Because the adopted N layers of rare-earth ion-doped ring-core optical fibers exist in a common central cladding region, the pumping efficiency is greatly improved.

由于采用的N层掺稀土离子环芯光纤存在一个共同的中心包层区，因此极大提高了泵浦效率。

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Private-housing prices in the city-state's core central region rose 0.6% in the second quarter, compared with a 0.6% fall in the January-April period.

WSJ: Singapore Home Prices Swing Higher