method for manufacturing preform for photonic band gap fiber, method for manufacturing photonic band gap fiber, preform for photonic band gap fiber, and photonic band gap fiber
光子帶隙光纖預製棒的製造方法,光子帶隙光纖的製造方法,光子帶隙光纖預製棒,光子帶隙光纖
production method of optical fiber preform, and production method of optical fiber