Because of the mixing of multiple reflections in both spheres, variations in power measurement due to fiber placement are minimized. This means the repeatability of the measurement has increased as well. Since there is no path for a light ray to pass from input port to output port without at least two reflections, variation in measurements due to polarization state also is reduced. Since multiple detectors may be mounted to the second chamber, polarization dependency may be further reduced or, with the addition of filters before the detectors, a simple method to measure wavelength is possible.
This article was written by Scott Remington, applications engineer at ILX Lightwave Corporation. For information, call (800) 459- 9459 or visit http://info.ims.ca/5292-230.