Ultrasmall in-plane photonic crystal demultiplexers fabricated with photolithography

We demonstrate ultrasmall demultiplexers based on photolithographic photonic crystals. The footprint of the demultiplexers is 110 μm per channel. Our in-plane demultiplexers are clad with silica, which makes them stable and easy to integrate with other silicon photonic devices. We describe two types of demultiplexers with spacings of 136 and 267 GHz between channels for application to dense wavelength division multiplexing. Integrated titanium nitride heaters allow us to precisely control the channel wavelength. We report a 2.5 Gbps transmittance experiment with sufficiently small crosstalk and discuss ways of achieving even lower crosstalk between channels.