Cascadability of large-scale 3-D MEMS-based low-loss photonic cross-connects

The performance of cascaded low-loss (<3.5 dB) 256×256 three-dimensional microelectromechanical system (3-D MEMS) photonic cross-connects (PXCs) is experimentally investigated in a recirculating loop. After 60 transitions through the PXC, a power penalty of 1.7 dB is observed, which is attributed to the accumulation of the low polarization-dependent loss in the optical switch. The use of 3-D MEMS PXCs as a wavelength-selective switch (WSPXC) for transparent all-optical networks is also demonstrated. Measured Q-factors for all 16 100-GHz-spaced wavelengths at 10 Gb/s over eight spans of 75-km single-mode fiber and eight transitions through the WSPXC nodes are better than 17 dB.