介绍了一种特殊的天文光纤模式转换器，称之为光纤刷。研究了这种天文光纤模式转换器的制作技术及各纤芯之间的耦合特性。由于天文成像低色散的要求，研究了这种光纤刷的超模耦合特性，并且为了比较不同超模的发散情况，分别计算了光纤刷的近场超模和远场超模。通过远场超模发散半径的比较，发现同相超模具有最小的发散角和最好的光束质量。研究结果对类似光纤模式转换器件的研究具有启发意义。

A special kind of astronomical fiber device which is called as optical fiber brush is introduced. Its fabricating technique and the supermode coupling characteristics are investigated. Due to the low dispersion of astronomical imaging, the supermode coupling charateristic of the optical fiber brush is studied. In order to investigate and compare the divergence angle of different supermodes, near-field and far-field distributions of them are also calculated. Comparing with the far-field mode radius, it′s found that the in-phase supermode has the least divergence angle and the best beam quality. The research result can be helpful to investigate simillar fiber mode converters.