Beam steering optical switches using LCOS: the 'ROSES' demonstrator

The design, assembly and results of a 1.8 free-space switch demonstration using dynamic 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 to the switch are fabricated as a linear array of silica planar waveguides connected to single-mode fibres. The waveguide array and the single Fourier transform lens for the 2f holographic replay system are housed in an optomechanical 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. Significant improvements in these figures can be expected.