Modal noise investigation in multimode polymer waveguides

In this work the recent interest in waveguides for use in short optical links has motivated a study of the modal noise dependence on launch conditions in short-reach step-index multimode polymer waveguides. Short optical links, especially those with several connection interfaces and utilising a restricted launch are likely to be subject to a modal noise power penalty. We therefore experimentally study the modal noise impact of restricted launches for a short-reach optical link employing a 50 x 50 gin polymer multimode waveguide. Lens launches resulting in small diameter input spots are investigated as are restricted launches from an 8 mu m core optical fibre. For a launch spot of 10 mu m diameter no impairment is observed for up to 9 dBo of mode selective loss, and for a fibre launch with a dynamic input movement of 6 mu m no impairment is seen for up to 8 dBo of mode selective loss.