A flattop PLC polymer waveguide interleaver based on folded two-stage-cascaded Y-junction Mach–Zehnder interferometers

We demonstrate realization of a flattop Y-Junction Planar Optical Waveguide Interleaver (YJPOWI) with a channel spacing of 100 GHz through a novel scheme of folded cascaded two-stage unbalanced Mach–Zehnder interferometers (MZI) fabricated on a polymer Planar Lightwave Circuit (PLC) platform. The characteristic 0.5 dB passbands of the interleaver centered at ITU wavelength grids at its two output ports were 50 and 45 GHz, respectively. The operating bandwidth of the device spanned the entire C band of a fiber amplifier and it is compact in size (1.3 × 1.4 cm2). In addition, the device is easy to fabricate and do not require any individual heater to trim its performance.