Aspects of the present disclosure describe techniques for fast stabilization of multiple controller beams with continuous integrating filter. For example, a method is described for intensity stabilization of laser beams (e.g., ion controller beams) in a trapped ion system, where the method includes applying a linear array of laser beams to respective ions in a linear array of ions in a trap, performing, in response to the laser beams being applied, parallel measurements on the ions, the parallel measurements including multiple, separate measurements on each of the ions to identify fluctuations in intensity in the respective laser beams at each ion, and adjusting the intensity of one or more of the laser beams in response to fluctuations being identified from the parallel measurements. A corresponding system for intensity stabilization of laser beams in a trapped ion system is also described.

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.

A sensing method for in-situ non-perturbing measurement of characteristics of laser beams at the exit of the laser beam delivery fiber tips include measuring power of a laser beam transmitted through delivery fiber tip in fiber-optics systems. A sensing devices for in-situ non-perturbing sensing and control of multiple characteristics of laser light transmitted through light delivery fiber tips includes a fiber-tip coupler comprised of a shell with enclosed delivery fiber having a specially designed angle-cleaved endcap and one or several tap fibers that are specially arranged and assembled at back side of the endcap and other variations. Methods and system architectures for in-situ non-perturbing control of characteristics of laser beams at the exit of the laser beam delivery fiber tips include fiber-tip couplers and sensing modules that receive laser light from tap fibers, and systems for optical processing to enhance light characteristics suitable for in-situ measurement.

Apparatus for modelocking a fiber laser cavity includes two variable retarder assemblies and a polarizing element. The variable retarder assemblies each have two electronically addressable elements and one fixed element. The first variable retarder assembly prepares a polarization state suitable for NPE modelocking to be launched into the fiber, and the second variable retarder assembly controls the polarization state after exiting the fiber, before being incident on the polarizing element. A control system controls the electronically addressable phase retarders in order to create and modify conditions for modelocking the fiber laser.

An object detection system uses a change in a linear polarization statistic between a first image at a first time and a second image at a second time to determine the presence or the likelihood of an object beneath a surface. The presence of the object may be determined by regions of anomalously high changes in the polarization statistic. The system may use a polarization change detection detector which may simultaneously capture images in multiple polarization channels. Further, the polarization change detection detector may be coupled with a laser interferometry system. Further, the polarization change detection detector may be used to capture a time series of images to determine the polarization decorrelation time for each pixel in the field of view to provide additional detail regarding an object detected beneath the surface.

A laser amplifier module having an enclosure includes an input window, a mirror optically coupled to the input window and disposed in a first plane, and a first amplifier head disposed along an optical amplification path adjacent a first end of the enclosure. The laser amplifier module also includes a second amplifier head disposed along the optical amplification path adjacent a second end of the enclosure and a cavity mirror disposed along the optical amplification path.

A fiber amplifier system including an optical component responsive to a seed beam and causing amplitude modulation that creates a non-uniform spectral transmission having peaks and nulls, and an actuator operable to shift the spectral transmission. The system further includes a fiber amplifier responsive to the seed beam and generating an amplified output beam and a beam sampler responsive to the output beam that provides a sample beam. A detector detects power fluctuations in the sample beam caused by the amplitude modulation, and generates a control metric identifying a magnitude of the fluctuations. A controller uses the control metric to control the actuator to cause it to make adjustments to the seed beam or to the optical component to cause the spectral transmission caused by the optical component to shift so that the peaks or nulls of the spectral transmission align with a center frequency of the seed beam.

A fiber amplifier system including a plurality of optical components in an amplification chain that are responsive to a seed beam and that cause frequency modulation (FM) to amplitude modulation (AM) conversion to the seed beam that creates a non-uniform spectral transmission having a transmission function, where one of the optical components is a fiber amplifier generating an amplified output beam. A programmable spectral filter is controlled to pre-distort the seed beam by applying an inverse of the transmission function that creates a net uniform transmission function by equalizing a net spectral transmission profile of the seed beam at an end of the amplification chain to reduce the amplitude modulation.

A sensing method for in-situ non-perturbing measurement of characteristics of laser beams at the exit of the laser beam delivery fiber tips include measuring power of a laser beam transmitted through delivery fiber tip in fiber-optics systems. A sensing devices for in-situ non-perturbing sensing and control of multiple characteristics of laser light transmitted through light delivery fiber tips includes a fiber-tip coupler comprised of a shell with enclosed delivery fiber having a specially designed angle-cleaved endcap and one or several tap fibers that are specially arranged and assembled at back side of the endcap and other variations. Methods and system architectures for in-situ non-perturbing control of characteristics of laser beams at the exit of the laser beam delivery fiber tips include fiber-tip couplers and sensing modules that receive laser light from tap fibers, and systems for optical processing to enhance light characteristics suitable for in-situ measurement.

A laser amplifier module having an enclosure includes an input window, a mirror optically coupled to the input window and disposed in a first plane, and a first amplifier head disposed along an optical amplification path adjacent a first end of the enclosure. The laser amplifier module also includes a second amplifier head disposed along the optical amplification path adjacent a second end of the enclosure and a cavity mirror disposed along the optical amplification path.