STUDIES ON SEMICONDUCTOR OPTICAL AMPLIFIERS FOR LINE CAPACITY EXPANSION IN PHOTONIC SPACE-DIVISION SWITCHING-SYSTEM

Photonic space-division (SD) switching systems are promising and practical for providing future broad-band services. For expanding line capacity of such a switching system, application of optical amplifers, especially traveling-wave semiconductor amplifiers (TWA's), is indispensable for compensating photonic switch matrix losses. This paper examines the problems associated with introducing TWA's to the photonic SD switching system. Experiments were carried out to clarify the TWA noise effect and interference between cascaded TWA's, using about 10-dB gain TWA modules. Possibillity of a 128-line photonic SD switching system, using current polarization independent LiNbO3 8 x 8 switch matrices, has been shown through the experiments. It has been also shown that the expected line capacity value for such a switching system exceeds 10(3).