Melanie Holmes

Holographic optical switching: the "ROSES" demonstrator

The design, assembly, and performance of a prototype 1/spl times/8 free-space switch demonstrator using reconfigurable holograms are reported. Central to the switch fabric is a ferroelectric liquid crystal (FLC) on silicon spatial light modulator (SLM) deposited with a 540/spl times/1 array of highly reflective and planar mirror strips. The input and output ports of the switch are fabricated as a linear array of silica planar waveguides connected to single-mode fibers, and the holographic beam-steerer operates without the need for adjustment or dynamic alignment. The waveguide array and the single Fourier transform lens for the 2f holographic replay system are housed in an opto-mechanical mount to provide stability. The switch operates at 1.55 /spl mu/m wavelength and has a designed optical bandwidth of >60 nm. The first measured insertion loss and crosstalk figures are 16.9 dB and -19.1 dB, respectively. Improvements in SLM performance, the use of new addressing schemes and the introduction of better alignment techniques are expected to improve these figures considerably. The preliminary performance of a 3/spl times/3 optical crossconnect is also presented to show that this technology is scalable to N/spl times/N switching fabrics.

Liquid crystal polarization independent beam steering switches for operation at 1.5 microns

The rapidly evolving demands of telecommunications systems have created a new market for high capacity all-optical photonic switches. Holographic optical switching may offer a scalable and reliable approach to realizing such systems. The advantages and technical challenges associated with this technology will be discussed, with reference to two prototype demonstrators recently produced under the auspices of the ROSES project. The first is a single beam deflector operating as a 1/spl times/8 switch and the second is a 3/spl times/3 optical switch which demonstrates the principle of crossbar operation.