Intermodulation distortion suppression for intensity-modulated analog fiber-optic link incorporating optical carrier band processing.

An intermodulation distortion suppression method based on the optical carrier band processing is demonstrated. A systematic analysis of the main optical spectrum contributors for the third-order intermodulation distortion in the nonlinear system is presented. Theoretical analysis shows that the third-order intermodulation distortion terms can cancel each other if a proper phase shifting is imposed to the optical carrier band. We experimentally demonstrate the approach with a two-tone test and a suppression of about 33 dB in the third-order intermodulation distortion is obtained. Experimental results show that an overall fundamental to third-order intermodulation distortion ratio of up to 64 dB is achieved and the link dynamic range is improved by 14.7 dB, compared with the conventional link without the proposed optical carrier band processing.