Improved accuracy of a Fourier-domain optical processor with feedback

The ability to shape the spectral amplitude and phase of optical signals is a key requirement in the fields of optical arbitrary waveform generation (O-AWG) and optical communications. To this end much effort has been directed towards developing programmable Fourier-domain optical processors (FDOP) capable of adjusting the amplitude and phase of the individual spectral components of an input optical signal. In practice these FDOP devices can suffer from a number of imperfections in their amplitude and phase transfer functions resulting from: imperfect calibration, wavelength dependence of the FDOP, and even in some circumstances a coupling between the programmed phase and amplitude transfer functions. In this paper we demonstrate a simple feedback loop capable of correcting for all of the above impairments.