Opt. Lett. 39, 1046–1048 (2014)

Credit: © 2014 OSA

Supercontinuua are broadband spectra of coherent light that are generated by nonlinear optical processes. Such radiation is useful for applications in imaging, metrology and optical communications. It is usually generated in a length of photonic crystal fibre that has been engineered to possess a large nonlinearity. However, it is desirable to realize sources that are more compact and integrated. Now, Dong Yoon Oh and co-workers from California Institute of Technology and the National Institute of Standards and Technology in the USA report supercontinuum generation from spiral glass waveguides on a chip. Their design consists of a series of four connected silica Archimedean spiral waveguides with a total path length of 3.5 m. Each spiral has an outer radius of 7 mm, and the chip measures 2.5 cm × 6.9 cm. When ultrashort (180 fs) pulses of infrared radiation (wavelength, 1,330 nm) from an optical parametric oscillator were launched into the chip, a broad spectrum spanning 936–1,888 nm was measured. The team says that with further refinement the approach could become a viable platform for performing various nonlinear optics tasks on a chip.