| 摘要 |
<p>Two terminals 2, 4 in towns A, B respectively are connected by an optical link 1. The link 1 comprises optical modules 14, 15 and spans 20, 22, 24 interconnecting the optical modules14, 15. The modules 14, 15 require the application of light of a first wavelength to operate. Light of a second wavelength is coupled into a span 20, 22 at or close to a terminal 2, 4 and is carried along the span 20, 22 to an optical module 14, 15. The light of the second wavelength is converted to the first wavelength during its carriage along the span 20, 22. <IMAGE></p> |
