Fabrication and optical characterization of sub-micronic waveguide structures on UV210 polymer

Abstract

In this paper, we report on the interest in a new polymer, UV210, in the field of integrated optics. As 400 nm wide and 1 µm high UV210 rib waveguides have been obtained by deep ultraviolet (DUV) lithography and controlled by scanning electron micrographs (SEMs), they allow us to realize sub-wavelength structures by way of easy and cheap processes. Structural and optical investigations have been carried out on UV210 resist as a function of exposure to DUV light. On the one hand, structural properties through ellipsometric measurements have been investigated: the UV210 refractive index increases with the DUV exposure dose, yielding a large index contrast at 980 nm between areas exposed or not (Δn = 2 × 10 − 2). It is expected that we shall soon be able to photo-print nanometric patterns onto UV210 films. On the other hand, optical studies of propagation losses measured in both irradiated and unexposed single-mode UV210 waveguides have been performed by a cut-back method. Concerning as-deposited rib waveguides, optical losses for TE00 and TM00 optical modes have been evaluated to 3.4 ± 0.4 dB cm − 1 and 6.2 ± 0.5 dB cm − 1, respectively. Hence, the UV210 polymer appears to be a promising candidate for the development of low-cost nanometric structures for miniaturized optical chips, with numerous applications in telecommunication and sensor technology.

A laterally coupled UV210 polymer racetrack micro-resonator for thermal tunability and glucose sensing capability

“…These results highlight the mean values of four ascending and descending measurements with intervals of 5 min between each point for stability on the signal. By taking into account the refractive index for TE mode n UV210 ¼ 1.556 and the assessed thermal sensitivity, the thermo-optic coefficient of the UV210 photoresist is calculated as Dn/DT< 2 2.3 £ 10 24 8C 21 , which is in good agreement with known values for polymers. 11,28,29 Additionally, the blue-shift thermal tunability of the optical racetrack microresonator is demonstrated by varying the top cladding conditions.…”

“…5b for this polymeric UV210 racetrack microresonator with a rate of thermal sensitivity averaging 220^11.6 pm 8C 21 . Nevertheless, a slight tendency to saturate the thermo-optic response is observed when the temperature is increased above 308C.…”

“…11,18 -20 In this work, we present the viability of a specific microresonator, based on a racetrack shape and on UV210 photoresist, as a temperature and glucose sensor. Recently, UV210 photoresist has been used as single mode rib waveguides 21 and submicrometer 2D-resonators 15 demonstrating the high capability of the polymer for photonic miniaturization. Then, the design and the overall fabrication and optical characterization of a cascade of multiple microresonators acting as modal filters have been presented.…”

“…As regards the lower limit of detection of such sensors devoted to low glucose detection concentrations ranging between [0 and1] mg ml 21 , for typical glucose concentration values considered within human cells, we manage to detected a lower limit concentration down to 0.04 mg ml 21 corresponding to a relative change about 10 25 on the value of the optical refractive index of the glucose solution. Such experimental data demonstrate the capability of this OI device based on UV210 photoresist to achieve homogeneous biorecognition measurements: moreover, its linear sensitivity is in the same order as that of published performances of polymeric microresonators for glucose homogeneous sensing.…”

Fabrication and optical characterization of pedestal micro-structures on DUV210 polymer: waveguides structures towards micro-resonators

“…They also offer many possibilities in designing techniques, leading to very different geometries [8,9]. The polymer used in this paper is the DUV210, particularly interesting because of its tunable refractive index by controlling the exposure time [10]. The devices presented here are prepared by deep UV lithography [11].…”