This paper presents a safe, affordable, and noninvasive approach to estimate subcutaneous fat thickness by using a multi-distance
near infrared (MD-NIR) interactance-based wireless sensing platform. In order to perform the simultaneous
measurements at several distances, two light sources with different wavelengths are located at one end of a line followed
by seven photo diodes. Bluetooth Low Energy are adopted as their primary communication protocol as a wireless
communication. The measured data from the MD-NIR interactance sensors are wirelessly transmitted to a smartphone or
a tablet for analysis. The feasibility of the approach and wireless platform is demonstrated using the ex vivo pig fat layer
Many biomedical applications require an efficient combination and localization of multiple discrete light sources. In this paper, we present a compact six-channel combiner of optical sub-assembly type that couples the output of independent solid-state light sources into a single 400 μm diameter optical fiber. It is equipped with six discrete laser diodes, 658, 690, 705, 785, 830, and 850 nm for the measurement of the tissue optical properties from optical spectroscopy and imaging. We demonstrate coupling efficiencies ≥ 77% and output optical power ≥ 20 mW for each of the 6 laser diodes installed into the prototype. The design supports the use of continuous wave and intensity modulated laser diodes (with bandwidth ≥ 3 GHz). The developed light source could be used to construct custom multi-wavelength sources for tissue oximeters, diffuse optical imaging, and molecular imaging technologies.