Design and Construction of an Affordable Optical Power Meter: Micro- to Milli-Watt in the 400-800 nm Range

This study introduces the design, construction, and evaluation of an affordable optical power meter prototype, AYR (Affordable Yet Reliable) version 1.0, which operates effectively within the 400-800 nm range, using a silicon photodiode. Aimed at bridging the gap in accessibility to precise and reliable photonics instrumentation, especially in resource-constrained settings, AYR 1.0 leverages advancements in photodiode technology, additive manufacturing, and do-it-yourself electronics. The device incorporates a custom-built electronic circuit that facilitates accurate optical power measurement by converting light into electrical current. Through rigorous testing against a reliable commercial optical power meter, AYR 1.0 demonstrated exceptional accuracy and reliability. Sensitivity values ranged from ~13 µA/mW at 405 nm to ~796 µA/mW at 805 nm. The operational power range spanned from 0.003 mW to 242.0 mW, with linearity (R²) values consistently above 0.9981, indicating high fidelity in measurement. Repeatability percentages varied between 99.4% and 99.9%, and response times ranged up to 55 µs, showcasing the prototype's rapid and reliable response to changes in optical power. The key components include a low-cost silicon photodiode (2DU10), a differential trans-impedance amplifier circuit for signal processing, and a 3D-printed housing for the sensor head and console, contributing to its cost-effectiveness and robustness. The prototype's total cost was 116 US dollars, highlighting its affordability and potential for widespread adoption.