Twenty-wavelength, dual-receiver DWDM system: modeling and experiments

We present test results on a Philips DWDM system with a record capacity of 20 optical wavelengths. Each of the twenty optical wavelengths in the forward path of the test system was modulated by 200 MHz of data, to yield a cumulative forward capacity of 4 GHz, or 26 Gb/s when using 256-QAM. Modeling of the dominant impairments is also performed to determine the limitation of broadband DWDM systems. These impairments include SRS-induced crosstalk, chirp-induced CSO and CTB, laser RIN and receiver shot noise. Some of these impairments can be filtered out in architectures where a dual-receiver design is implemented in order to receive the narrowcast and broadcast signals separately. Experimental results are shown that illustrate the markedly superior technical performance of dual-receiver designs in accordance with our modeling predictions.