Photonic biosensors for medical diagnostics have been in development for some time. They have proven to show equal or better performance as compared to other techniques in terms of sensitivity, accuracy, and reliability. In order for companies to successfully introduce these sensor products on the market, they must also perform equal or better in price per test and usability.
The price per test is to a large extent determined by the costs of the (disposable) cartridge containing the sensor chip and bioactive layer. If the active components can be left out of the cartridge a significant cost reduction can be obtained. However, this adds the challenge of coupling light from the source to the sensor chip inside the cartridge and back onto detectors.
This coupling requires a positioning accuracy in the (sub-) micrometer regime. Here, we present a demonstrator system, which implements an passive alignment step followed by an active alignment procedure. The initial alignment is realized with high accuracy when placing a cartridge in an acceptor slot. This results in finding a “first light” state, which allows the active alignment to take over. Active alignment is then realized by moving the fiber by means of a set of actuators to the position with optimal coupling efficiency.
A demonstrator was designed and manufactured to test the influence of several key parameters, such as the influence of production accuracy of the cartridges on the initial alignment. The resulting system has shown to comply with the requirements of ease of alignment along with full automation.