  Multi-antenna radio front-ends generate a multi-dimensional flood of
information, most of which is partially redundant. Redundancy is eliminated by
dimensionality reduction, but contemporary digital processing techniques face
harsh fundamental tradeoffs when implementing this class of functions. These
tradeoffs can be broken in the analog domain, in which the performance of
optical technologies greatly exceeds that of electronic counterparts. Here, we
present concepts, methods, and a first demonstration of multivariate photonics:
a combination of integrated photonic hardware, analog dimensionality reduction,
and blind algorithmic techniques. We experimentally demonstrate 2-channel, 1.0
GHz principal component analysis in a photonic weight bank using recently
proposed algorithms for synthesizing the multivariate properties of signals to
which the receiver is blind. Novel methods are introduced for controlling
blindness conditions in a laboratory context. This work provides a foundation
for further research in multivariate photonic information processing, which is
poised to play a role in future generations of wireless technology.
