Long-wavelength-band Er3+-doped fiber amplifier incorporating a ring-laseras a seed signal generator

A novel dual-stage architecture for long-wavelength-band (L-band) erbium-do ped fiber amplifier, which incorporates a gain-clamped amplifier based on a ring-laser feedback as a seed signal generator In the first stage is descr ibed herein, This technique has elevated the intensity of a short-wavelengt h amplified spontaneous emission (ASE) by 29%, from 11.3 mW of ASE power to 14.6 mW with a feedback lasing at 1560 nm, This strong laser then improves the L-band gain enormously, as large as 17.1 dB and noise figures are lowe r than 4.8 db for the entire signal range in the flat-gain operation. The s eeding signal reduces pump-to-ASE losses in the second stage to 38% compare d to a conventional amplifier without feedback. Noise figure penalties are negligible due to efficient low-noise characteristics in the first stage. T he proposed amplifier provides 25 dB gain for 50 wavelength-division-multip lexed signals at - 30 dBm/ch with gain flatness less than 1.1 db with only 980-nm pumping.