ΦPU – A Photonic Processing Unit for Heterogeneous Optical Networks

Digital signal processing (DSP) has become a
cornerstone of optical signal transmission. Today, a plethora of
tasks inherent to a wide range of optical communication systems
are being transferred to the digital domain to perform signal
shaping, modulation and recovery. At the same time, opticallayer
subsystems are kept as lean as possible, even though they
are recognized for their ample bandwidth and high degree of
energy efficiency. Towards exploring these gains, we propose and
experimentally demonstrate the concept of a multi-functional
photonic processing node that is tasked to decode partialresponse
formats, to demodulate multi-level signals, to generate
high-frequency radio signal carriers, to cancel crosstalk in fullduplex
transmission schemes involving non-orthogonal
modulation formats, and to perform neuromorphic signal
processing. As we will demonstrate, all these tasks can be
accomplished with a rather small set of photonic toolbox
elements dedicated to an efficient electro-optic frequency
translation and spectral signal manipulation. We prove that the
majority of the aforementioned functions can be executed with
superior performance when compared to DSP-based methods
and with great potential for energy- and footprint-efficiency.