Benefits of a Scaled Differential Calculation method for use in a Fabry-Perot based Optical Cavity Biosensor

摘要

To lower the overall cost of an optical cavity biosensor, while still taking advantages of highly sensitive Fabry-Perot based optical cavity structures, we have proposed the use of two low cost, off-the-shelf laser diodes and employ a scaled differential calculation method instead of monitoring the intensity changes of a single laser diode. This paper describes three of the benefits of using the scaled differential calculation: enhanced responsivity, power equalization, and an increased fabrication tolerance. Over the same change in sensing layer thickness, the scaled differential value changes three times as much as a single laser. If the starting value of an efficiency curve changes, it will drastically change the results of a single laser measurement. Changes in the starting value of the efficiency do not affect the scaled differential calculation. With the use of the scaled differential calculation, there is a large fabrication tolerance, allowing for cheaper production.