Compactly integrated polarization insensitive 24-channel variable optical attenuator arrays using silica-based

A 24-channel variable optical attenuator array with a compact size of 15 x 10 mm(2) is demonstrated using silica-based waveguides with 2.0% refractive index difference. Asymmetric Mach-Zehnder structures are well optimized to achieve low polarization-dependent loss (PDL) and wide bandwidth. In addition, the power consumption is reduced by optimizing the trench structures. Experimental results show that the power consumption is 160 mW when the attenuation changes by 10 dB. Within the operating voltage range, the PDL is less than 0.7 dB, and the device can operate in the C+L band with a wavelength-dependent loss (WDL) of less than 0.9 dB.