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ABSTRACT: We demonstrate the first erbium-doped fiber amplifier operating in a single, large-mode area, higher-order mode. A high-power, fundamental-mode, Raman fiber laser operating at 1480 nm was used as a pump source. Using a UV-written, long-period grating, both pump and 1564 nm signal were converted to the LP(0,10) mode, which had an effective area of 2700 microm(2) at 1550 nm. A maximum output power of 5.8 W at 1564 nm with more than 20 dB of gain in a 2.68 m long amplifier was obtained. The mode profile was undistorted at the highest output power.
Optics Express 08/2010; 18(17):17651-7. · 3.59 Impact Factor
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ABSTRACT: Multiple higher-order-modes propagating simultaneously in large-mode-area optical fibers are measured and their relative power levels quantified using spatially and spectrally resolved imaging.
Lasers and Electro-Optics (CLEO) and Quantum Electronics and Laser Science Conference (QELS), 2010 Conference on; 06/2010
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ABSTRACT: It is demonstrated that the lateral resolution of a non-linear scanning multi-photon microscope can be improved significantly by using the light from an LP<sub>02</sub> mode instead of a Gaussian-like beam.
Lasers and Electro-Optics (CLEO) and Quantum Electronics and Laser Science Conference (QELS), 2010 Conference on; 06/2010
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ABSTRACT: We demonstrate tuning of the output spectrum of an HOM fiber module by changing the dispersion curve. Spectral feature wavelengths can be changed systematically by changing the location of the zero-dispersion wavelength.
Lasers and Electro-Optics, 2009 and 2009 Conference on Quantum electronics and Laser Science Conference. CLEO/QELS 2009. Conference on; 07/2009
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C. Headley,
S. Ramachandran,
J. Phillips,
K. Brar, S. Ghalmi,
M.F. Yan,
J.W. Nicholson,
P.W. Wisk,
D. Trevor,
J. Fleming,
E. Monberg,
F. Dimarcello,
R.S. Windeler,
J.M. Fini,
D.J. DiGiovanni
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ABSTRACT: Fiber devices that amplify light propagating in a single fundamental mode face several challenges in extracting ever-increasing powers. Here we explore the advantages and present results showing amplification of light in a single higher order mode.
IEEE Lasers and Electro-Optics Society, 2008. LEOS 2008. 21st Annual Meeting of the; 12/2008
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Laser & Photonics Review 09/2008; 2(6):429 - 448. · 7.39 Impact Factor
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ABSTRACT: A new measurement technique, capable of quantifying the number and type of modes propagating in large-mode-area fibers is both proposed and demonstrated. The measurement is based on both spatially and spectrally resolving the image of the output of the fiber under test. The measurement provides high quality images of the modes that can be used to identify the mode order, while at the same time returning the power levels of the higher-order modes relative to the fundamental mode. Alternatively the data can be used to provide statistics on the level of beam pointing instability and mode shape changes due to random uncontrolled fluctuations of the phases between the coherent modes propagating in the fiber. An added advantage of the measurement is that is requires no prior detailed knowledge of the fiber properties in order to identify the modes and quantify their relative power levels. Because of the coherent nature of the measurement, it is far more sensitive to changes in beam properties due to the mode content in the beam than is the more traditional M(2) measurement for characterizing beam quality. We refer to the measurement as Spatially and Spectrally resolved imaging of mode content in fibers, or more simply as S(2) imaging.
Optics Express 06/2008; 16(10):7233-43. · 3.59 Impact Factor
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ABSTRACT: The stimulated Brillouin scattering (SBS) gain efficiencies were measured in the LP(08) and LP(01) modes of a higher-order-mode optical fiber. Gain efficiencies C(B) of 0.0085 and 0.20 (m-W)(-1) were measured for the LP(08) and LP(01) modes at 1083 nm, respectively. C(B) is inversely proportional to the optical effective area Aeff and the same core-localized acoustic phonon seeds the SBS process in each case. An acoustic modal analysis and a distributed phenomenological model are presented to facilitate the data analysis and interpretation. The LP(08) mode exhibits a threshold powerlength product of 2.5 kW-m.
Optics Express 12/2007; 15(24):15952-63. · 3.59 Impact Factor
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ABSTRACT: An SBS gain efficiency of 0.0088 (m-W)<sup>-1</sup> was measured in an LP<sub>08</sub> higher order mode optical fiber at 1083 nm. Comparative measurements in a single mode fiber confirm that the SBS threshold scales with the inverse modal effective area of 1714 mum<sup>2</sup> yielding a single frequency SBS threshold power-length product of 2.4 kW-m.
Lasers and Electro-Optics, 2007. CLEO 2007. Conference on; 06/2007
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ABSTRACT: Modelocking in an Yb-doped figure-eight fiber laser is demonstrated utilizing anomalous dispersion from an LP(02) higher-order-mode fiber for dispersion management. Outside the laser cavity, the pulses were re-compressed to 95 fs using a second HOM module, the shortest demonstrated pulses to date from an Yb-doped figure-eight fiber laser. Operation of the laser with HOM fiber in the cavity is compared to an Yb figure-eight laser that utilizes all-normal dispersion fibers.
Optics Express 06/2007; 15(11):6623-8. · 3.59 Impact Factor
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ABSTRACT: We demonstrate propagation of 14 nJ femtosecond pulses through a large-mode-area, higher-order-mode (HOM) fiber with an effective area of 2100 microm2. The pulses propagate stably in the LP07 mode of the fiber through lengths as long as 12 m. The strongly chirped pulses exiting the amplifier fiber are dechirped by the high-order-mode fiber, resulting in pulses with a peak power of 61 kW after propagation in 5 m of the positive-dispersion fiber. A small amount of self-phase modulation is observed in the compressed pulses and is described well by a nonlinear Schrödinger equation model that takes into account the measured effective area and dispersion of the HOM fiber.
Optics Letters 12/2006; 31(21):3191-3. · 3.40 Impact Factor
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ABSTRACT: We demonstrate soliton self-frequency shift below 1300 nm in a higher-order-mode optical fiber. This new class of fiber shows great promise of supporting frequency-shifted solitons in intermediate energy regimes unattainable using current fibers.
Lasers and Electro-Optics Society, 2006. LEOS 2006. 19th Annual Meeting of the IEEE; 11/2006
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ABSTRACT: We demonstrate an all-solid (nonholey), silica-based fiber with anomalous dispersion at wavelengths where silica material dispersion is negative. This is achieved by exploiting the enhanced dispersion engineering capabilities of higher-order modes in a fiber, yielding + 60 ps/nm km dispersion at 1080 nm. By coupling to the desired higher-order mode with low-loss in-fiber gratings, we realize a 5 m long fiber module with a 300 fs/nm dispersion that yields a 1 dB bandwidth of 51 nm with an insertion loss of approximately 0.1 dB at the center wavelength of 1080 nm. We demonstrate its functionality as a critical enabler for an all-fiber, Yb-based, mode-locked femtosecond ring laser.
Optics Letters 10/2006; 31(17):2532-4. · 3.40 Impact Factor
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ABSTRACT: We demonstrate robust single-transverse-mode light propagation in higher-order modes of a fiber, with effective area A(eff) ranging from 2,100 to 3,200 microm(2). These modes are accessed using long-period fiber gratings that enable higher-order-mode excitation over a bandwidth of 94 mm with greater than 99% of the light in the desired mode. The fiber is designed such that the effective index separation between modes is always large, hence minimizing in-fiber mode mixing and enabling light propagation over lengths as large as 12 m, with bends down to 4.5 cm radii. The modal stability increases with mode order, suggesting that A(eff) of this platform is substantially scalable.
Optics Letters 07/2006; 31(12):1797-9. · 3.40 Impact Factor
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ABSTRACT: We demonstrate propagation and compression of 14-nJ, 152-fs pulses in the 2100-mum<sup>2</sup> effective area, LP<sub>07</sub> mode of an intentionally multi-moded fiber. The 12-m length of fiber was coiled to a radius of curvature of 7.5 cm.
Lasers and Electro-Optics, 2006 and 2006 Quantum Electronics and Laser Science Conference. CLEO/QELS 2006. Conference on; 06/2006
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ABSTRACT: We demonstrate a higher-order-mode fiber-based platform, to achieve low-loss, bend-resistant, mode-coupling-free light transmission over meter-length fibers, in a record A<sub>eff</sub> of 2100 mum<sup>2</sup>. Its nonlinearity tolerance is demonstrated by compressing fiber-laser pulses to 64 fs, yielding 52-kW peak powers
Optical Fiber Communication Conference, 2006 and the 2006 National Fiber Optic Engineers Conference. OFC 2006; 04/2006
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ABSTRACT: We demonstrate the first all-solid (non-holey), silica-based fiber with anomalous-dispersion (+60ps/nm-km) at wavelengths (1080nm) where silica material dispersion is negative. We demonstrate its functionality as a critical enabler for an all-fiber, Yb-based, femtosecond ring laser.
Optical Fiber Communication Conference, 2006 and the 2006 National Fiber Optic Engineers Conference. OFC 2006; 04/2006
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ABSTRACT: Delivery of high peak-power femtosecond pulses with fibers is constrained by nonlinear distortions accumulated during pulse propagation. We address this problem with a novel, to our knowledge, fiber schematic, where the pulse propagates in a small Aeff (18 microm2) but highly dispersive (record value of approximately -900 ps/nm km) medium, enabled by transmission in the LP02 mode of a few-mode fiber. The novel fiber yields a low dispersion-to-nonlinear-length ratio (due to its large dispersion) despite its small Aeff, hence enabling mitigation of nonlinearities. This enables fiber delivery of distortion-free <150 fs, approximately 1 nJ, and 840 nm pulses--an order-of-magnitude improvement over single-mode fibers of similar Aeff.
Optics Letters 12/2005; 30(23):3225-7. · 3.40 Impact Factor
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ABSTRACT: Polarization dependence in microbend gratings is an inherent problem, even in perfectly circular fibers, since antisymmetric modes are almost degenerate linear combinations of four distinct, polarization-sensitive modes. We demonstrate a novel fiber design that lifts polarization degeneracies of the antisymmetric modes to solve this problem. By intentionally exacerbating the polarization splittings, we achieve coupling to only the polarization-insensitive doublet, over wavelength ranges exceeding 100 nm, thus demonstrating a device with practical usable bandwidths. This allows all previous applications envisaged with UV-induced long-period gratings to be realized with the significantly lower-cost microbend technology platform.
Optics Letters 12/2005; 30(21):2864-6. · 3.40 Impact Factor
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ABSTRACT: We utilize the highly dispersive nature of the LP<sub>02</sub> mode (dispersion∼ -900 ps/nm-km) to enable SPM-distortion free fs-pulse propagation in a small A<sub>eff</sub> fiber (18 μm<sup>2</sup>). This facilitates delivery of sub-150-fs, 1-nJ, 840-nm pulses - an order of magnitude improvement over SMF of similar A<sub>eff</sub>.
Optical Communication, 2005. ECOC 2005. 31st European Conference on; 10/2005
