PHOTOPLETHYSMOGRAPHIC INSTRUMENT HAVING AN INTEGRATED MULTIMODE OPTICAL COUPLER DEVICE

摘要

The integrated multimode optical coupling apparatus comprises an N-to-M optical coupling arrangement that is simple to manufacture, minimizes optical losses and is significantly less expensive than the prior art arrangements of coupling optical signals. The preferred embodiment of the apparatus of the present invention comprises a substrate into which is formed a plurality of optical channels, each of which is joined at one end into a single output optical channel. This integrated optical coupler is formed by diffusing silver ions or other equivalent ions into the glass substrate in these defined areas to form channels of high opticalrefractive index in the body of the substrate. At one end of each of the opticalchannels that are formed in the substrate, the plurality of the optical channels are joined together in a volumetric region of the substrate wherein the individual channels merge into one unified common structure. The output optical channels are joined to this combiner to thereby carry the combined light output to the output terminals. One application of this apparatus is in the field of photoplethysmography, such as in a pulse oximeter instrument.