  Digital signal processing (DSP) is supporting novel in-field applications of
optical interferometry, such as in laser ranging and distributed acoustic
sensing. While the highest performances are achieved with field-programmable
gated arrays (FPGAs), their complexity and cost are often too high for many
tasks. Here, we describe an alternative solution for processing optical signals
in real-time, based on a dual-core 32-bit microcontroller. We implemented
in-phase and quadrature (IQ) demodulation of optical beat-notes resulting from
the interference of independent laser sources, phase noise analysis of deployed
optical fibers covering intercity distances, and synchronization of remote
acquisitions via optical trigger signals. The embedded architecture can
efficiently accomplish a large variety of tasks in the context of optical
signal processing, being also easily configurable, compact, and upgradable.
These features make it attractive for applications that require long-term,
remotely operated, and field-deployed instrumentation.
