Long-wavelength-band Er3+-doped fiber amplifierincorporating a ring-laser as a seed signal generator

摘要

A novel dual-stage architecture for long-wavelength-band (L-band)nerbium-doped fiber amplifier, which incorporates a gain-clampednamplifier based on a ring-laser feedback as a seed signal generator innthe first stage is described. This technique has elevated the intensitynof a short-wavelength amplified spontaneous emission (ASE) by 29%, fromn11.3 mW of ASE power to 14.6 mW with a feedback lasing at 1560 nm. Thisnstrong laser then improves the L-band gain enormously, as large as 17.1ndB and noise figures are lower than 4.8 dB for the entire signal rangenin the flat-gain operation. The seeding signal reduces pump-to-ASEnlosses in the second stage to 38% compared to a conventional amplifiernwithout feedback. Noise figure penalties are negligible due to efficientnlow-noise characteristics in the first stage. The proposed amplifiernprovides 25 dB gain for 50 wavelength-division-multiplexed signals atn-30 dBm/ch with gain flatness less than 1.1 dB with only 980 nm pumping