title: Design, fabrication, and evaluation of a multichannel diffractive optic rotary joint.
abstract: A multichannel diffractive optic rotary joint was designed, fabricated by electron-beam lithography, and evaluated with regard to cross talk and to output signal power variations. High cross-talk margin (>25 dB) and low output signal power variations (<2 dB) were achieved. The sensitivity to input-light-beam wavelength uncertainty was investigated. Two design examples are presented. The first design eliminates cross talk due to unwanted diffraction orders and shows that for a ten-channel joint the wavelength uncertainty of an 850-nm emitting laser must be less than 8 nm. In the second design cross talk due to the second diffraction order is permitted, which results in a tolerance level that is three times better for wavelength uncertainty.
authors.affiliation: Photonics Laboratory, Department of Microelectronics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Johansson
authors.forename: S
authors.initials: S
authors.lastname: Hård