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 field-programmable 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.