Linear dual electroabsorption modulator for analog optical transmission

An all-optical linearization technique is proposed for electroabsorption optical modulators (EAM). The scheme provides a relatively simple process of linearization by adding a sub-EAM. By including the sub-EAM with different lengths, DC bias, and bandgap wavelengths, the nonlinear components of the main EAM were optically compensated. The third order intermodulation products produced by the nonlinear transfer curve of the main modulator were reduced by as much as 30 dB. Through the suppression of the third-order intermodulation products, subsequent enhancement of a suboctave spurious free dynamic range of about 20 dB was achieved.