Push-pull modulated analog photonic link with enhanced SFDR

We demonstrate an analog photonic link (APL) with a high multioctave spurious-free dynamic range (SFDR) of 120 dB.Hz
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at the frequency of 2.50 GHz. The APL consists of a pair of distributed-feedback laser diodes (DFB LDs), modulated in a push-pull manner, and a balanced photodetector aiming at suppressing the second-order intermodulation distortion (IMD2). At the frequency of 2.50 GHz, an IMD2 suppression of 40 dB, relative to the case of a single arm APL with one laser, is obtained. In a wide frequency range of 600 MHz (2.60 to 3.20 GHz), an improvement of 5 to 18 dB of the second-order SFDR relative to the single arm APL has been achieved.