Diffractive optics development using a modified stack-and-draw technique

Pniewski J., Kasztelanic R., Nowosielski J.M., Filipkowski A., Piechal B., Waddie A.J., Pysz D., Kujawa I., Stepien R., Taghizadeh M.R. and Buczynski R.

Applied Optics

55 (18), 2016, 4939-4945, 10.1364/AO.55.004939

We present a novel method for the development of diffractive optical elements (DOEs). Unlike standard surface relief DOEs, the phase shift is introduced through a refractive index variation achieved by using different types of glass. For the fabrication of DOEs we use a modified stack-and-draw technique, originally developed for the fabrication of photonic crystal fibers, resulting in a completely flat element that is easy to integrate with other optical components. A proof-of-concept demonstration of the method is presented—a two-dimensional binary optical phase grating in the form of a square chessboard with a pixel size of 5 μm. Two types of glass are used: low refractive index silicate glass NC21 and high refractive index lead-silicate glass F2. The measured diffraction characteristics of the fabricated component are presented and it is shown numerically and experimentally that such a DOE can be used as a fiber interconnector that couples light from a small-core fiber into the several cores of a multicore fiber.