Compact two-element transmission trap detector for 1550 nm wavelength

Abstract

We have developed and characterized a new kind of trap detector based on InGaAs photodiodes. The detector contains only two 10 mm diameter InGaAs photodiodes arranged in a transmission trap configuration with non-coaxial beam orientation. The detector has large active area, more than 9 mm in diameter, and a built-in linearity monitoring feature. One of the key advantages of the developed detector is polarization insensitivity-the difference in responsivity between two orthogonal incident polarization states is zero within the standard uncertainty of 0.3%. The spatial non-uniformity of the responsivity is less than 0.5% across the active area.

Metrology for industrial quantum communications: the MIQC project

“…The attenuator provides a free space attenuation of 3.6 × 10 −5 with k = 2 uncertainty of 4.4% at the wavelength of 1550 nm. The attenuation was directly measured to be independent of incident power over the range of 10 nW up to 1 mW [12]. While the transmission trap detector is used as a fibre coupled attenuator, as described above, the uncertainty at k = 2 level for total attenuation is 3%.…”