<title>Homodyne crosstalk analysis of integrative OADM/OXC in WDM optical transport networks</title>

Abstract

Optical add/drop multiplexer (OADM) and optical cross-connect (OXC) are key network elements in wavelength division multiplexing (WDM) optical transport networks. Homodyne crosstalk, due to the non-ideal performance of the demultiplexers/multiplexers and the switches, is introduced in OADMs and OXCs and causes system performance degradation. In this paper, we propose a low crosstalk structure for integrative OADM/OXC that implements the function of OADM and OXC simultaneously. For joined adding and dropping, we place a set of 2 X 2 switches between the demultiplexers and the cross-connect array instead of using larger dimensional cross- connect array. We also theoretical compared the impact of the homodyne crosstalk in the proposed structure and in the conventional integrative OADM/OXC. Simulation result shows that the power penalty caused by homodyne crosstalk can be decreased significantly in the proposed structure. Since the add/drop and cross-connect state of the integrative OADM/OXC changes from time to time for reconfiguration and restoration and the polarization state of the signals varies constantly due to the thermal and mechanical fluctuations, we statistically analyzed the power penalty distribution. It can be obtained that the power penalty in the proposed structure distributes in a smaller range. This is very helpful to the planning and design of the optical transport networks.