Tunable Polarization-Dependent-Loss Element Based on Rotatable Birefringent Prisms and a Half-Wave Plate

A novel tunable polarization-dependent-loss (PDL) element is realized using two rotatable birefringent prisms and a half-wave plate. The design is favorable for interferometric stability and is operable over a wide wavelength range. The PDL can be tuned from 0 to 35 dB for a wavelength of 780 nm. An interference visibility of 0.98 between the two principal polarizations for 0-dB loss is achieved by compensating for thickness mismatch between the prisms.