Abstract:

Electroholography is a wavelength-selective optical switching method based on governing of the reconstruction process of volume holograms by means of an electric field. Electroholography is based on the voltage-controlled photorefractive effect in the paraelectric phase. The basic switching device is an electrically controlled Bragg grating or a volume hologram stored in a volume of a paraelectric crystal by the photorefractive process. The basic electroholographic switching operation is the reconstruction of a volume grating (hologram), which requires that the Bragg condition be satisfied, and therefore is wavelength selective. In addition the applied field governs the efficiency of the reconstruction. Consequently, electroholographic switching includes grouping, multicasting, power management and non-intrusive data as an integral part of the switching operation. In preliminary measurements the performance envelope of the electroholography-based switch, is a cube of 1.8 mm3 was found to be as follows: The minimum net insertion loss is 0.5 dB per switching operation. The minimum loss when a beam propagates through a latent grating is 0.2%. The Polarization-Dependent Loss (PDL) in a device that includes diversity architecture is less than 0.4 dB and the Polarization Mode Dispersion (PMD) is less than 0.07 ps. Bit-error rate (BER) in a switch operating at 40 Gb/s was measured to be 10-13. These features make electroholography ideal for circuit switching applications. Finally, response times of approximately 10 ns were measured, opening the way to burst switching applications.