Abstract: A cladding-pumped gain optical fiber is provided. The cladding-pumped gain optical fiber includes a core transmitting a signal light; a first cladding covering the core and having an optical-gain dopant; a second cladding covering the first cladding for transmitting a pumping light; and a third cladding covering the second cladding for reflecting the pumping light.

Abstract: A wavelength-tunable mode-locked fiber laser system is provided and includes an optical cavity. The optical cavity outputs an output laser pulse having an adjustable principal wavelength, and includes a short-wavelength-pass filter, a polarization controller, an optical gain fiber and a fiber. The short-wavelength-pass filter produces an intracavity laser pulse. The fiber has a length, and connects the short-wavelength-pass filter, the polarization controller and the optical gain fiber in series. The optical cavity has an anomalous dispersion range and a net group-velocity dispersion being within the anomalous dispersion range due to the length of the fiber. The optical cavity causes the intracavity laser pulse to propagate therein for providing the output laser pulse, providing a first laser pulse, a second laser pulse and a third laser pulse to the short-wavelength-pass filter, the polarization controller and the optical gain fiber respectively, and adjusting the intracavity laser pulse.

Abstract: A cladding-pumped gain optical fiber is provided. The cladding-pumped gain optical fiber includes a core transmitting a signal light; a first cladding covering the core and having an optical-gain dopant; a second cladding covering the first cladding for transmitting a pumping light; and a third cladding covering the second cladding for reflecting the pumping light.

Abstract: A wavelength-tunable mode-locked fiber laser system is provided and includes an optical cavity. The optical cavity outputs an output laser pulse having an adjustable principal wavelength, and includes a short-wavelength-pass filter, a polarization controller, an optical gain fiber and a fiber. The short-wavelength-pass filter produces an intracavity laser pulse. The fiber has a length, and connects the short-wavelength-pass filter, the polarization controller and the optical gain fiber in series. The optical cavity has an anomalous dispersion range and a net group-velocity dispersion being within the anomalous dispersion range due to the length of the fiber. The optical cavity causes the intracavity laser pulse to propagate therein for providing the output laser pulse, providing a first laser pulse, a second laser pulse and a third laser pulse to the short-wavelength-pass filter, the polarization controller and the optical gain fiber respectively, and adjusting the intracavity laser pulse.