Contentionless Twin 8×24 WSS with Low Insertion Loss

A contentionless Twin 8×24 WSS has been designed and manufactured in prototype quantities. Measured insertion loss was between 3.3 dB and 6.8 dB for all port combinations, the lowest loss ever reported for a contentionless MxN WSS.

1. Introduction

Contentionless MxN Wavelength Selective Switch (WSS) will provide cost and performance benefits for next generation colorless, directionless and contentionless (CDC) ROADM networks [1], [2], resulting from improved scalability of add/drop ports and removal of EDFA arrays (which are required to overcome splitting losses in multicast switches). Current multicast switches are filterless and so any noise generated within the transceiver Tx will be combined in the MCS, degrading the end to end OSNR. A contentionless MxN WSS eliminates the performance degradation from out-of-band noise accumulation by virtue of the wavelength filtering in the WSS.