Apparatus and methods for upconversion of a millimeter-wave signal and detection of the upconverted signal

A millimeter-wave receiver apparatus comprising:

• (a) a continuous-wave upconverting laser source arranged so as to produce a linearly polarized upconverting optical signal characterized by an upconverting optical frequency νOPT;
• (b) an input beam combiner that is positioned and arranged so as to combine the upconverting optical signal and a propagating input signal, each incident on the input beam combiner, to copropagate away from the input beam combiner, the input signal being (i) characterized by a gigahertz input signal frequency νGHz and (ii) modulated to encode transmitted information
• (c) a nonlinear optical medium positioned and arranged so that the combined upconverting optical signal and input signal copropagate through the nonlinear optical medium and generate therein one or more upconverted optical signals, at one or both sum or difference frequencies νSUM=νOPT+νGHz or νDIFF=νOPT−νGHz, that copropagate with the upconverting optical signal and are linearly polarized substantially orthogonal to polarization of the upconverting optical signal;
• (d) a linear polarizer positioned and arranged so as to separate (i) propagation of the upconverting optical signal from (ii) propagation of the one or more upconverted optical signals;
• (e) a spectrally selective optical filter positioned and arranged so as to preferentially transmit at least one of the separated upconverted optical signals relative to transmission of a copropagating, residual portion of the upconverting optical signal that is linearly polarized substantially parallel to polarization of the upconverted optical signal;
• and
• (f) a detection system that includes one or more photodetectors and is positioned and arranged so as to (i) receive the upconverted optical signal transmitted by the optical filter and (ii) generate therefrom one or more electrical output signals that include at least portions thereof that are modulated to encode at least portions of the transmitted information.