We present a dispersive interferometry of optical frequency comb for simultaneous measuring absolute distance and angle. The reconfigured Michelson interferometer can emit two parallel measured beams and one reference beam. The three pulse beams interfere with each other, and the interference spectrum is sampled by a spectrometer. It is simultaneously modulated by the three optical path differences, which contains the information of absolute distance and angle and can be demodulated by a Fourier transform. By making an angle measurement comparison with a calibrated turntable, the proposed method shows that the obtained mutual agreement is better than 3 arcsec in the range of ±5°. The commercial interferometer and autocollimator are used to verify the feasibility of the proposed method for precision distance and angle measurement.

Laser-tracking measurement systems (laser tracker) have been playing a critical role in large-scale 3D high-precision coordinate measurement. However, the existing visual guidance of laser trackers is still limited by the disadvantages of operator-dependence, small-angle view field, time-consuming laser-guided process. This paper presents an automatic guidance method for laser trackers based on the rotary-laser scanning angle measurement technology. In this method, a special target consisting of six photoelectric receivers and a retroreflector is integrated into the rotary-laser scanning transmitter’ coordinate systems. Real-time constraints calculated by the proposed method would provide the coordinates of the target in a laser tracker coordinates system for guidance. Finally, the experimental results verified the automatic re-establish of sightline can be realized in horizontal 360° angle field within tens of arc-seconds, and this method is robust against the fast movement of the target.

A perfect spatial overlap with multiple beams of different wavelengths is a prerequisite for multi-wavelength interferometry. Beam combination with the help of fibers seems to be an interesting method for this. We investigated three different types of fiber components, multi-mode wavelength division multiplexers (MM-WDMs), single-mode wavelength division multiplexers (SM-WDMs), and endlessly single-mode polarization maintaining photonic crystal fibers (PM-PCFs). All three seem potential candidates for a perfect spatial overlap of laser beams separated by an octave, i.e. fundamental and harmonic beams. We performed an experimental study on the impact of these components on polarization, wavefront, and coherence. These properties are essential for high-accuracy interferometry. As a test system, we used the fundamental and second harmonic beam of a Nd:YAG laser system at 1064 and 532 nm as a popular system in two-color interferometry for intrinsic refractive index compensation. The experimental results show the potential of PM-PCFs for this challenging application.

提出了一种利用45°半透半反分束镜和角锥反射器实现两路光纤激光器的能量相互注入，从而获得相干合成激光输出的新方法，分析了其锁相原理.在实验上成功实现了两路独立振荡双包层光纤激光器的互注入锁相输出，在远场观察到了清晰稳定的干涉条纹（可见度约0.57），获得了超过10W的相干合成激光输出，功率合成效率约为76%.实验表明，这种互注入锁相方法可以在更高功率条件下运行，是光纤激光相干合成领域一种有前途的新技术.

Traceable calibration of kilometer-scale geodetic baselines with sub-millimeter accuracy is crucial for advancing large-scale length standards, particularly geographic information framework construction. This study presents a differential dual-comb ranging system—specifically designed for high-precision geodetic baseline calibration—incorporating two repetition-rate-stabilized resonators. Additionally, a dual-channel fiber-optic configuration is developed for dual-comb ranging. For outdoor distance measurement, where inevitable air disturbances induce signal variations, the amplitude triggering method is used to acquire the measured signal. Indoor experiments with the proposed system achieved 8.2 µm accuracy at 70 m, validated against a length standard. Outdoor measurements along a 1.2-km geodetic baseline showed 0.13 mm reproducibility between two separate tests, with the terminal point standard deviation constrained to 23.4 µm.