Multichannel Intermodulation Distortion in High-Speed InGaAsP Lasers.

We present an experimental study of intermodulation distortion (IMD) in high-speed, long wavelength InGaAsP lasers modulated up to 8 GHz. It is found that three-tone distortion products are the dominant contribution to IMD interference when the number of subcarriers is large. This distortion data is used with a simple theory to accurately predict the measured signal- to-noise ratio for each channel of a multichannel subcarrier system.