Integration of microfluidics with grating coupled silicon photonic sensors by one-step combined photopatterning and molding of OSTE

Abstract

We present a novel integration method for packaging silicon photonic sensors with polymer microfluidics, designed to be suitable for wafer-level production methods. The method addresses the previously unmet manufacturing challenges of matching the microfluidic footprint area to that of the photonics, and of robust bonding of microfluidic layers to biofunctionalized surfaces. We demonstrate the fabrication, in a single step, of a microfluidic layer in the recently introduced OSTE polymer, and the subsequent unassisted dry bonding of the microfluidic layer to a grating coupled silicon photonic ring resonator sensor chip. The microfluidic layer features photopatterned through holes (vias) for optical fiber probing and fluid connections, as well as molded microchannels and tube connectors, and is manufactured and subsequently bonded to a silicon sensor chip in less than 10 minutes. Combining this new microfluidic packaging method with photonic waveguide surface gratings for light coupling allows matching the size scale of microfluidics to that of current silicon photonic biosensors. To demonstrate the new method, we performed successful refractive index measurements of liquid ethanol and methanol samples, using the fabricated device. The minimum required sample volume for refractive index measurement is below one nanoliter.

Edge Couplers in Silicon Photonic Integrated Circuits: A Review

“…In the meantime, these designs usually bring increased coupling loss. When it comes to edge couplers, despite the apparent advantages such as high coupling efficiency, broad bandwidth, and low dependence on polarization, the main limits lie in that edge coupling only allows the alignment of fiber with the coupler at the chip facet, which is less convenient compared with grating couplers that support wafer-level testing at different positions on the wafer plane [116][117][118]. Meanwhile, edge couplers generally have larger footprints in the longitudinal dimension.…”

LeTrungThanh Optical Biosensors Based on Multimode Interference and Microring Resonator Structures

“…This leads to large footprint area and low sensitivity. For example, recent results on using single microring resonators for glucose and ethanol detection showed that sensitivity of 108nm/RIU [2,15], 200nm/RIU [16] or using microfluidics with grating for ethanol sensor with a sensitivity of 50nm/RIU [17]. Silicon waveguide based sensors has attracted much attention for realizing ultra-compact and cheap optical sensors.…”

Two-channel highly sensitive sensors based on 4 × 4 multimode interference couplers

“…For example, recent results showed that the sensitivities of 108 nm/RIU [2,12] and 200 nm/RIU [13] for glucose and ethanol detection using single microring resonator can be achieved. In addition, by using microfluidics with grating, ethanol sensor with a sensitivity of 50 nm/RIU can be obtained [14]. The silicon waveguide based sensors have attracted much attention for realizing ultra-compact and cheap optical sensors.…”