OPTICAL DIGITAL CROSS-CONNECT SYSTEM USING PHOTONIC SWITCH MATRICES AND OPTICAL AMPLIFIERS

An optical digital cross-connect system (DCS) comprised of both photon ic switching networks and electric DCSs is proposed for applications i n network-failure restorations. Optical DCSs exhibit excellent charact eristics in restorations of multiple failures and when compared agains t their electrical counterparts, size-reduced apparatus can be expecte d. The design of DCSs for applications in metropolitan-area networks a re investigated and it is shown that such DCSs can be realized using L iNbO3 photonic switch matrices together with traveling wave optical am plifiers (TWA). With respect to the problem arising from the polarizat ion dependency of TWA gain, it was solved using the output power contr oller (APC) which is shown theoretically to cause no difficulty in the noise characteristics. The optical DCS is designed and manufactured u sing LiNbO3 switch matrices and TWA, by which its basic operation prop erties are verified. Using this trial system, it is confirmed that the network failures can be restored by changing the optical routes.