A novel, to the best of our knowledge, cantilever construction design of an adaptive fiber-optics collimator (AFOC) based on piezoelectric bimorph actuators for tip/tilt control is introduced. With this new cantilever structure, an AFOC with a diameter of only 6 mm was developed, and the output laser beam deviation angle and resonance frequency of the device were measured. The experimental results show that this new AFOC can provide more than 1 mrad deflection angle at a 20 V driving voltage, and the first resonance frequency is about 500 Hz. Further, in order to verify whether the cantilever structure can be used in a high-power fiber collimator, a high-power X − Y positioner with an 8 mm diameter fiber end cap was developed. The experimental results show that the high-power X − Y positioner can output more than 2 kW laser power and provide about 330 µm displacement of the fiber end cap in the X direction and about 770 µm in the Y direction at a 150 V driving voltage.

Optical signal receiver is a crucial element in free space optical communication (FSOC) system. Single-mode fiber (SMF) is commonly utilized in receivers for connecting with the subsequent optical fiber communication devices. However, the conventional SMF's tiny core size and the random drift of the signal laser's optical axis cause small field of view, and the optical signal acquisition and coupling issues was limited. Herein, a wide field of view optical signal receiver via pump and signal combiner was proposed and demonstrated. The experimental results show that the detection field of view of the pump and signal combiner with a 20/400 μm double-clad fiber increased about 40 times, compared with using a 6/125 μm SMF. Additionally, with the home-build adaptive fiber tip controller, the wide detection field of view can further improve the stability of optical signal receiving in the dynamic optical signal receiving system.

Coherent beam combination of fiber lasers is considered to be a promising technology to obtain high-brightness laser. In tiled-aperture coherent beam combination, in order to obtain the best combination effect, a high fill factor is required for the beam array output from the fiber collimators. Thus, the collimator array must be closely arranged and each single-mode Gaussian beam must be truncated, which brings great difficulties to design a fiber collimator. We propose a scheme of fiber collimator based on rod lens, which compares to the fiber collimator with the thin lens, has the following advantages. Firstly, rod lenses for beam collimation can be arranged in an array without a frame to get a high fill factor of fiber collimators. Secondly, the single-mode Gaussian beam from fiber can be truncated in any proportion to get a good result of coherent beam combination. Thirdly, almost all of the laser energy output from a fiber include the stray light with the large NA is emitted into space outside the collimator by the rod lens. Fourth, the structure of fiber collimator with the rod lens is simple, which makes it easy to build a large number of fiber lasers array. In this paper, we have developed a rod lens colllimator and carried out the preliminary experiments, the results show that the rod lens collimator can emit a collimated beam with the good beam quality, and all stray light with the large NA in the collimator can be exported to space.