ABSTRACT
For optical fibers exhibiting a radially symmetric refractive index profile, there exists an analytical relation that connects waveguide dispersion and the Petermann-II mode field radius. We extend the usefulness of this relation to the nonradially symmetric case of microstructure fibers in the anomalous dispersion regime, yielding a simple relation between dispersion and effective mode field area. Assuming a Gaussian mode distribution, we derive a fundamental upper limit for the effective mode field area that is required to obtain a certain amount of anomalous waveguide dispersion. This relation is demonstrated to show excellent agreement for fiber designs suited for supercontinuum generation and soliton lasers in the near infrared.
ABSTRACT
We demonstrate femtosecond operation of a Nd-doped mi-crostructure fiber laser. The fiber provides gain and anomalous dispersion at the lasing wavelength of 1.06 microm and enables the construction of short and simple cavity designs. The laser is passively mode-locked by the combined action of a saturable absorber mirror, fiber nonlinearity, and dispersion and produces transform limited sub-400-fs pulses with a pulse energy as high as 100 pJ.
ABSTRACT
We demonstrate passive mode-locking of a microstructured fiber laser for the first time. The Nd-doped microstructured fiber exhibits a reduced dispersion at 1060 nm. A semiconductor saturable absorber mirror is used for passive mode-locking. Stable pulse formation with a pulse duration of about 26 ps and a pulse energy of 0.7 nJ is observed.