Experimental research on the degree of clustering in Bi3+-Ga3+ co-doped high concentration Er3+-doped silica-based fiber

In order to obtain high-concentration doped erbium ions in silica-based fiber, we manufactured Er3+-Bi3+-Ga3+ co-doped fiber using MCVD and solution doping technique. The concentration of Er3+ in the fiber was about 5.24×1025/m3. We described a new method to measure the degree of clustering in the Er3+-Bi3+-Ga3+ co-doped fiber using fiber transmission experiment. Compared with other methods, the new method is simpler and more accurate. By the new method, the degree of clustering in Er3+-Bi3+-Ga3+ co-doped fiber was determined. It was shown that co-doped Bi3+-Ga3+ strongly increased the Er3+ solubility in the silica-based fiber.