  A content addressable memory (CAM) is a type of memory that implements a
parallel search engine at its core. A CAM takes as an input a value and outputs
the address where this value is stored in case of a match. CAMs are used in a
wide range of applications including networking, cashing, neuromorphic
associative memories, multimedia, and data analytics. Here, we introduce a
novel opto-electronic CAM (OE-CAM) utilizing the integrated silicon photonic
platform. In our approach, we explore the performance of an experimental OE-CAM
and verify the efficiency of the device at 25Gbit/s while maintaining the bit
integrity under noise conditions. We show that OE-CAM enables a) two orders of
magnitude faster search functionality resulting in b) a five orders of
magnitude lower power-delay-product compared to CAMs implementations based on
other emerging technologies. This remarkable performance potential is achieved
by utilizing i) a high parallelism of wavelength-division-multiplexing in the
optical domain, combined with ii) 10s of GHz-fast opto-electronic components,
packaged in iii) integrated photonics for 10-100s ps-short communication
delays. We further verify the upper optical input power limit of this OE-CAM to
be given by parasitic nonlinearities inside the silicon waveguides, and the
minimal detectable optical power at the back-end photoreceivers responsivity
given channel noise. Such energy-efficient and short-delay OE-CAMs could become
a key component of functional photonic-augmented ASICS, co-processors, or smart
sensors.
