The ASE-Free version of our standard double-clad erbium/ytterbium co-doped fiber is specifically engineered to minimize ASE around 1 µm, effectively suppressing parasitic ytterbium emission while enabling higher output power, stable amplification, and excellent optical efficiency. Optimized for high-power optical amplifier designs, this fiber delivers high output power together with excellent gain flatness across the extended C-band, making it an ideal gain medium for single channel and multichannel applications.