Showing papers on "Photonic-crystal fiber published in 2006"
04 Oct 2006
TL;DR: In this paper, a review of numerical and experimental studies of supercontinuum generation in photonic crystal fiber is presented over the full range of experimentally reported parameters, from the femtosecond to the continuous-wave regime.
Abstract: A topical review of numerical and experimental studies of supercontinuum generation in photonic crystal fiber is presented over the full range of experimentally reported parameters, from the femtosecond to the continuous-wave regime. Results from numerical simulations are used to discuss the temporal and spectral characteristics of the supercontinuum, and to interpret the physics of the underlying spectral broadening processes. Particular attention is given to the case of supercontinuum generation seeded by femtosecond pulses in the anomalous group velocity dispersion regime of photonic crystal fiber, where the processes of soliton fission, stimulated Raman scattering, and dispersive wave generation are reviewed in detail. The corresponding intensity and phase stability properties of the supercontinuum spectra generated under different conditions are also discussed.
3,361 citations
TL;DR: The history, fabrication, theory, numerical modeling, optical properties, guidance mechanisms, and applications of photonic-crystal fibers are reviewed.
Abstract: The history, fabrication, theory, numerical modeling, optical properties, guidance mechanisms, and applications of photonic-crystal fibers are reviewed
1,488 citations
TL;DR: In this article, the authors proposed a Microstructured Optical Fiber-based Surface Plasmon Resonance sensor with optimized microfluidics, where plasmons on the inner surface of large metallized channels containing analyte can be excited by a single mode microstructured fiber.
Abstract: The concept of a Microstructured Optical Fiber-based Surface Plasmon Resonance sensor with optimized microfluidics is proposed. In such a sensor plasmons on the inner surface of large metallized channels containing analyte can be excited by a fundamental mode of a single mode microstructured fiber. Phase matching between plasmon and a core mode can be enforced by introducing air filled microstructure into the fiber core, thus allowing tuning of the modal refractive index and its matching with that of a plasmon. Integration of large size microfluidic channels for efficient analyte flow together with a single mode waveguide of designable effective refractive index is attractive for the development of integrated highly sensitive MOF-SPR sensors operating at any designable wavelength.
374 citations
TL;DR: The robust single-transverse-mode propagation in a passive 100 microm core fiber with a similar design reveals the potential of extended large-mode-area photonic crystal fibers.
Abstract: We report on an ytterbium-doped photonic crystal fiber with a core diameter of 60 μm and mode-field-area of ~2000 μm2 of the emitted fundamental mode. Together with the short absorption length of 0.5 m this fiber possesses a record low nonlinearity which makes this fiber predestinated for the amplification of short laser pulses to very high peak powers. In a first continuous-wave experiment a power of 320 W has been extracted corresponding to 550 W per meter. To our knowledge this represents the highest power per unit length ever reported for fiber lasers. Furthermore, the robust single-transverse-mode propagation in a passive 100 μm core fiber with a similar design reveals the potential of extended large-mode-area photonic crystal fibers.
358 citations
TL;DR: Experimental results showing that long-period gratings in photonic crystal fibers can be used as sensitive biochemical sensors and has a sensitivity of approximately 1.4nm/1nm in terms of the shift in resonance wavelength in nm per nm thickness of biomolecule layer.
Abstract: We present experimental results showing that long-period gratings in photonic crystal fibers can be used as sensitive biochemical sensors. A layer of biomolecules was immobilized on the sides of the holes of the photonic crystal fiber and by observing the shift in the resonant wavelength of a long-period grating it was possible to measure the thickness of the layer. The long-period gratings were inscribed in a large-mode area silica photonic crystal fiber with a CO2 laser. The thicknesses of a monolayer of poly-L-lysine and double-stranded DNA was measured using the device. We find that the grating has a sensitivity of approximately 1.4nm/1nm in terms of the shift in resonance wavelength in nm per nm thickness of biomolecule layer.
340 citations
TL;DR: The fabrication and characterization of a new type of hollow-core photonic crystal fiber based on large-pitch kagome lattice lattice cladding is reported, with broad optical transmission bands covering the visible and near-IR parts of the spectrum with relatively low loss and low chromatic dispersion.
Abstract: We report the fabrication and characterization of a new type of hollow-core photonic crystal fiber based on large-pitch (∼12μm) kagome lattice cladding. The optical characteristics of the 19-cell, 7-cell, and single-cell core defect fibers include broad optical transmission bands covering the visible and near-IR parts of the spectrum with relatively low loss and low chromatic dispersion, no detectable surface modes and high confinement of light in the core. Various applications of such a novel fiber are also discussed, including gas sensing, quantum optics, and high harmonic generation.
310 citations
TL;DR: This paper demonstrates experimentally that Brillouin slow light with an arbitrary large bandwidth can be readily obtained in conventional optical fibers using a simple and inexpensive pump spectral broadening technique and sees no limit to extend this technique to the delaying of GHz-bandwidth signals.
Abstract: Brillouin slow light in optical fibers is a promising technique for the development of all-optical buffers to be used in optical routers. The main drawback of this technique up to now has been its narrow bandwidth, normally restricted to 35 MHz in conventional single-mode optical fibers. In this paper we demonstrate experimentally that Brillouin slow light with an arbitrary large bandwidth can be readily obtained in conventional optical fibers using a simple and inexpensive pump spectral broadening technique. In our experiments, we show the delaying of 2.7 ns pulses over slightly more than one pulse length with only some residual broadening (<25%) of the pulse width. We see no limit to extend this technique to the delaying of GHz-bandwidth signals.
279 citations
TL;DR: The fabrication of photonic crystal fibers with a continuously-decreasing zero-dispersion wavelength along their length is reported, designed to extend the generation of supercontinuum spectra from the visible into the ultraviolet.
Abstract: We report the fabrication of photonic crystal fibers with a continuously-decreasing zero-dispersion wavelength along their length. These tapered fibers are designed to extend the generation of supercontinuum spectra from the visible into the ultraviolet. We report on their performance when pumped with both nanosecond and picosecond sources at 1.064 microm. The supercontinuum spectra have a spectral width (measured at the 10 dB points) extending from 0.372 microm to beyond 1.75 microm. In an optimal configuration a flat (3 dB) spectrum from 395 to 850 nm, with a minimum spectral power density of 2 mW/nm was achieved, with a total continuum output power of 3.5 W. We believe that the shortest wavelengths were generated by cascaded four-wave mixing: the continuous decrease of the zero dispersion wavelength along the fiber length enables the phase-matching condition to be satisfied for a wide range of wavelengths into the ultraviolet, while simultaneously increasing the nonlinear coefficient of the fiber.
255 citations
TL;DR: A new approach to evanescent field sensing is presented, in which both core and cladding are microstructured, in order to improve fibre sensing for low refractive index materials such as liquids and gases.
Abstract: The development of microstructured fibres offers the prospect of improved fibre sensing for low refractive index materials such as liquids and gases. A number of approaches are possible. Here we present a new approach to evanescent field sensing, in which both core and cladding are microstructured. The fibre was fabricated and tested, and simulations and experimental results are shown in the visible region to demonstrate the utility of this approach for sensing.
246 citations
TL;DR: In this article, the authors demonstrate robust single-transverse-mode light propagation in higher-order modes of a fiber, with effective area Aeff ranging from 2100 to 3200 μm2.
Abstract: We demonstrate robust single-transverse-mode light propagation in higher-order modes of a fiber, with effective area Aeff ranging from 2100 to 3200 μm2. 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 Aeff of this platform is substantially scalable.
234 citations
TL;DR: A long-period fiber-grating sensor with a high strain sensitivity and low temperature sensitivity is fabricated by use of focused CO(2) laser beam to carve periodic grooves on a large- mode-area photonic crystal fiber to reduce the cross-sensitivity between strain and temperature.
Abstract: A long-period fiber-grating sensor with a high strain sensitivity of −7.6 pm/μe and a low temperature sensitivity of 3.91 pm/°C is fabricated by use of focused CO2 laser beam to carve periodic grooves on a large- mode-area photonic crystal fiber. Such a strain sensor can effectively reduce the cross-sensitivity between strain and temperature, and the temperature-induced strain error obtained is only 0.5 μe/°C without using temperature compensation.
TL;DR: Simulations show that the parabolic-profile design has a natural immunity to bend-induced mode distortion and contraction, and shows superior performance in simulated fair comparisons with other fiber families, including microstructure fibers.
Abstract: Achieving very large mode area is a key goal in current research on microstructure and solid fibers for high power amplifiers and lasers. One particular design regime of recent interest has effective area over 1000 square microns and has effectively-single-mode operation ensured by bend losses of the higher-order modes. Simulations show that these fibers are extremely prone to bend-induced distortion and reduction in mode area. The calculated area reduction would significantly impact nonlinear impairments for bend radii relevant to any reasonable spooled package, and can be over 50 percent for bend radii tighter than 10cm. The parabolic-profile design has a natural immunity to bend-induced mode distortion and contraction, and shows superior performance in simulated fair comparisons with other fiber families, including microstructure fibers.
TL;DR: A fiber-based frequency comb system consisting of a simple mode-locked fiber laser and a backward pumping amplifier combined with a highly nonlinear fiber with a short zerodispersion wavelength is developed, and the signal to noise ratio of the obtained carrier-envelope-offset frequency beat is larger than 45 dB at a bandwidth of 100 kHz.
Abstract: We have developed a fiber-based frequency comb system consisting of a simple mode-locked fiber laser and a backward pumping amplifier combined with a highly nonlinear fiber with a short zerodispersion wavelength. As a result, the signal to noise ratio of the obtained carrier-envelope-offset frequency beat is larger than 45 dB at a bandwidth of 100 kHz. Furthermore, we have succeeded in measuring the optical frequencies of a 1542-nm acetylene-stabilized laser and a 532-nm iodinestabilized Nd:YAG laser continuously for more than one week using the fiber-based comb system. The long-term measurement revealed that the frequency stability of the iodine-stabilized laser was 5.7 x 10(-15) with 100 000 s averaging.
TL;DR: The development of microstructured optical fibers has led to the realization of many optical properties in fiber form that were not previously attainable as discussed by the authors, and some of the key applications of micro-structured fibers, including nonlinear fiber-based devices and fibers for high power light delivery, are reviewed.
Abstract: ▪ Abstract The development of microstructured optical fibers has led to the realization of many optical properties in fiber form that were not previously attainable. This chapter reviews the background to this work and overviews both the fundamentals of and progress in fabricating and modeling these structures. Until relatively recently, most of the work in this field was based on silica glass; this chapter provides an update on progress in developing microstructured fibers from other materials such as soft glasses. Some of the key applications of microstructured fibers, including nonlinear fiber–based devices and fibers for high power light delivery, are also reviewed.
TL;DR: In this paper, the performance of an Yb-doped, 100μm core rod-like photonic crystal fiber (PCF) used as the final amplifier in a gain-staged master-oscillator/power-amplifier source was reported.
Abstract: The authors report on the performance of an Yb-doped, 100μm core rodlike photonic crystal fiber (PCF) used as the final amplifier in a gain-staged master-oscillator/power-amplifier source. From the PCF, they obtained 1-ns-long pulses of energy in excess of 4.3mJ, peak/average power ∼4.5MW∕42W, and spectral linewidth ∼20GHz. The PCF emitted a beam exhibiting near-Gaussian, single-transverse-mode profile of M2∼1.3.
TL;DR: In this article, the inner walls of a photonic band-gap fiber are covered with organosilane and light-induced atomic desorption is used to release Rb atoms into the core.
Abstract: We show that rubidium vapor can be produced within the core of a photonic band-gap fiber yielding an optical depth in excess of 2000. Our technique for producing the vapor is based on coating the inner walls of the fiber core with organosilane and using light-induced atomic desorption to release Rb atoms into the core. As an initial demonstration of the potential of this system for supporting ultralow-level nonlinear optical interactions, we perform electromagnetically induced transparency with control-field powers in the nanowatt regime, which represents more than a 1000-fold reduction from the power required for bulk, focused geometries.
Book•
11 Sep 2006TL;DR: In this paper, the authors present a history of the use of light propagation in fiber propagation in a waveguide and the future use of a wave-guide in a fiber-waver.
Abstract: HISTORY OF POLYMER OPTICAL FIBERS Introduction Using Light for Telecommunications Glass Fibers Polymer Fibers The Future LIGHT PROPAGATION IN A FIBER WAVEGUIDE Introduction Bound Modes of Step-Index Fibers Multimode Waveguides Ray Propagation in a Graded-Index Medium Directional Couplers Conclusion Acknowledgments FABRICATING FIBERS Making Polymer Fibers by Extrusion Making Polymer Fiber by Drawing a Preform Birefringence of Drawn Fibers Mechanical Properties of Fibers THEORY OF REFRACTIVE INDEX AND LOSS Refractive Index Optical Loss Bending Loss Dispersion A Practical Example Polarization CHARACTERIZATION TECHNIQUES AND PROPERTIES Refractive Index Optical Loss Numerical Aperture Bandwidth TRANSMISSION, LIGHT SOURCES, AND AMPLIFIERS Transmission Displays Optical Amplification and Lasing OPTICAL SWITCHING Electrooptic Switching All-Optical Switching STRUCTURED FIBERS AND SPECIALTY APPLICATIONS Bragg Gratings Advanced Structured Fibers Photorefraction Stress and Temperature Sensors Chemical Sensors Appendix - Coupled Wave Equation SMART FIBERS AND MATERIALS Smart Materials Photomechanical Effects The Future of Smart Photonic Materials CONCLUSION Bibliography Index
TL;DR: A prototype of a nonlinear optical endoscope based on a double-clad photonic crystal fiber to improve the detection efficiency and a MEMS mirror to steer the light at the fiber tip is reported on.
Abstract: Two-photon fluorescence and second harmonic generation microscopy have enabled functional and morphological in vivo imaging. However, in vivo applications of those techniques to living animals are limited by bulk optics on a bench top. Fortunately, growing functionality of fiber-optic devices and miniaturization of scanning mirrors stimulate the race to develop nonlinear optical endoscopy. In this paper, we report on a prototype of a nonlinear optical endoscope based on a double-clad photonic crystal fiber to improve the detection efficiency and a MEMS mirror to steer the light at the fiber tip. The miniaturized fiber-optic nonlinear microscope is characterized by rat esophagus imaging. Line profiles from the rat tail tendon and esophagus prove the potential of the technology in in vivo applications.
TL;DR: The "Stack & Draw" procedure is demonstrated to be a powerful tool against crystallisation when used with a very stable chalcogenide glass, and the mode field diameter of the fundamental mode is measured and compared with calculations using the multipole method.
Abstract: We report recent progress on fabrication of solid core microstructured fibers in chalcogenide glass. Several complex and regular holey fibers from Ga5Ge20Sb10S65 chalcogenide glass have been realized. We demonstrate that the “Stack & Draw“ procedure is a powerful tool against crystallisation when used with a very stable chalcogenide glass. For a 3 ring multimode Holey Fiber, we measure the mode field diameter of the fundamental mode and compare it successfully with calculations using the multipole method. We also investigate, via numerical simulations, the behaviour of fundamental mode guiding losses of microstructured fibers as a function of the matrix refractive index, and quantify the advantage obtained by using a high refractive index glass such as chalcogenide instead of low index glass.
TL;DR: It is shown that hollow core microstructured polymer optical fibers can be used for sensing, whilst also fabricating a chiral optical fiber based on material chirality, which has many applications in its own right.
Abstract: Guidance in a liquid core is possible with microstructured optical fibers, opening up many possibilities for chemical and biochemical fiber-optic sensing. In this work we demonstrate how the bandgaps of a hollow core microstructured polymer optical fiber scale with the refractive index of liquid introduced into the holes of the microstructure. Such a fiber is then filled with an aqueous solution of (-)-fructose, and the resulting optical rotation measured. Hence, we show that hollow core microstructured polymer optical fibers can be used for sensing, whilst also fabricating a chiral optical fiber based on material chirality, which has many applications in its own right.
TL;DR: A wavelength-spacing tunable multiwavelength erbium-doped fiber laser based on degenerate four-wave mixing in a dispersion-shifted fiber incorporating multiple-fiber Bragg gratings is experimentally demonstrated.
Abstract: We experimentally demonstrate a wavelength-spacing tunable multiwavelength erbium-doped fiber laser based on degenerate four-wave mixing in a dispersion-shifted fiber incorporating multiple-fiber Bragg gratings. We have achieved stable operation of the multiwavelength erbium-doped fiber laser, which has 0.8 nm spacing ten-channel lasing wavelengths and a high extinction ratio of more than ∼45 dB, at room temperature. The output power of the multiwavelength erbium-doped fiber laser is stable, so the peak fluctuation is less than ∼0.2 dB. By changing the properties such as loss and polarization state of multiple fiber Bragg grating cavities, we can exercise flexible control of the wavelength spacing of the multiwavelength output. We can also obtain switchable multiwavelength lasing operation by elimination of the effects of alternate single-fiber Bragg gratings.
TL;DR: A hybrid photonic crystal fiber in which a guided mode is confined simultaneously by modified total internal reflection from an array of air holes and antiresonant reflection from a line of high-index inclusions is presented.
Abstract: We present a hybrid photonic crystal fiber in which a guided mode is confined simultaneously by modified total internal reflection from an array of air holes and antiresonant reflection from a line of high-index inclusions. Experimental results demonstrate that this fiber shares properties of both index-guided and photonic bandgap structures.
TL;DR: The results demonstrate that the liquid-core PCF is capable to generate dramatically broadened supercontinua in a range from 700 nm to more than 2500 nm when pumping at 1.55 mum with subpicosecond pulses.
Abstract: We have numerically studied a hollow-core photonic crystal fiber, with its core filled with highly nonlinear liquids such as carbon disulfide and nitrobenzene Calculations show that the fiber has an extremely high nonlinear parameter γ on the order of 24/W/m at 155 μm The group velocity dispersion of this fiber exhibits an anomalous region in the near-infrared, and its zero-dispersion wavelength is around 155 μm This leads to potentially significant improvements and a large bandwidth in supercontinuum generation The spectral properties of the supercontinuum generation in liquid-core photonic crystal fibers are simulated by solving the generalized nonlinear Schrodinger equation The results demonstrate that the liquid-core PCF is capable to generate dramatically broadened supercontinua in a range from 700 nm to more than 2500 nm when pumping at 155 μm with subpicosecond pulses
TL;DR: Active Q-switching of an all-fiber laser using a Bragg grating based acousto-optic modulator is reported using erbium-doped fiber and a maximum pump power of 180 mW.
Abstract: We report active Q-switching of an all-fiber laser using a Bragg grating based acousto-optic modulator. Q-switching is performed by modulating a fiber Bragg grating with an extensional acoustic wave. The acoustic wave modulates periodically the effective index profile of the FBG and changes its reflection features. This allows controlling the Q-factor of the cavity. Using 1 m of 300 ppm erbium-doped fiber and a maximum pump power of 180 mW, Q-switch pulses of 10 W of peak power and 82 ns wide were generated. The pulse repetition rate of the laser can be continuously varied from few Hz up to 62.5 kHz.
TL;DR: In this article, a thin metal layer is deposited on a single-mode tapered optical fiber and the layer takes a semi-cylindrical shape The fundamental fiber mode can excite the different hybrid surface plasmon modes supported by the semi cylindrical metallic shell, and the transmission spectrum of the device exhibits multiple resonance peaks with either TE- or TM-polarized light.
Abstract: When a thin metal layer is deposited on a single-mode tapered optical fiber the layer takes a semi-cylindrical shape The fundamental fiber mode can excite the different hybrid surface plasmon modes supported by the semi-cylindrical metallic shell As a consequence, the transmission spectrum of the device exhibits multiple resonance peaks with either TE- or TM-polarized light The positions of those peaks are remarkably shifted when the refractive index of the medium adjacent to the metal layer changes Experimentally, we have found that by monitoring the first three resonance peaks a refractive index resolution of about 7 × 10 −7 can be achieved Our devices can be used for high-resolution biosensing
TL;DR: In this article, a simple, compact, and low-cost optical fiber refractive index (RI) sensor is reported, which consists of a multimode fiber in which a short section of standard singlemode fiber (SMF) is inserted.
Abstract: A simple, compact, and low-cost optical fiber refractive-index (RI) sensor is reported. It consists of a multimode fiber in which a short section of standard single-mode fiber (SMF) is inserted. Owing to the core diameter mismatch, the cladding of the SMF guides light. This makes the device sensitive to the external RI. The maximum resolution of the sensor is about 7times10-5. The fabrication of the sensor only requires cleaving and fusion splicing; moreover, the device can operate at different wavelengths, which makes it attractive for diverse applications
Patent•
26 May 2006TL;DR: A simple technique to obtain stable room temperature multiwavelength lasing in an erbium-doped fiber laser by the inhomogeneous loss mechanism by incorporating a section of highly nonlinear fiber and a Fabry-Perot filter in the laser cavity is demonstrated.
Abstract: We demonstrated a simple technique to obtain stable room temperature multiwavelength lasing in an erbium-doped fiber laser by the inhomogeneous loss mechanism. Successful reduction of the cross-gain saturation in erbium-doped fiber was achieved by incorporating a section of highly nonlinear fiber (HNLF) and a Fabry-Perot filter (FPF) in the laser cavity. More than 70 wavelengths simultaneous lasing were observed with the same frequency space of 25GHz. The laser had a total output power of ~3.2dBm, a bandwidth of 0.012nm (~1.5GHz) and a signal-to-spontaneous-noise ratio of ~44dB. Furthermore, the total output power can be increased to more than 190mW by moving the output port right after the EDFA.
TL;DR: It is shown that the use of grating reshaped parabolic pulses allows substantially better performance in terms of the extent of SPM-based spectral broadening and flatness relative to conventional hyperbolic secant (sech) pulses.
Abstract: We propose a new method for generating flat self-phase modulation (SPM)-broadened spectra based on seeding a highly nonlinear fiber (HNLF) with chirp-free parabolic pulses generated using linear pulse shaping in a superstructured fiber Bragg grating (SSFBG). We show that the use of grating reshaped parabolic pulses allows substantially better performance in terms of the extent of SPM-based spectral broadening and flatness relative to conventional hyperbolic secant (sech) pulses. We demonstrate both numerically and experimentally the generation of SPM-broadened pulses centred at 1542 nm with 92% of the pulse energy remaining within the 29 nm 3 dB spectral bandwidth. Applications in spectra slicing and pulse compression are demonstrated.
TL;DR: In this article, a hollow core photonic crystal fiber (HCPCF) surface-enhanced Raman probe consisting of a HCPCF with Au nanoparticles coated on the inner surface of the air holes serving as the substrate of surface enhanced Raman scattering (SERS) is demonstrated.
Abstract: The authors demonstrate a hollow core photonic crystal fiber (HCPCF) surface-enhanced Raman probe consisting of a HCPCF with Au nanoparticles coated on the inner surface of the air holes serving as the substrate of surface-enhanced Raman scattering (SERS). The experimental results indicate that the confinement of light inside the HCPCF and the coating of nanoparticles/analyte inside the air holes of the HCPCF offer a large area for the light to interact with the SERS particles. An optimized design of the HCPCF is provided to further improve the probe sensitivity.