Ten-element photodetector for optical power and attenuation measurements

Abstract

The properties of what is, to the best of our knowledge, the first ten-element polarization-dependent transmission trap detector consisting of silicon photodiodes are described. The responsivity and the transmittance of the photodetector were measured at laser wavelengths of 476.2 and 647.1 nm. In particular, the effect of the polarization state of the incident radiation on the transmittance was determined. Differences in transmittance of an order of magnitude were observed between s and p polarization. These values were compared with theoretical values calculated using the Fresnel reflection formulas. The difference between the calculated and measured values was less than +/-3 x 10(-7). The spatial nonuniformity of the response was measured to be less than +/-3 x 10(-4). The transmittance was measured to be spatially uniform across a 5 mm x 5 mm area of the trap detector aperture to within +/-1.5 x 10(-6) for s-polarized input and within +/-1.5 x 10(-7) for p-polarized input.