Surface waveguide technology for telecom and biochemical sensing

Abstract

Surface waveguides for telecom applications are typically SiO 2 -based, low-contrast surface waveguides because these applications are dominated by the need for low optical attenuation and low polarization effects across the 1300-1600 nm band. Conventional waveguides, however, comprise films as thick as 20 micron and have minimum bend radii of tens of millimeters. These factors make conventional waveguide circuits large and expensive, and this has limited their use to relatively few applications.In the integrated optical sensing field, the waveguides typically used are (very) high-contrast waveguides. Here, especially Si 3 N 4 -core waveguides are well-known to offer much smaller bending radii (tens to hundreds of microns) due to stronger mode confinement to the core. Since they also typically comprise sub-micron core-thickness and cladding-thickness of only a few microns, high-contrast waveguides promise lower cost than low-contrast waveguides. Their use in telecom applications has been limited, however, due to strong polarization effects. Recently, LioniX, BV has developed the TriPleX™ waveguide, which promises to be a well-suited platform for both telecom and sensing applications and is based on low-cost, CMOS-compatible LPCVD processing. TriPleX™ technology provides highcontrast waveguides with very low channel attenuation and modal birefringence that is controlled through waveguide design alone. Early experiments on typical geometries show promising waveguide characteristics (attenuation « 0.5 dB/cm, IL ≤ -2 dB, PDL « 1 dB, bend radius « 1 mm).In this paper, we present the characteristics of this TriPleX TM technology, and show devices that have demonstrated utility in telecom and/or sensor applications using medium and high-contrast waveguides. Experimental results for an MZI-based sensor platform, suitable for liquid or gaseous sensing, are also provided.

Advances in Mid-Infrared Spectroscopy for Chemical Analysis

“…In contrast to classical trapezoidal or hemispherical ATR waveguide geometries, thin-film waveguides allow single-mode operation, thus leading to significant sensitivity enhancements as the intensity of the radiative energy is efficiently maximized within the evanescent field. This is especially true for slot waveguide designs (87)(88)(89). Slot waveguides transport the entire energy within a narrow slot between the waveguide structures; hence, a nanofluidic sampling gap is inherently provided (89)(90)(91).…”

Broadband optical beam forming for airborne phased array antenna

“…An important parameter in the realization of the optical chips is the loss induced by the waveguide structures. A very promising technology that can meet the high requirements for the optical chip fabrication is the TriPleX technology of LioniX [22], [24], [34], [35]. This technology consists of a multi-layer stack of LPCVD silicon oxide and nitride.…”

Design, fabrication and characterization of a suspended plate mechano-optical modulator

“…In this paper, the design, fabrication and assembly procedure of the suspended plate mechano-optical modulator and its first characterization results are presented. A multi-layer optical waveguide (MLW) technology called TriPleX is used, which was developed by LioniX BV [6,7]. Infra-red light with a wavelength of λ=1550 nm and TE polarization is used for the propagating mode.…”

“…Two distinct cross-sectional geometries are possible with this technology: box shape and A-shape. With both cross sections, the losses due to birefringence, polarization and bending are significantly reduced when compared to conventional and high-index contrast waveguides [6,7]. Figure 3 shows a crosssectional drawing of the A-shape TriPleX waveguide used in this study.…”

“…The TriPleX waveguide is fabricated following the process developed by LioniX as described in [6,7]. The processing is performed on silicon substrates containing 8 μm thick thermal oxide, which acts as the lower cladding of waveguide.…”