand in worldwide communications has revived the interest about multimode optical bers and their use in spatial division multiplexed systems. Roughly speaking, in these systems transmission capacity is increased by using modes as separate channels, resorting to either special ber with negligible mode coupling, or to MIMO technology to compensate mode dispersion. In this framework, understanding the mechanisms that originate mode coupling is of crucial importance, for it would lead to the development of more accurate propagation models and optimized ber designs. The paper analyzes the most common sources of mode coupling and their e ects.

Journal ArticleDOI
TL;DR: The model results indicate that synchronism and wavestructure matching is associated with energy transfer through the step transition, and that the energy of an incident wave mode in a single layer is transmitted almost entirely to the associated mode-pair, where one exists.
Abstract: Ultrasonic guided wave inspection of structures containing adhesively bonded joints requires an understanding of the interaction of guided waves with geometric and material discontinuities or transitions in the waveguide. Such interactions result in mode conversion with energy being partitioned among the reflected and transmitted modes. The step transition between an aluminum layer and an aluminum-adhesive-aluminum multi-layer waveguide is analyzed as a model structure. Dispersion analysis enables assessment of (i) synchronism through dispersion curve overlap and (ii) wavestructure correlation. Mode-pairs in the multi-layer waveguide are defined relative to a prescribed mode in a single layer as being synchronized and having nearly perfect wavestructure matching. Only a limited number of mode-pairs exist, and each has a unique frequency range. A hybrid model based on semi-analytical finite elements and the normal mode expansion is implemented to assess mode conversion at a step transition in a waveguide. The model results indicate that synchronism and wavestructure matching is associated with energy transfer through the step transition, and that the energy of an incident wave mode in a single layer is transmitted almost entirely to the associated mode-pair, where one exists. This analysis guides the selection of incident modes that convert into transmitted modes and improve adhesive joint inspection with ultrasonic guided waves.

Journal ArticleDOI
TL;DR: The effective nonlinear coefficient of a waveguide mode can be written as the product of a suitable average of the nonlinear coefficients of the waveguide's constituent materials, the mode's group velocity and a new suitably defined effective mode area.
Abstract: We resolve the ambiguity in existing definitions of the effective area of a waveguide mode that have been reported in the literature by examining which definition leads to an accurate evaluation of the effective Kerr nonlinearity. We show that the effective nonlinear coefficient of a waveguide mode can be written as the product of a suitable average of the nonlinear coefficients of the waveguide’s constituent materials, the mode’s group velocity and a new suitably defined effective mode area. None of these parameters on their own completely describe the strength of the nonlinear effects of a waveguide.

Journal ArticleDOI
TL;DR: A general model is proposed to describe thermal-induced mode distortion in the step-index fiber (SIF) high power lasers and suggests that fiber with large mode area is more sensitive on the thermally induced mode distortion and hence is disadvantaged in keeping the beam quality in high power operation.
Abstract: A general model is proposed to describe thermal-induced mode distortion in the step-index fiber (SIF) high power lasers. Two normalized parameters in the model are able to determine the mode characteristic in the heated SIFs completely. Shrinking of the mode fields and excitation of the high-order modes by the thermal-optic effect are investigated. A simplified power amplification model is used to describe the output power redistribution under various guiding modes. The results suggest that fiber with large mode area is more sensitive on the thermally induced mode distortion and hence is disadvantaged in keeping the beam quality in high power operation. The model is further applied to improve the power scaling analysis of Yb-doped fiber lasers. Here the thermal effect is considered to couple with the optical damage and the stimulated Raman scattering dynamically, whereas direct constraint from the thermal lens is relaxed. The resulting maximal output power is from 67kW to 97kW, depending on power fraction of the fundamental mode.

Journal ArticleDOI
TL;DR: A cavity-resonator-integrated guided-mode resonance filter (CRIGF) consisting of a grating coupler and a pair of distributed Bragg reflectors in a channel waveguide is proposed for a narrow-band reflection spectrum with a small aperture.
Abstract: A cavity-resonator-integrated guided-mode resonance filter (CRIGF) consisting of a grating coupler and a pair of distributed Bragg reflectors in a channel waveguide is proposed for a narrow-band reflection spectrum with a small aperture. A channel waveguide structure and grating pattern of the device were simultaneously formed by the electron-beam direct-writing lithography. A full-width at half-maximum of reflection spectrum of the fabricated CRIGF was about 0.3 nm with the maximum reflectance of about 30%. A reflection phase varied by almost 2 for wavelength change of 1 nm.

Journal ArticleDOI
TL;DR: A large mode area at bent state and low sensitivity of bending orientation make the fiber of great potential in high-power fiber lasers.
Abstract: In view of its feasibility for fabrication and application, a bend-resistant large-mode-area photonic crystal fiber with a triangular core is proposed. In our design, the fiber proposes a solution to the issue of bend distortion. The mode field area of the fundamental mode at the wavelength of 1.064 μm achieves 930 μm2 at the straight state and 815 μm2 at a bending radius of 30 cm, respectively. The decrement of the mode field area at the bend state is only 12.473% compared to the straight state. Furthermore, when the fiber is bent with a bending radius of 30 cm, numerical results demonstrate that the fiber conforms to single-mode operation conditions and the bending orientation angle can be extended to ±55°. A large mode area at bent state and low sensitivity of bending orientation make the fiber of great potential in high-power fiber lasers.

Journal ArticleDOI
TL;DR: In this article, an antenna radiation method for exciting a dipole-type radiation mode in the ground plane of mobile devices is proposed based on a capacitively loaded slot placed at the centre of the groundplane.
Abstract: An innovative antenna radiation method for exciting a dipole-type radiation mode in the ground plane of mobile devices is proposed. This method is based on a capacitively loaded slot placed at the centre of the ground plane. The ground plane is 50 × 15 mm in length and width, respectively, which is the size typically used in USB dongles and headsets. The −10 dB impedance bandwidth is 12.9% at 2.4 GHz, fully covering the WiMax, Wi-Fi and Bluetooth frequency bands.

Journal ArticleDOI
TL;DR: In this article, a method on electromagnetic mode analysis in overmoded structure terahertz source is studied based on Fourier-Bessel series and particle-in-cell simulation.
Abstract: A method on electromagnetic mode analysis in overmoded structure terahertz source is studied in this paper. This mode analysis method is based on Fourier-Bessel series and the particle-in-cell simulation. The result of mode analysis shows that there are TM02 and TM03 modes present in the waveguide motivated by mode change in the discontinuity. The mode content keeps stable when the device starts to work. The magnetic field and the voltage of beam do not change the mode content to some extent. The parameters of diode affect the mode content significantly.

Journal ArticleDOI
TL;DR: The distinct disperion properties of higher-order modes in optical fibers permit the nonlinear generation of radiation deeper into the ultraviolet than is possible with the fundamental mode, exploited using adiabatic, broadband mode convertors.
Abstract: The distinct disperion properties of higher-order modes in optical fibers permit the nonlinear generation of radiation deeper into the ultraviolet than is possible with the fundamental mode. This is exploited using adiabatic, broadband mode convertors to couple light efficiently from an input fundamental mode and also to return the generated light to an output fundamental mode over a broad spectral range. For example, we generate visible and UV supercontinuum light in the LP02 mode of a photonic crystal fiber from sub-ns pulses with a wavelength of 532 nm.

Patent
27 Feb 2013
TL;DR: In this article, the authors describe photonic integrated circuits (PICs) for accomplishing polarization splitting and rotation using a first waveguide to receive light comprising orthogonally polarized transverse electric (TE) and transverse magnetic (TM) modes, and a reverse taper-shaped side to adiabatically receive one of the polarization modes (e.g., the TE mode) of the received light from the first-waveguide.
Abstract: Embodiments of the invention describe photonic integrated circuits (PICs) for accomplishing polarization splitting and rotation. Embodiments of the invention include a first waveguide to receive light comprising orthogonally polarized transverse electric (TE) and transverse magnetic (TM) modes, and a second waveguide disposed below the first waveguide and comprising a reverse taper-shaped side to adiabatically receive one of the polarization modes (e.g., the TE mode) of the received light from the first waveguide. Said horizontal offset between the first and the reverse taper-shaped side of the second waveguide comprises an offset such that, for example, the TM mode of the received light is rotated to a TE mode in the first waveguide. The above described offsets and taper shaped structures may also be used in an optical combiner.

Journal ArticleDOI
TL;DR: In this article, a Thermally expanded core (TEC) technique was introduced to realize mode field adaptation between single-mode fiber (SMF) and large mode area (LMA) fiber.
Abstract: The main source of light transmission loss between single-mode fiber (SMF) and large mode area (LMA) fiber is from the mode field mismatch. Thermally expanded core (TEC) technique was introduced to realize mode field adaptation between them. The SMF was heated by a H2–O2 flame to increase the mode field diameter (MFD) which can result in a mode field match with LMA. Both numerical calculation and experiment results show it is workable to realize mode field adaptation and get a low transmission loss by this method. For HI1060 (d=5 μm, NA=0.14) and LMA-GDF-15/130(d=15 μm, NA=0.08), a low-loss with 0.4 dB was obtained for SMF–LMA–SMF from 6.4 dB with TEC processing experimentally.

Journal ArticleDOI
TL;DR: UV four-wave mixing in the LP(02) mode of a photonic crystal fiber when pumped by a frequency-doubled 532 nm microchip laser in the normal dispersion regime is reported.
Abstract: We report UV four-wave mixing in the LP(02) mode of a photonic crystal fiber when pumped by a frequency-doubled 532 nm microchip laser in the normal dispersion regime. A pure LP(02) mode was generated for the pump light by a broadband all-fiber mode converter. Ultraviolet signal wavelengths as short as 342 nm were generated.

Journal ArticleDOI
TL;DR: In this paper, a bending orientation insensitive large mode area photonic crystal fiber with triangular core is proposed, which achieves single mode operation under any bending orientation angle at the bending radius of 30 cm.
Abstract: In view of the feasibility of fabrication and application, a bending orientation insensitive large mode area photonic crystal fiber with triangular core is proposed. This fiber structure breaks the limit of bend orientation angle and realizes single mode operation under any bending orientation angle at the bending radius of 30 cm. The mode field area of the fundamental mode at the wavelength of 1.064 μm achieves 1386 μm2 at the straight state and 1154 μm2 at a bending radius of 30 cm, respectively. The decrement of the mode field area at the bent state is only 16.85% compared to that at the straight state. The large mode area at the bent state, small decrement of the mode field area, and low sensitivity of bending orientation make the fiber of great potential in compact high power fiber lasers.

Patent
02 Sep 2013
TL;DR: In this paper, a polarization conversion element is disclosed in which an optical waveguide formed on a substrate sequentially includes a first waveguide, a polarization rotation portion, and a second waveguide portion.
Abstract: A polarization conversion element is disclosed in which an optical waveguide formed on a substrate sequentially includes a first waveguide portion, a polarization rotation portion, and a second waveguide portion, an effective refractive index of a TE mode having the highest effective refractive index in an eigen mode of waveguide light on a sectional surface of the first waveguide portion is higher than an effective refractive index of a TM mode having the highest effective refractive index, an effective refractive index of the TM mode having the highest effective refractive index on a sectional surface of the second waveguide portion is higher than an effective refractive index of the TE mode having the highest effective refractive index, and heights of waveguide structures (for example, cores) of the first waveguide portion and the second waveguide portion are equal to each other.

Journal ArticleDOI
TL;DR: A breakthrough in pulse energy from a monolithic fiber chirped pulse amplification system using higher-order mode propagation generating 300 µJ pulses with duration <500 fs (FWHM) and peak power >600 MW at 1.55 µm is shown.
Abstract: Energy scaling of femtosecond fiber lasers has been constrained by nonlinear impairments and optical fiber damage. Reducing the optical irradiance inside the fiber by increasing mode size lowers these effects. Using an erbium-doped higher-order mode fiber with 6000 µm2 effective area and output fundamental mode re-conversion, we show a breakthrough in pulse energy from a monolithic fiber chirped pulse amplification system using higher-order mode propagation generating 300 µJ pulses with duration 600 MW at 1.55 µm. The erbium-doped HOM fiber has both a record large effective mode area and excellent mode stability, even when coiled to reasonable diameter. This demonstration proves efficacy of a new path for high energy monolithic fiber-optic femtosecond laser systems.

Journal ArticleDOI
TL;DR: In this paper, the effect of 1 μm thick silver iodide (AgI) coatings on the fundamental modes in cylindrical waveguides at terahertz (THz) frequencies, in the regime of the dielectric layer being thinner than the optimal thickness hopt� 2 THz� ≈ 20 μm.
Abstract: Thin dielectric layers inside hollow metallic waveguides are used to improve the waveguide transmission characteristics as the dominant waveguide mode changes into the hybrid HE11 mode. We investigate the effect of 1 μm thick silver iodide (AgI) coatings on the fundamental modes in cylindrical waveguides at terahertz (THz) frequencies, in the regime of the dielectric layer being thinner than the optimal thickness hopt� 2 THz� ≈ 20 μm. In the region of 1–3.2 THz, the lowest-order modes are similar in profile to the TE11 and TM11 modes, as determined by the timeresolved near-field measurements and verified numerically. Higher-order modes are detected experimentally as mode mixtures due to the multimode propagation. Numerical electromagnetic modeling is applied to resolve the mode structure ambiguity, allowing us to correlate experimentally detected patterns with a superposition of the TM11 and the higher-order mode, TE12. Mode profiles determined here indicate that in the regime of ultrathin dielectric (h ≪ 0.1λeff), the dielectric layer does not transform the dominant mode into the low-loss HE11 mode. Experimental mode patterns similar to the HE11 and the TE01 modes nevertheless can be formed due to mode beating. The results indicate that the Ag/AgI waveguides can be used for guiding THz waves in the TE01 mode or the TE12 mode with high discrimination against other modes. © 2012 Optical Society of America OCIS codes: 110.6795, 180.4243, 320.7100.

Journal ArticleDOI
TL;DR: A novel technique for the electronically-controllable generation and switching of transverse modes within a multi-mode fiber laser oscillator is presented and preliminary results demonstrate individual transverse mode lasing and fast switching between modes with watt-level output powers.
Abstract: A novel technique for the electronically-controllable generation and switching of transverse modes within a multi-mode fiber laser oscillator is presented. Preliminary results demonstrate individual transverse mode lasing and fast switching between modes with watt-level output powers. When applied to a core-pumped Tm-doped silica fiber laser with a multimode core the fundamental mode (LP01), the next higher order mode (LP11), or a donut-shaped LP11 superposition were selectively excited with power levels in excess of 5 W. Fast switching between LP01 and LP11 modes at up to 20kHz was also realized.

Patent
20 Sep 2013
TL;DR: In this paper, a photonic lantern spatial multiplexer that provides mode selectivity includes a multimode optical waveguide and a plurality of single-mode optical waveguides.
Abstract: A photonic lantern spatial multiplexer that provides mode selectivity includes a multimode optical waveguide and a plurality of single mode optical waveguides. The single mode cores of the single mode optical waveguides merge with the multimode core of the multimode optical waveguide. At least two of the single mode cores have different respective single mode effective refractive indexes.