[Tom_Monaghan1991]

Hi guys,

I've recently been reading around the area of on-chip reaction monitoring in microfluidic devices and a common question keeps popping up in my mind that I was hoping someone could shed some light on.

During the fabrication of the fluidic chip, the authors typically state that waveguides are incorporated parallel to the flow channel, and then coupled to an external optical fibre. These waves guides are usually something like a square section Silicon.

My question is, does anyone know why its often chosen to form a waveguide in the device and incur a variety of potential light power losses as opposed to inserting the optical fibre directly into the channel via the incorporation of grooves/slots in the substrate?

My initial thoughts were based on the aspect ratios and shapes it is possible to form during the various manufacturing processes for fluidic devices resulting in a poor seal with the fibre that could potentially lead to a device with low pressure tolerance. The second common theme I found was that accurate alignment of the waveguides is possible.

If anyone else has any experience in this area or has any other reasons why optical wave guides are used as opposed to direct fiber insertion any info would be great!

Regards

Tom

[curiouscat]

I am clueless but since this sounds very interesting can you provide a link to a detailed description of these setups?

[Tom_Monaghan1991]

Of course, here are a few papers which have detailed descriptions;

http://www.sciencedirect.com/science/article/pii/S0924424706006030

http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-15-5-2307

http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=5290403

Hope these help, its not any easy thing to try and explain in words. The simple schematics in the papers illustrate it perfectly however