A nanophotonic cladding cloak that prevents crosstalk between two closely spaced single-mode waveguides could allow photonic devices to be integrated at a much higher density, without causing light to leak from one waveguide to another. This would allow billions of photonic devices to be packed into a single photonic computer chip and reduce the footprint of the chip, overcoming a major obstacle to the use of photonic chips in computers, data centers and mobile devices.