J.T. Kringlebotn

Er(3+):Yb(3+)-codoped fiber distributed-feedback laser.

We report what is to our knowledge the first fiber distributed-feedback laser using a single Bragg grating at 1.5 microm written directly into a 2-cm-long Er(3+)-doped fiber codoped with Yb(3+). We obtained robust single-frequency operation by either using one end reflector or locally heating the center of the grating to create the necessary phase shift.

Stable single-frequency traveling-wave fiber loop laser with integral saturable-absorber-based tracking narrow-band filter.

We demonstrate stable single-frequency and polarization operation of a traveling-wave, Er(3+)-doped fiber loop laser by incorporating an unpumped Er(+3)-doped fiber section butted against a narrow-band feedback reflector. The saturable absorber acts as a narrow bandpass filter that automatically tracks the lasing wavelength, thus ensuring single-frequency operation. Output powers up to 6.2 mW at 1535 nm were obtained for launched pump powers of 175 mW at 1064 nm. At this output, the relative intensity noise was less than -112 dBy/Hz at frequencies above 200 kHz and a laser linewidth of less than 0.95 kHz, whereas the lasing frequency was observed to drift slowly (~170 MHz/h) because of environmental effects.

Polarimetric Er(3+)-doped fiber distributed-feedback laser sensor for differential pressure and force measurements.

We propose and demonstrate a polarimetric Er(3+) -doped fiber distributed-feedback laser sensor in which a force applied transversely along the fiber laser induces a birefringence that gives rise to a change in the beat frequency between the two orthogonally polarized laser modes. We measure a sensitivity of ~9.6 GHzysNymmd, a wide dynamic range with stable two-mode operation for frequency separations up to 50 GHz, and high sensor resolution owing to the narrow beat frequency bandwidth of <10 kHz. The temperature sensitivity is dominated by the temperature dependence of the inherent birefringence, which was measured to be -130 kHz/ degrees C. The sensor permits independent pressure-force and temperature measurements.

Efficient diode-pumped single-frequency erbium:ytterbium fiber laser

We report a 7.6-mW single-frequency fiber laser operating at 1545 nm, using for the first time an Er/sup 3+/:Yb/sup 3+/ doped fiber and a fiber grating output coupler. The laser did not exhibit self-pulsation, which is a typical problem in short three-level fiber lasers, and had a relative intensity noise (RIN) level below -145.5 dB/Hz at frequencies above 10 MHz. The linewidth of the laser was limited by the relaxation oscillation sidebands in the optical spectrum and was typically less than 1 MHz.<<ETX>>

Continuous and discrete wavelength tuning in Er:Yb fiber Fabry–Perot lasers

Continuous and discrete single-frequency tuning in the 1.5-μm wavelength region are demonstrated by incorporation of erbium:ytterbium phosphosilicate fibers in single and compound fiber Fabry–Perot cavity configurations. Continuous wavelength tuning was obtained over 3.3 nm in a single-cavity laser of 218-μm cavity length. Discrete wavelength tuning was achieved over 9.59 nm in a compound-cavity laser having a 2-mm gain section.