Microwave frequency doubling by synchronising and polarisation multiplexing the optical signals from a dual‐output Mach–Zehnder modulator.

A technique is experimentally demonstrated to double the frequency of a microwave signal by synchronising and polarisation multiplexing the optical signals from a dual‐output Mach–Zehnder modulator. The frequency‐doubled tone at 4 GHz is 41.2 dB stronger than the residual fundamental‐frequency tone. The strongest side tone is found at 12 GHz (sixth order) and is suppressed by 32.7 dB. The phase noise of the frequency‐doubled signal is −104.1 dBc/Hz at an offset of 10 kHz, an increase of 6.7 dB over that of the initial signal. This technique does not rely on electronic or optical filters or amplifiers and is demonstrated using commercial off‐the‐shelf components. [ABSTRACT FROM AUTHOR]