System Limitations for Fiber Amplifier Cascades,
Abstract
The performance, of an amplifier cascade system is taken to be the product of transmission bit rate, B, and transmission distance, L. In amplifier cascade systems using the IM/DD scheme, signal spontaneous beat noise, spontaneous-spontaneous beat noise and shot noise are present in addition to receiver thermal noise, while local oscillator shot noise and local oscillator-spontaneous beat noise are additional factors in coherent systems. Signal-spontaneous and spontaneous-spontaneous beat noises generally predominate in IM/DD systems if many cascaded amplifiers are used. Conversely, in coherent systems, local oscillator-spontaneous beat noise predominates. In such cases, system performance is approximated by B X L = fmod(SNR, /) X (PS/NF), where fmod(SNR, /) is a function of required SNR and amplifier spacing, /, depending on the mod/demod scheme, Ps is the amplifier output power, and NF is the amplifier noise figure. Therefore, the system performance depends on amplifier spacing and amplifier performance given as PS/NF. As the spacing decreases and/or amplifier performance increases, system performance increases. However, it is limited by four conditions: (1) Fiber dispersion, (2) Amplifier performance, (3) Noise accumulation, and (4) No cascaded amplifier.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 22, 1992
- Accession Number
- ADP006990
Entities
People
- Takeshi Ito
Organizations
- NTT, Inc.