OPTICAL POLARIZATION ENCODER

摘要

An optical polarization encoding device (Fig. 1) has been invented which allows wavelength dependent processing of polychromatic optical signals without prior separation into narrow wavelength bands. The invention comprises a stack of variable and fixed birefringent elements (18) which introduces, on passage through the stack (18), a wavelength dependent polarization onto a polychromatic optical signal of arbitrary polarization. Desired polarization are achieved simultaneously at all wavelengths contained within the incoming signal by independently varying the birefringence and/or crystallographic orientation of each element within the stack (18). The encoded signal may be subsequently be processed, e.g. rerouted or attenuated, as a function of wavelength using polarization dependent devices. The encoding stack is rendered polarization insensitive by dividing the incoming signal, with a polarization beam splitter (12), into two beams of orthogonal polarization prior to passage through the stack (18).