Doubleclad fibers enable lasers to handle high power laser. The ytterbiumdoped rod is typically used in output stages of amplifier chains for pulsed laser amplification. The scars may avoid the core, then the mode is not coupled, and it is vain to excite such a mode in the double clad fiber amplifier. Thermal modeling, heat mitigation, and radiative cooling. Absorption efficiency of doubleclad fiber based on zemax. Simulation and design of a multistage 10w thuliumdoped double. Liekki yb12004125 is a highly doped ytterbium fiber for low noise, low nonlinearity preamplifiers and lasers. Rp photonics encyclopedia doubleclad fibers, cladding. High power erbiumdoped fiber amplifier eydfahp is based on the double clad erbiumdoped fiber amplification technology, a unique optical packaging process is adopted and a reliable hardware optical path protection design is adopted to realize the highpower laser output of cband or lband. Tervonensoftware tools for integrated optics design. Download citation absorption efficiency of doubleclad fiber based on zemax in order to calculate the absorption efficiency of different double clad.
Steady state simulation with raman scattering class steadystatesimulationwithraman steadystatesimulationwithraman is the main class for running giles model simulations with raman scattering. Consequently new analytical formulas for the raman threshold are obtained and their accuracy is tested. Simulation and experiment of erbiumytterbium codoped. Oct 23, 2019 pyfiberamp is a rate equation simulation library for rareearthdoped fiber amplifiers and fiber lasers partly based on the giles model. Claddingpumped fiber amplifier based on a double clad fiber with freespace coupling. Evolution of optical powers in an ytterbiumdoped double clad fiber amplifier. Introduction ytterbium ybdoped fiber lasers and amplifiers have become an attractive option for generating light in the 1. Atomic rate equations in double clad fiber laser by considering a threelevel laser system with a fast decay of third level and a steadystate regime that the populations are timeinvariant, the variations of the ground and upper levels are given as 30. To analyze the dynamic characteristics of the highpower ytterbiumdoped double clad fiber amplifier considering pulses in repetition rates of khz, a dynamic ytterbiumdoped fiber model is necessary. All fiber passive switching has been achieved by splicing yb double clad fiber to a piece of sm doped fiber 30. Doubleclad ybdoped fiber laser and its external cavity. Only with doubleclad fibers, very high output powers of fiber based amplifiers and lasers are possible. Singlemode operation of a coiled multimode fiber amplifier.
Passive dual clad fiber smm900 is a passive, dualcladding, multimode mm fiber that combines both singlemode sm and multimode fiber characteristics within a single fiber. Us6275250b1 fiber gain medium marking system pumped or. Fiber amplifiers based on ytterbiumor neodymiumdoped double clad fibers can be used to boost the output power of 1. Dynamic characteristics of doubleclad fiber amplifiers for highpower pulse amplification abstract. In some cases, average output powers have reached 55 w at around 1110 nm and have been limited primarily by the available pump power injected into the double clad fiber.
Osa efficiency of pump absorption in doubleclad fiber. On the theoretical side, a numerical model of nanosecond highpower ybdoped double clad pulse amplifiers has also been reported and used to analyze a range of nanosecond fiber amplifier. A complete theoretical study of doubleclad fiber amplifiers is proposed. Feb 08, 2012 double clad fibers are usually designed for fiber lasers and fiber amplifiers. Erbiumytterbium codoped double clad fiber amplifier, its. Figure 2 shows the crosssection of a double clad optical fiber for cladding pumping one of the products of ofs fitel that features this amplifier. The output of the fiber amplifer is then doubled in a ppln crystal and redoubled in a bbo. Packaged in a module, it is ideal for building ultrafast fiber lasers.
Being continuously tunable from 1260 to 40 nm, wltfflo is ideal for automated testing of the 100gbaselr4, 400gbaselr8, and 100gbasecwdm4 devices. Double clad fiber gain medium systems particularly adapted for marking indicia on surfaces of articles are disclosed. The class defines the fiber, boundary conditions and optical channels used in the simulation. Double clad eryb doped fiber for high power amplifiers for catv applications.
Other applications include catv pumpsignal couplers and light deliverycollection in fluorescence imaging. The increasing customer interest in fiber lasers and amplifiers operating at eye safe wavelengths has encouraged us to introduce the first in a new generation of highly efficient tmdoped double clad fibers where the silica glass composition has been carefully optimized for efficient operation at the important 2 mm wavelength range, says. The proposed 125 spl mum first cladding diameter in the double clad fiber, provides the singlemode propagation of the signal lightwave into its doped core without misguiding the signal lightwave. Its silica cladding where the launched pumping light of multimode. The amplifier is built in a two stage configuration with high power diode lasers at 980nm pumping each stage. We investigate diode pump absorption and temperature distribution in three erbiumdoped double clad fluoride fibers. The system worked at the repetition rate from 10 khz to 40 khz. We are trying to coupling light from a multimode fiber core diameter of 100200 um to a normal single mode fiber 9125 um. The dc20085ybrod is made by crystal fibre patented airclad technology and features low photodarkening. Using this broadband source to pump cascaded double clad passive fiber tapers, a 14.
Ase spectra for an ytterbiumdoped double clad fiber amplifier. Doubleclad fiber sources have become increasingly popular because of the high output beam quality. Sma905 doubleclad high power fiber cables for welding machine. Our ytterbium doped double clad fibers offers the largest singlemode cores in the world enabling amplification to unprecedented power levels while keeping. Figure 1 shows the system designed for this simulation. Osa singlemode operation of a coiled multimode fiber amplifier. Due to their unique design ytterbium sensitized erbium doped, double clad fiber amplifiers. Peak power up to 700w at 1545nm for 730ns pulse duration has been obtained with a good beam quality and a 17db per was measured. These ybdoped double clad fibers are ideal for medium and highpower applications up to 20 w including fiber power amplifiers. Secondgeneration nuamp polarizationmaintaining fiber amplifiers have been introduced by nufern. The fiber has a germanosilicate singlemode core, a pure silica inner cladding to guide the pump light. Supercontinuum generation in an ytterbiumdoped fiber.
Nkt photonics has introduced a new version of its crystal fiibre series doubleclad rodtype fiber. The most common example is the erbium doped fiber amplifier. Claddingpumped fibers are double clad, meaning that the fiber s coating acts as a second cladding, allowing the first cladding to function as a waveguide. Regarding the simulation of the single clad scf amplifier that we use as our preamplifier, extensive studies can be found in several publications. Double clad fibers have found extensive applications in high power fiber lasers and fiber amplifiers. A fiber laser or amplifier based on an ordinary doped singlemode fiber can generate a diffractionlimited output, but it restricts the pump sources to those with diffractionlimited beam quality and thus normally to those with low power. Double clad ytterbium fibers made with photonic crystal fiber technology are known as air clad fibers and provide a range of new benefits. Packaged in an aerogain gain module, the high performance of our fibers is easily accessible for building picosecond or femtosecond ultrafast fiber lasers. This fiber is ideal for use as a preamplifier in a fiber amplifier chain with double cladding fiber acting as a power amplifier. A lens system was used but coupling loss is still very significant. Theoretical modeling of wattlevel average power tmdoped fluoride glass fiber amplifiers operating at 1. It takes advantage of envelope pump technology, which overcomes shortcomings of the singlemode fiber, and makes output power increased one to two orders of magnitude, and promotes the evelopment of highpower fiber amplifier. Paired with glass or plastic fibers to measure in harsh environments. Absorption is measured via fluorescence intensity and temperature distribution is measured with thermal imaging.
High power 1550 nm amplifiers based on double clad eryb fibers are widely used in catv and telecom applications. Doublecladfiber extends activefiber and describes a double clad active fiber with singlemode stepindex core. Characterization of a highpower erbiumdoped fiber laser. The ase maximum has shifted to longer wavelengths, because the ytterbium excitation is now lower. Modeling and optimization of doubleclad fiber amplifiers. Regarding the simulation of the single clad scf amplifier that we use as our pre amplifier, extensive studies can be found in several publications. The pump light is launched into an inner cladding rather than into the much smaller fiber core, in which the laser light is generated. Powered by proprietary double clad fibers, the devices are housed in a compact package.
The main reason for that is that ase comes up at somewhat longer wavelengths. The right side picture shows the refractive indices of the three layers. Research and development around ybdoped double clad fiber has focused primarily on obtaining higher averageoutput power, in addition to high pulse energies and peak powers. Our ytterbium doped double clad fibers offer the largest singlemode cores in the world enabling amplification to unprecedented power levels while keeping mode quality and stability. Experimental demonstration and numerical simulation techniques have been used to systematically study the applications of such an amplifier and the effects of. Fiberlabs inc amplifiers, fiber outputlight sources. Theoretical study of the thermal distribution in ybdoped. Standard and custom fibers are available in various configurations passive single clad. They have demonstrated this method by constructing a coiled amplifier using ybdoped, double clad fiber with a core diameter of 25 microm and na of minus0. At the same time, the pump absorption in doubleclad fiber is under some.
A 7core erbium doped double clad fiber amplifier with sidecoupled pumping kazi s. The active fiber used is the single clad doped fiber from ofs, tmdf200. Using these new formulas, the dependence of the raman threshold on various parameters is studied. The geometry of the inner clad has an octagonal shape which allows a high coupling efficiency of the multimode pump wave into the fiber. Is there a free software for modelling systems that include. The influence of various design and fiber parameters on the. The extremely high numerical aperture na for the pump coreinner cladding is possible, allowing efficient pumping with inexpensivehigh power broad area emitting pumps. Rp photonics encyclopedia tutorial fiber amplifiers. When operated as an ase source, the output beam had an msup 2 value of 1. Rp fiber power simulation and design software for fiber optics, amplifiers and fiber lasers. Over 3 w singlefrequency laser output power was obtained with gain fibers shorter than 10 cm. With over 30 years experience of the specialty optical fiber industry, fibercore ltd, the world leader in its field, is exclusively dedicated to the design, manufacture and commercialization of specialty fibers.
Flattop pump distribution in the pump cladding is assumed as well as constant overlap between the pump modes and the core. We propose and demonstrate a double clad neodymium nddoped fiber amplifier ivdfa at 1. Based on the chaotic dynamics of rays in such fibers, we propose a quantitative theory for the pumpabsorption ratio and favorably compare the predictions of the theory with numerical results obtained. Highpower amplification ytterbiumdoped fibers with stable mode quality. Our ytterbium doped double clad fibers offers the largest singlemode cores in the world enabling amplification to unprecedented power levels while keeping mode quality and stability. The scars can be distributed more or less uniformly in socalled chaotic fibers 9 have more complicated crosssectional shape and provide more uniform distribution of intensity in the inner cladding, allowing. These systems provide a modulated output from a pump or seed semiconductor laser source to a double clad fiber gain medium which provides an amplified marking output scanned over the article surface with an optical scanner forming a plurality of strokes, the completion of which. Doped fiber amplifiers dfas are optical amplifiers that use a doped optical fiber as a gain medium to amplify an optical signal. New products claddingpumped optical fiber amplifier. When ixfiber was created in 2006, most of the team had some experience with erbiumytterbium codoped. The signal to be amplified and a pump laser are multiplexed into the doped fiber, and the signal is amplified through interaction with the doping ions. Customized fttx pon high power 1550nm eydfa, 8 ports based on multimode pumping eryb double clad fiber technology, eydfa is designed to produce high output power up to 23 dbm. In this case, a sequence of 5 gaussian pulses with a repetition rate of 100 khz was used. Photo 1 shows the appearance of a claddingpumped optical fiber amplifier for catv.
Polarization maintaining double clad eryb doped fiber. To set the ytterbiumdoped fiber component to work as double clad, the parameter double clad fiber enhanced tab has to be set to true and the value of the pump reference has to be specified. Numerical modeling of tmdoped doubleclad fluoride fiber. Absorption of an incoherent pump in a double clad fiber amplifier is analyzed in the paraxial wave approximation. The doubleclad fiber exhibits singlemode propagation for the laser output, while the pump radiation propagates in the multimode pump cladding. Modeling and optimization of doubleclad fiber amplifiers using. Pump absorption, laser amplification, and effective length in double. Double cladding fiber lasers dcfl are high power devices, involving a piece of non circular multimode structure, supporting a multimode pumping scheme. Highprecision sma905 fiber optic connector or modified sma905 metal connector with air gap protection at the end, equipped with largecore energy fiber with end face fine grinding, laser transmission power up to 600w. A pulsed master oscillator fiber power amplifier working in nanosecond range has been developed. Optical fibers come in double and tripleclad versions. To characterize and optimize these devices a computer model has been developed taking into account the full spectral information of the. The main attractions of such fiberbased power amplifiers. The fiber features a 65 m modefielddiameter ytterbium core.
We demonstrated this method by constructing a coiled amplifier using ybdoped, doubleclad fiber with a core diameter of 25 m and a numerical aperture of. Pump and signal combiner for bidirectional pumping of all fiber lasers and amplifiers. The erbiumdoped fiber amplifier edfa is the most deployed fiber amplifier as its amplification window coincides with the third transmission window of silicabased optical fiber. Fibercore offers a ytterbium doped, core pump fiber, df1100 for a 1060nm pre amplifier and a full range of erbium doped fibers in the isogain range, but specifically i15980125hc offers a. Sma905 double clad high power fiber cables for welding machine. Start features model fiber data versions interface demos. Simulation and experiment of erbiumytterbium codoped double. Depending on the fiber laser architecture, pre amplifiers are often used to reduce the gain level required from the power amplifier in a mopa system.
We show that the classic raman threshold formula is unsuitable to accurately predict the onset of raman scattering in highpower cw doubleclad fiber amplifiers. It is well known that the absorption of pump light injected into the pump cladding can be reduced by the effect that some of the modes of the pump cladding have a weak overlap with the doped fiber. Double clad fibers with a doped singlemode core and a noncylindrical multimode chaotic cladding are shown to provide optimal pumppower absorption in power amplifiers. The term master oscillator fiber amplifier mofa, mopfa, or fiber mopa is a variation of the term master oscillator power amplifier mopa, meaning a system where the power amplifier is a fiber amplifier. Hong po, dynamic characteristics of doubleclad fiber amplifiers for highpower pulse amplification. With product ranges available offering polarization maintaining, bendinsensitive, rareearth doped, claddingpump and photosensitive fibers. Numerical modeling of tmdoped doubleclad fluoride fiber amplifiers abstract. China 1550nm catv erbium doped fiber amplifier catv edfa. It is a single clad fiber for corepumped applications. Doubleclad fiber is used in thorlabs doubleclad fiber couplers, where the core carries a singlemode signal and the 1 st cladding is used to efficiently transfer a multimode signal to the coupled multimode fiber. We consider a doubleclad fiber as used for highpower fiber lasers and amplifiers. Rugged ip67 amplifier with output timing logic can be paired with glass or plastic fiber optics. High power erbiumdoped fiber amplifier dk photonics. The latter is usually a claddingpumped highpower amplifier, often based on an ytterbiumdoped fiber.
Rp photonics encyclopedia tutorial fiber amplifiers, part. Simple continuouswave, gainswitched and qswitched fiber lasers. Highpower fiber lasers and amplifiers rp photonics. Based on numerical modeling, the dynamic characteristics of highpower ytterbiumdoped double clad fiber amplifiers during the amplification of nanosecond pulses with kilohertz repetition rates are comprehensively analyzed. The notion of chaotic propagation is taken into account in order to improve the pumping process. Double clad fibers typically have a lowna single mode sm or largemodearea lma core for the emitted light and a highna, multimode first cladding for the pump light. Dynamic characteristics of doubleclad fiber amplifiers. A 7core erbium doped doubleclad fiber amplifier with. Photodarkening measurements in largemodearea fibers.
Two bands have developed in the third transmission window the conventional, or cband, from approximately 1525 nm 1565 nm, and the long, or lband, from. Amp fl56xx series oband fiber amplifiers are ideal for amplification of 100gbaselr4 wavelengths. Featuring integrated diode drivers and an output power monitor, they offer 1 or 50mw input and optional estop and usb control. Highpower fiber lasers and fiber amplifiers are nearly always realized with rareearthdoped double clad fibers, which are pumped with fiber coupled highpower diode bars or other kinds of laser diodes. Pump and signal combiner for bidirectional pumping of all. Double clad fiber amplifiers have also been demonstrated in the laboratory as highpower, highspeed transmitters. The core is dshaped for more efficient pump absorption. Kliner, a new method for side pumping of double clad fiber sources. Pump absorption and temperature distribution in erbiumdoped. The fiber amplifier consists of ytterbium doped double clad fiber cooled to low temperatures and incorperates a diode laser as the seed source. With product ranges available offering polarization maintaining, bendinsensitive, rareearth doped, claddingpump and. Some dispersion compensating fibers also use double clad. Ytterbiumdoped fibers, doubleclad fibers, fiber amplifiers, fiber lasers.
A master oscillator power amplifier mopa structured double clad ybdoped pulse fiber laser was presented, center wavelength of 1064nm, pulse width adjustable between 53ns147ns, repetition rate adjustable between 50khz200khz. In this thesis we investigate, a onestage, high power erbium and ytterbium codoped double clad fiber amplifier dcfa with output power of 1. An ytterbiumdoped double clad large mode area optical fiber was used as an amplifying medium. The 1550 nm passive double clad fiber is ideal for use both as a pump and signal output fiber in combiners and as a laser delivery fiber. Improved doubleclad fibers are based on crystal fibre. Optimized absorption in a chaotic doubleclad fiber amplifier. Doubleclad fibers enable lasers to handle high power. Improved doubleclad fibers are based on crystal fibre technology. The software takes in account the amplified spontaneous. We report a new approach to obtaining singletransversemode operation of a multimode fiber amplifier in which the gain fiber is coiled to induce significant bend loss for all but the lowestorder mode. Eryb erbium ytterbium double clad doped fibers, eryb fiber.
And this line of fiber amplifiers has been optimized for superior output power stability and the exceptionally low noise figures demanded by catv applications. Rp photonics encyclopedia fiber amplifiers, edfa, ydfa. The system used to simulate the double clad fiber amplifier counterpumped is shown in figure 5. Nkt photonics has introduced a new version of its crystal fiibre series double clad rodtype fiber. We report on singlefrequency all fiber amplifiers based on pm eryb doped p 2 o 5al 2 o 3sio 2 fibers. Steady state simulation with raman scattering pyfiberamp 0. In addition, a spacetime algorithm is used to optimize the distribution of rareearth dopant in the doubleclad fiber. Pulsed ytterbiumdoped large mode area doubleclad fiber. Raytracing calculations of absorption and heatequation modeling of temperature distribution are also conducted.
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