State of the art and future ofWDM transmission

After briefly recalling the recent history of optical communication, this paper describes the structure of aWDM system, the critical parameters involved in its design, the different degradations which the transmitted signal suffers from, the state of the art and the future evolutions ofWDM transmission technology. Some recent results are given to illustrate the best results obtained in the research laboratories.     

Intervalence band absorption coefficient measurements in bulk layer, strained and unstrained multiquantum well 1.55 mu m semiconductor lasers

Measurements are reported of intervalence band absorption (IVBA) coefficient k/sub 0/ in three types of active layer structure: bulk, unstrained (MQW) and strained multiquantum wells. The IVBA measurements are performed by observing the spontaneous emission from the uncleaved facets of DCPBH Fabry-Perot lasers. k/sub 0/=(3.7+or-0.3)*10/sup -17/ cm/sup 2/ is obtained for bulk, (1.4+or-0.2)*10/sup -16/ cm/sup 2/ for MQW unstrained and (3.5+or-0.3)*10/sup -17/ cm/sup 2/ for strained MQW structures.<>