Abstract

Although optical isolators are vital elements in large fiber-amplifier cascades, it would be desirable to eliminate isolators in smaller cascades, or decrease their number, both to reduce costs and to facilitate bidirectional transmission. However, when some or all isolators are removed from amplifier cascades, the number of significant residual Fabry- Perot resonators, caused by parasitic reflections, grows rapidly, generating rapidly rising levels of phase-induced intensity noise (PI1N).^1,2

© 1993 Optical Society of America