Laser signal intensity is resonantly enhanced within a laser cavity to be greater than a pump intensity. This enables the suppression of excited-state absorption and is applicable to terbium-doped fiber lasers, lambda-type materials, or other materials used in lasers. In other embodiments, ESA is suppressed by de-populating the higher excited state using a resonant cavity.

Ultrashort pulse fiber amplifier having a pulse width from 200 ps to 200 fs comprising a rare earth oxide doped multicomponent glass fibers for laser amplification, including a core and a cladding, the core comprising at least 2 weight percent glass network modifier selected from BaO, CaO, MgO, ZnO, PbO, K.sub.2O, Na.sub.2O, Li.sub.2O, Y.sub.2O.sub.3, or combinations; wherein the mode of the core is guided with step index difference between the core and the cladding, a numerical aperture of the fiber is between 0.01 and 0.04; core diameter is from about 60 microns to about 150 microns, and a length of the gain fiber is shorter than 60 cm.

A multi-wavelength laser system includes a first fiber laser having a first cavity mirror and a first output coupler, a first optical coupler configured to receive light from the first output coupler, a second fiber laser having a second cavity mirror and a second output coupler, and a second optical coupler configured to receive light from the second output coupler. The multi-wavelength laser system also includes a spectral beam combiner configured to receive first output light from the first optical coupler, receive second output light from the second optical coupler, combine the first output light and the second output light, and form a multi-wavelength output beam.

An example optical system architecture includes a diode laser source having an optical fiber. The diode laser source is configured to generate an optical signal having a main mode and side longitudinal modes and to output the optical signal along an optical path. An optical filter is in the optical path. The optical filter is configured to receive at least part of the optical signal, to output the main mode along the optical path, and to suppress the side longitudinal modes at least in part. One or more optical amplifiers are in the optical path after the optical filter. The one or more optical amplifiers are configured to receive at least part of the main mode, to amplify the at least part of main mode, and to output an amplified version of the at least part of main mode along the optical path.

An optical system, apparatus, or method can comprise or implement a seed module to generate and output electromagnetic radiation at a predetermined amplitude and at a predetermined wavelength. The seed module can include at least one non-hollow core optical fiber and at least one hollow core optical fiber. One at least one non-hollow core optical fiber can be optically coupled to one at least one hollow core optical fiber. The non-hollow core optical fiber and the hollow core optical fiber may receive and pass electromagnetic radiation emitted from a laser diode or amplifier.

The present invention discloses a high-peak-power single-frequency narrow-linewidth nanosecond fiber laser based on a triangular pulse, wherein the laser includes: pulsed laser generated by the laser seed injecting into a first power pre-amplifier through a first isolator, and then injecting into a second pre-amplifier and then injecting into a power amplifier; wherein triangle-shaped pulsed laser with fast rising edge is obtained by using electro-optic and acousto-optic modulator to modulate continuous wave single-frequency laser or a single-frequency semiconductor laser directly modulated by radio frequency signal; single-frequency triangle-shaped pulsed laser is employed as the laser source according to the characteristics of narrow intrinsic linewidth and suppression of linewidth broadening caused by SPM, and the power of pulsed laser is amplified through the MOPA system.

A femtosecond pulse laser apparatus includes a pump light source configured to provide a pump light, a gain medium configured to obtain a gain of a laser light using the pump light, a first curved mirror and a second curved mirror, which are provided at both sides of the gain medium, an output mirror configured to transmit a portion of the laser light and reflect the other portion of the laser light to the gain medium, a mode locking portion configured to generate a femtosecond pulse of the laser light, and an acoustic wave generator configured to provide an acoustic wave into the gain medium so as to adjust self-phase modulation of the laser light.

Apparatus for providing optical radiation (9), which apparatus comprises; a first seed source (1) for providing first seeding radiation (11); a second seed source (2) for providing second seeding radiation (12); a coupler (3) connected to the first seed source (1) and the second seed source (2) for coupling the first seeding radiation (11) and the second seeding radiation (12) together; and at least one amplifier (4) for amplifying the first seeding radiation (11) and the second seeding radiation (12).

The present disclosure provides a tunable broadband random optoelectronic oscillator, including: a laser light source configured to generate continuous laser light; a positive feedback loop formed by an intensity modulator, an optical circulator, an optical filter, an optical amplifier, a photodetector, an electric filter and an electric amplifier connected in sequence, wherein the positive feedback loop is configured to receive the continuous laser light to generate a microwave signal and achieve an optic-electro/electro-optic conversion; a Raman laser configured to generate Raman pump light; a wavelength division multiplexer having a first input terminal connected to the Raman laser and a second input terminal connected to the optical circulator; and a dispersion compensation fiber connected to an output terminal of the wavelength division multiplexer; wherein forward transmission laser light passing through the optical circulator and the Raman pump light are coupled into the dispersion compensation fiber through the wavelength division multiplexer.

A fiber optic assembly includes: a gain fiber configured to output signal light; a first taper configured to expand the signal light output by the gain fiber; and a reversing prism configured to receive counter-pumping light and output the counter-pumping light into the first taper. The first taper is further configured to direct the counter-pumping light towards the gain fiber.