Research On Array Optical Fiber Localization And Detection Methods

Integral field spectroscopy has become an important technology in modern astrophysical observation.Integral field of view spectroscopy has become an important technology in modern astrophysical observation.By analyzing the sampled astronomical spectra,abundant information about the characteristics of celestial bodies can be got.Integrated field unit?IFU?,as an important device for astrophysical three-dimensional observation technology,can obtain three-dimensional spectral information on the two-dimensional focal plane,and can carry out image collection and spectral collection simultaneously.At present,the common structure of IFU is the combination of microlens array and array optical fiber.As the optical transmission medium on IFU,array optical fiber is directly related to its performance.Therefore,it is an indispensable part of IFU manufacturing process to locate the fiber array and evaluate its performance after positioning.This thesis focuses on how to accurately position the fiber array without affecting its performance.And the positioning accuracy and performance of the fiber are tested.Based on the theory of step mode multi-mode fiber transmission optical waveguide,the IFU model is analyzed,and several parameters related to optical fiber emission light spots are expounded by combining the focal ratio degradation theory.The processing methods of IFU microlens end and pseudo-slit end are discussed.The quartz plate with mircopores method was selected at the end of the microlens.The orientation method of quartz V-grooves is selected at the end of the pseudo-slit,and the arrangement method of fiber dislocation double-row slit is proposed.The optical fiber with the fixed position was completely polished,then the quartz plate with mircopores and the microlens array were aligned and bonded.The precise orientation of the fiber array was successfully completed.The optical fiber efficiency and the optical fiber overall focal ratio are tested.Before the microlens array was installed,the overall efficiency of the optical fiber was between 86%and91%,and the effective value?calculated by RMS?was 88.7%,far beyond the requirements of the telescope.After installing the microlens array,the effective value of the ejection efficiency decreased by 2.7%.However,considering that the reverse reflection of microlens will increase the output Angle and reduce the efficiency,it is also enough to meet the standard of normal operation.Using spot marking method got the output focal ratio of two pseudo-slit ends isF/#_out1=7.32andF/#_out2=7.23,and the linearity is R²=0.999.Using overall treatment of light spot image method got the focal ratio of the end of no.2 pseudo-slit is F/#_out2=6.94,and the linearity is R²=0.997.The measurement results of both methods show that the IFU output focal ratio degradation can meet the normal working demand.The optical fiber alignment accuracy is detected,the optical fiber image is taken by CCD,the coordinates of each optical fiber are calculated by image processing method,the effective values of spot offset are represented by root mean square?RMS?,the measured RMS values are not greater than 5 microns,reaching the normal operating index range of FASOT telescope.Therefore,according to the results,it can be concluded that the arrangement accuracy of IFU array optical fiber meets the normal use requirements of IFU.