Abstract: A wavelength-selective filter, such as a narrow bandpass filter, is used to filter both the input and output of an optical amplifier. The selected channel is amplified and can be re-combined with the other original channels or provided to another output, depending on amplifier configuration. In a particular embodiment, a two-stage amplifier with center stage access uses a single gain-flattening filter to compensate for gain tilt of both amplifier stages.

Abstract: A transparent strain sensitive surface is disclosed which is suitable for strain gages, video terminal touch panels, security panels (windows, display cases, etc.). The strain gage includes a transparent, strain sensitive conductor of indium tin oxide (ITO) or indium oxide (IO) on a transparent substrate. The strain sensitive panels include a crossed xy matrix of transparent IO or ITO strain sensitive conductors formed on the same side or on opposite sides of a transparent substrate.

Abstract: Force transducing load cell having a load arm, a load bearing beam rigidly connected to the load arm for bending in response to a load applied to the arm, strain sensing elements mounted on the beam for providing an output signal corresponding to a load, and restraining arms which permit axial movement of the load arm and direct extraneous forces produced by off-center or non-axial loading away from the beam. The beam is bent in a double curved, S-shaped manner with separate regions of tensive and compressive stress on one surface, and the sensing elements are mounted in these regions to effect cancellation of any extraneous stresses produced in the beam by off-center loading.