Erbium-ytterbium Co-doped Fiber Research Articles

Single-wavelength fiber laser with 250 mW output power at 157 µm

A novel single-wavelength fiber ring laser with 250 mW output power is reported. A double-clad polarization-maintaining erbium-ytterbium co-doped fiber was used in a unidirectional ring cavity as an active medium to eliminate spatial hole-burning effect in the cavity. The output of the laser was single-longitudinal mode. A fiber Fabry-Perot filter was used in the cavity to increase the longitudinal-mode spacing which eliminated the mode hopping. The maximum output power produced by the laser without mode hopping was 250 mW. The optical signal to noise ratio (OSNR) of the laser was more than 40 dB.

L-band tunable multiwavelength fiber laser using an unpumped polarization maintaining an erbium-ytterbium double-clad fiber-loop mirror

An L-band tunable multiwavelength source is newly proposed and demonstrated employing an unpumped polarization maintaining an erbium-ytterbium codoped double-clad fiber (PM-EYDF) loop mirror in a semiconductor optical amplifier-based fiber-ring laser. This is achieved by only adjusting the polarization controller in the loop mirror for the birefringence of the PM-EYDF, which is polarization dependent, and which originates from the fact that the traversing signal with a different polarization state absorbed by the PM-EYDF changes its effective birefringence. A similar behavior also happens when the traversing signal power is varied. The multiwavelength operation with the tunable range as large as the comb spacing of the transmission spectrum of the PM-EYDF loop mirror is successfully accomplished.

Extractable energy from erbium-ytterbium co-doped pulsed fiber amplifiers and lasers

An analytic model is developed for evaluating the extractable energy from high energy pulsed erbium-ytterbium co-doped fiber amplifiers and lasers. The energy extraction capabilities under the limitation of spurious lasing, due to amplified spontaneous emission (ASE), are mapped for various numerical apertures, single and multi transverse mode evolution and operating wavelengths. The model provides an assessment for the maximum pulse energy that can be extracted from a given erbium-ytterbium co-doped fiber. In addition, the model can be used to determine the repetition rate and optimal length, under which the laser source will be optimally operated in order to achieve a required extracted energy, without spurious lasing. The results show a clear advantage in using 915nm wavelength pump source over 975nm, at high average power operation, due to augmented 1μm ASE at 975nm pump wavelength, as a result of the Yb3+ population inversion.

L-band Superfluorescent Fiber Source

An L band superfluorescent fiber source (SFS) is presented. The spectrum covers wavelengths from 1560 nm to 1615 nm. The L band SFS is constructed by a low power L band amplified spontaneous emission (L-ASE) seed source and a high power erbium-ytterbium co-doped fiber (EYDF) amplifier in double pass configuration. The output power of 0.72 W is obtained under 5.0 W, 980 nm pump power.

Highly efficient in-band pumped Er:YAG laser with 60 W of output at 1645 nm

A high-power Er:YAG laser that is in-band pumped by a high-power cladding-pumped erbium-ytterbium codoped fiber laser operating at 1532 nm is reported. The Er:YAG laser produced 60.3 W of continuous-wave output at 1645.3 nm in a beam with M2 approximately equal to 3 for 82 W of incident pump power and 20 W of TEM00 output with M2 < 1.2 for 32.4 W of incident pump power. The slope efficiency with respect to incident pump power at pump powers of >20 W was approximately 81%. In the Q-switched mode of operation, a slightly modified resonator configuration incorporating an electro-optic Q switch produced pulses of approximately 4 mJ energy and approximately 100 ns (FWHM) duration, corresponding to a peak power of approximately 42 kW at a repetition rate of 1 kHz for an incident pump power of 16.8 W. The prospects for further improvement in continuous-wave and Q-switched performance are discussed.

All fiber erbium‐ytterbium co‐doped fiber laser

AbstractAn all‐fiber erbium‐ytterbium co‐doped fiber laser (EYDFL), with a double‐cladding erbium‐ytterbium co‐doped fiber (EYDF) of 15 m as active fiber, is reported. Up to 1.027‐W output power at 1567.0 nm under pump power of 3.16 W and slope efficiency of 34.5% with respect to the launched pump power are obtained. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 31–34, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21072

Experimentally verified modeling of erbium-ytterbium co-doped DFB fiber lasers

For the first time, the simulation results of fiber distributed feedback (DFB) lasers are compared against experimental data in this paper. The pump source, active medium, and grating are all modeled and simulated to predict actual laser characteristics. Simple characterization methods are illustrated for the measurement of model parameters. Large loss at the pump wavelength is observed, attributed to the lifetime quenching of Yb ions, and included in the model as a critical parameter. DFB lasers with two different apodization profiles successfully simulated with the same set of model parameters.

Watt-level L band superfluorescent fiber source

An L band superfluorescent fiber source (SFS) with output power of 0.94W is presented, under 4.4W 976nm pump power. The optical conversion efficiency is about 21%. The spectrum covers the broad wavelength range from 1560nm to 1615nm. The high power L band SFS is constructed by a low power L band amplified spontaneous emission (ASE) seed source and a high power erbium-ytterbium co-doped fiber (EYDF) amplifier in double pass forward pumping configuration.

Highly efficient Er,Yb-doped fiber laser with 188W free-running and &gt; 100W tunable output power

Efficient high-power operation of an erbium-ytterbium co-doped fiber laser cladding-pumped by two spatially-multiplexed and polarization combined 975 nm diode-stacks is reported. Up to 188 W of continuous-wave output at 1.57 microm was generated with a beam-quality factor (M;2) of 1.9 and an overall slope efficiency with respect to launched pump power of 41% (and 43% for output powers <120W). Tunable operation was demonstrated by use of an external cavity containing a diffraction grating and a maximum output power of 108 W at 1538 nm was generated for a launched pump power of ~ 336 W. The operating wavelength was tunable from 1531 to 1571 nm, with >100W output power over a tuning range of 36 nm from 1532 nm to 1568 nm.

83-W Single-Frequency Narrow-Linewidth MOPA Using Large-Core Erbium–Ytterbium Co-Doped Fiber

We demonstrate a continuous-wave (CW) single-frequency narrow-linewidth laser at 1552 nm with an output power of 83 W using a master-oscillator power amplifier configuration. A seed from an all-fiber distributed feedback-laser with a linewidth of 13 kHz was polarization scrambled and boosted through a chain of amplifiers in an all-fiber configuration. The last amplification stage consisted of a highly efficient cladding-pumped large-core erbium-ytterbium co-doped fiber which helped increase nonlinear thresholds.

A new design approach for fiber DFB lasers with improved efficiency

The standard distributed feedback (DFB) laser optimization method is critically investigated and a new design approach based on the effective cavity length is presented. By applying this method in an erbium-ytterbium co-doped fiber, the pump-to-signal conversion ratio is increased by 40% for the same total device length and pumping conditions. The laser with the proposed design is produced and the theoretical results are verified by the experimental work.

Polarization-resolved intensity noise in erbium-ytterbium codoped fiber lasers

The intensity-noise properties and polarization dynamics of a two-polarization Er:Yb codoped fiber laser are investigated and discussed. For a laser without polarization control, the low-frequency relative intensity noise reaches a minimum of approximately −90 dB/Hz. Polarization-sensitive detection reveals that the low-frequency intensity noise is influenced by a strong resonance associated with anticorrelated intensity fluctuations of the orthogonal linearly polarized modes. The frequency of the resonance varies linearly with laser power and leads to an increase in low-frequency noise of more than 45 dB for the polarized output of the laser.

A 43-W&amp;lt;tex&amp;gt;$C$&amp;lt;/tex&amp;gt;-Band Tunable Narrow-Linewidth Erbium–Ytterbium Codoped Large-Core Fiber Laser

The authors report a widely tunable and highly efficient cladding-pumped erbium-ytterbium codoped large-core fiber laser, generating up to 43 W of output power at /spl sim/1.5 /spl mu/m with a narrow linewidth (0.16-nm full-width at half-maximum) and a good beam quality (M/sup 2/<1.7). By use of a tunable narrow-band fiber Bragg grating, the laser wavelength was tuned from 1532 to 1567 nm, limited upwards by the tuning range of the fiber grating. The overall slope efficiency was 32% with respect to launched pump power.

High-power and tunable operation of erbium-ytterbium co-doped cladding-pumped fiber lasers

We describe erbium-ytterbium co-doped fiber lasers in different free-running and tunable configurations. The lasers were cladding-pumped by high-power multimode diode sources. We compare pumping at 915 and 980 nm. With a free-running laser, we obtained slope efficiencies of up to 50% with 915-nm pumping and 38% with 980-nm pumping, with respect to absorbed pump power. We reached a double-ended output power of 16.8 W from the free-running laser. Thanks to a high rare-earth concentration and a small inner cladding area (possible with the high-brightness pump sources we used), the operating pump absorption of the fiber reached 8 dB/m. With such high absorption, short fibers with high nonlinear thresholds are possible even with cladding pumping. The tunable fiber laser had a tuning range from 1533 to 1600 nm and emitted 6.7 W of output power at 1550nm in a high-brightness, single-polarization, narrow linewidth beam.