Photonic Add-Drop-Gate Node Element Based on EML Technology

We propose a novel approach for reconfigurable
photonic nodes in short-reach optical networks, which builds on
unified component technology for several key functions. The need
for fast transmission, reception and switching components is
addressed through use of a widely adopted technology that is
particularly known for its cost efficiency: the externally
modulated laser (EML). Through consequent use of EMLs as fast
and versatile electro-optic node element in combination with a
slower yet reconfigurable cross-connect matrix serving as
interconnection between several elements, a node architecture
can be synthesized on demand – such as known from fieldprogrammable
gate arrays that have revolutionized the field of
programmable microelectronics.
To prove the proposed multi-functional EML-based approach,
we experimentally investigate the capabilities of this photonic
transmitter as coherent receiver of dropped signals and as optical
gate, being the basic element of fast switches. We first
demonstrate the polarization-immune coherent homodyne
reception of broadband 10 Gb/s on-off keyed signals without
further need for digital signal processing. Transmission is shown
at an optical budget of 24 dB and in presence of 12 side-channels.
Moreover, the EML is applied as fast 1×1 switch by proving that
gating at the sub-ns regime can be facilitated at a reception
penalty of less than 1 dB.