We present a compact design for an integrated interconnect based on a hybrid imaging setup combining microchannel and conventional imaging. Within this setup the conventional imaging is performed by an aluminum-coated spherical lens. The aberrations introduced by this spherical mirror to the channels of the interconnect can be compensated by channel-wise adapted microlenses located at the in- and output interfaces. These microlenses are used for collimating or refocusing the beams, respectively. Within this paper we present the design of the microlens array with individually shaped lenses referred to as chirped mircolens array (cMLA) based on numerical optimization and the use of fitting functions. Further on we focus on the fabrication of the chirped microlens arrays by laser lithography and first experimental results of coupling efficiencies of singlemode as well as multimode fibers for the realized prototypes.
Conventional microlens arrays consist of a repetitive arrangement of a unit cell on a fixed pitch. In a chirped array, the inflexibility of a regular structure has been overcome. Here, the array consists of individually shaped lenses which are defined by a parametric description of the cells optical function. We propose different fabrication methods for chirped microlens arrays and present experimentally obtained data. Reflow of photoresist is an established technology for the fabrication of microlenses with superior optical performance. For the generation of a chirped microlens array the photolithographic mask for patterning the resist to be melted has to be chirped. We present an algorithm for mask generation with an example of an ultra-thin camera objective. Inherent to the reflow process stringent limitations to viable surfaces apply. For achieving more arbitrary surfaces, laser lithography and also 2-photon polymerization are employed. In both methods the structures are decomposed into pixels. In laser lithography the local height is converted into an intensity value for the exposure. This variable dose writing locally changes the solubility of the resist in the development process leading to the required surface profile. We propose a writing scheme enabling structure heights of several ten microns with sufficient height discretization. 2-photon polymerization is a rapid prototyping method. Here, a small volume of a UV-curing organic-inorganic co-polymer is hardened in the tight focus of the writing beam. The volume pixel to be exposed is addressed by piezoelectric translation stages. Experimentally obtained structures and performed tests of the optical quality are presented
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.