Erbium-ytterbium Co-doped Fiber Laser Research Articles

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<tex>$C$</tex>-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.