SOA waveguide modulators have a 90% loss due to the mismatch between the fiber-waveguide interface. Previous efforts in industry to reduce this loss, although successful, have suffered from low yield due to the complex processes used. None of these devices are available commercially since they are not manufacturable. The proposed effort will develop a technique which can be precisely controlled and repeated using the Vytran. A literature search has not found any references of others using the device for this application. The low loss waveguide modulator proposed will enable further miniaturization of the current fNIRS system, achieving the next step in developing a compact, wearable device. Currently no commercial product exists to measure cognitive state in the field, work in this area has been experimental using rack mounted equipment in a lab environment. The FY17 GRC effort reduced the rack of commercial hardware into a 7”x23”x17” box with associated headgear. Further development of a wearable crew state monitor would enable an innovative early warning system during long duration missions, with both space and aeronautics applications. Spaceflight applications include detecting and preventing vigilance decrements due to the effects of microgravity: motion sickness, lack of sleep, loss of sensorimotor control, increased stress or mood changes. Commercial applications include avoiding mistakes by pilots and other safety critical personnel such as air traffic controllers when faced with stressors that compromise cognitive ability such as fatigue, noise, heat, vibration, and mental workload.