A coherent fiber array laser power projection system scalable to large number of subapertures and includes sensors that produce signals dependent upon beam characteristics, and controllers configured to control beam characteristics to achieve either phasing of outgoing beams at transmitter plane or coherent beam combining at a remote target or both.

The present disclosure provides an ultrafast laser that outputs multiple wavelengths. The ultrafast laser includes a fundamental frequency ultrafast laser unit, an optical beam splitting and polarization controlling unit, a multiple frequency unit, and an optical beam combining unit. The fundamental frequency ultrafast laser generates a multiple frequency ultrafast laser by the multiple frequency unit, such as double frequency light, triple frequency light, etc., and the optical beam combining unit makes the fundamental frequency light and the double frequency light output in a light outlet, the controlling unit controls the wavelength of the laser of the light outlet by controlling the polarization state of the laser. The ultrafast laser of the present disclosure can realize fast switching output among the fundamental frequency light and multiple frequency light, and output of combined pulse fundamental frequency light and double frequency light. The present disclosure also provides a strong powerful laser tool.

Various example embodiments relate to active optical fibers and devices comprising active optical fibers. A section of an active optical fiber may comprise an active core doped with at least one rare-earth element. The active core may have a first refractive index and be configured to support a single mode operation of an optical signal. The section of the active optical fiber may further comprise at least one cladding layer having a second refractive index. The second refractive index may be less than the first refractive index. Birefringence of the active core may be less than 10.sup.-5. Fiber lasers and power amplifiers comprising the section of the active optical fiber are also disclosed.

An ultrastable laser system is based on a polarization-maintaining optical fiber. The ultrastable laser system comprises a laser device; acousto-optic modulators, a first beam splitter, a polarizer, an optical fiber interferometer comprising a second beam splitter, an optical fiber delay line, a third acousto-optic modulator, and a beam combiner; a beam combiner, a polarization beam splitter, photoelectric detectors, a frequency synthesizer, frequency mixers, a servo feedback circuit and a piezoelectric ceramic. The temperature interference is eliminated based on the characteristic that refractive indexes of a fast axis and a slow axis of the polarization-maintaining optical fiber differently change with a temperature, a vacuum structure can be avoided, and the ultrastable laser system has low cost, small system, simple structure and high signal stability.

Methods and apparatuses for determining the polarization state and for providing polarization control in optical fiber lasers and amplifiers. One embodiment of the invention is an optical fiber amplifying system including a circulator (260) having a first optical port (260a), a second optical port (260b) that is configured to output radiation received from the first optical port, and a third optical port (260c) that is configured to output radiation received from the second optical port; one or more amplifier stages (216) connected in series, together having an optical input (216a) optically coupled to the second port of the circulator, and an optical output (216b); and a polarization detector (240) having an optical input optically coupled to the third port of the circulator. Thereby the polarization state of the amplified radiation can be determined using radiation backscattered from the amplifying stage.

The present invention provides a burst-laser generator using an optical resonator which produces high pulse-strength of burst-laser in order to conduct laser Compton scattering, comprising: a self-oscillation amplifying optical loop-path and an external optical resonator to burst-amplify laser, wherein, laser supplied by an exciting laser source is self-oscillation amplified with the self-oscillation amplifying optical loop-path and further burst-amplified with the external optical resonator.

Multi-Channels coherent beam combining (CBC) using a mechanism for phase and/or polarization locking that uses a reference optical beam and an array of optical detectors each detector being configured and located to detect overall intensity of an optical interference signal caused by interfering of the reference beam and a beam of the respective channel, where the fast intensity per-channel detection allows simultaneous and quick phase/polarization locking of all channels for improving beam combining system performances.

A tunable narrow-linewidth photo-generated microwave source based on polarization control includes a high-reflectivity fiber grating, a high-gain fiber, a low-reflectivity polarization-maintaining fiber grating, a stress adjusting device, a single-mode semiconductor pump laser, an optical wavelength division multiplexer, a polarization beam splitter, a polarization controller, an optical coupler, and a photoelectric detector. Birefringence distribution in the low-reflectivity polarization-maintaining fiber grating is controlled by adjusting a stress magnitude of the stress adjusting device to the low-reflectivity polarization fiber grating, thereby controlling a laser frequency working in different polarization modes in a resonant cavity, and a tunable narrow-linewidth photo-generated microwave source is generated by a beat-frequency technology using a dual-wavelength narrow-linewidth laser with variable frequency intervals.

Multi-Channels coherent beam combining (CBC) using a mechanism for phase and/or polarization locking that uses a reference optical beam and an array of optical detectors each detector being configured and located to detect overall intensity of an optical interference signal caused by interfering of the reference beam and a beam of the respective channel, where the fast intensity per-channel detection allows simultaneous and quick phase/polarization locking of all channels for improving beam combining system performances.

Multi-Channels coherent beam combining (CBC) using a mechanism for phase and/or polarization locking that uses a reference optical beam and an array of optical detectors each detector being configured and located to detect overall intensity of an optical interference signal caused by interfering of the reference beam and a beam of the respective channel, where the fast intensity per-channel detection allows simultaneous and quick phase/polarization locking of all channels for improving beam combining system performances.