Radial velocity measurements errors caused by lighting instabilities severely limit the precision improvement in instruments; however, fiber scrambling is an effective method to enhance the stability of instrumental illumination. To provide a reliable experimental reference for the operation of a high resolution spectrograph upgrade and a new high precision radial velocity instrument design, the near field and far field scrambling properties of a single circular fiber, single octagonal fiber, circular-octagonal-circular fiber cascade connection system, double circular fiber scrambler, circular-octagonal hybrid double-fiber scrambler, and double octagonal fiber scrambler were studied in detail. The results showed that the octagonal fiber improved the near field scrambling compared to single circular fiber, the double-fiber scrambler could improve both near field and far field scrambling, and the double octagonal fiber scrambler optimally performed for both near field and far field. Furthermore, the prototypes of the double-fiber scramblers, including ball lens system and twin lens system, were also assessed herein. The throughput was observed to be 55% and 80%, respectively.