US Patent 7155082 Switchable microfluidic optical waveguides

The present invention provides microfluidic optical waveguides and waveguide switches providing capability for multiple outlet paths for the fluid waveguides and optical signals contained therein. A microfluidic structure comprises a core inlet channel, one or more cladding fluid inlet channels intersecting with the core inlet channel downstream of a core inlet, and at least two outlet channels coupled to the core inlet channel and downstream of the cladding fluid channel. An optical source providing an optical signal is aligned with the core inlet channel. A waveguiding fluid is supplied to the core inlet channel and a cladding fluid supplied to each of the cladding channels. The waveguiding fluid and cladding fluid form an optical waveguide operable to transmit the optical signal. The flow rate of the cladding fluid is selectable to switch the optical waveguide between at least the first and second outlet channels.