OIL’s Sensor Concept #1 for stacked PWG combiner/splitter units using separate linear arrangements of VCSEL’s and PD’s: One sensor concept was explored and developed for a customer’s application to sense optical fiber accessed sites for remote sensing or fiber continuity. The 12 fiber channelunit is depicted in the photo. An illustration of the waveguide and coupling interfaces is shown. Alos the top view of the actual delivered parts for the waveguide coupling and fiber array interface is shown as well. Details will be reviewed in ref 10. The twelve 2 to 1 stack is aligned by laser micro machined alignment plates with slots that hold the precisely machined combiner/splitter units vertically. This sensor core can be utilized for broad range of sensing as well as fiber ribbon doublers not shown here. The array of 12 fibers is also aligned and held by alignment plates. On the upper right is an alignment plate for a 12 unit array of VCSELs and PD’s or alternatively for optical fibers connected to the lasers and PD’s. The signals propagate through the combiner to the fibers and to some remote region for sensing. The expected modified return signal travels back to the PWG operating as a splitter with each channel monitored by the respective PD.
OIL’s Sensor Concept #2 for planar PWG combiner/splitter PWG array using a linear array of alternating VCSELs and PDs sensor. A second sensor concept is easier to assemble but not as compact as the first described in the previous photo. It uses a single PWG film unit as an imaged combiner/splitter. Alternating input and output are configured using optical fibers. The combiner/splitter unit can also be separate from a disposable or reusable sensing head region as is shown in the photo. In this case the sensing head region was an array of PWG’s that started with 500 micron center to center spacing and contracted to an array with 60 micron center to center spacing as depicted and will be detailed in ref 10 elsewhere. The output sensing head face is shown for 8 nominally 50 micron square waveguides. This sensing unit could be used for capillary monitoring etc. However, for this customer’s specific in-vivo bio-sensing application the sensing array was inserted into a needle and then into the sub cutaneous skin layer for monitoring a body fluid constituent using special design not discussed. OIL’s sensor head system reduced to practice the startups customer’s concept for continuous monitoring of specific (confidential) body fluid constituent monitoring for patients with critical needs.
OIL’s Sensor Concept #3 for intersecting waveguides at a sensing surface: As depicted in the photo two intersecting waveguides are shown that have defining barriers imaged during waveguide exposure that allow light to be guided to the sensing surface. Here the waveguide propagated light reflects or scatters off the media at the interface and returns in the second waveguide. The guiding structures within the intersecting waveguides keep the light within each waveguide for input and output. The guiding structures are a low index region 4 microns wide that spans through the waveguide top to bottom. It permits light to be guided within the input and output waveguides. These low index barriers are identical to the structures imaged inside our waveguides that deflect light to higher angles as mode scramblers discussed separately. See Capability section below for more details. For the application depicted in the photo OIL’s unique waveguide sensor configuration was combined with proprietary carbon nanotube technology from Pettit Applied Technologies to create an optical signal proportional to an applied voltage. This technology was developed for the Air Force Fly-By-Light program.