Control of dispersion in a femtosecond ytterbium laser by use of hollow-core photonic bandgap fiber.

We demonstrate the use of photonic bandgap fiber for dispersion compensation in a short-pulse fiber laser. The anomalous dispersion provided by the photonic bandgap fiber enables us to construct a femtosecond fiber laser at 1 micron wavelength without prisms or diffraction gratings. The laser is self-starting and produces 160-fs pulses with 1-nJ energy, and represents a significant step toward all-fiber devices capable of much higher pulse energies.