Microoptical CDM-technique for satellite communications

Multiplexing techniques such as wavelength division (WDM) and code division multiplexing (CDM) are of interest to increase the number of data channels in the case where the number of physical channels is limited. The situation occurs, for example, in satellite communications. Both, WDM and CDM techniques have been considered earlier in connection with the use of sub-picosecond optical pulses [1]. Here, we discuss, in particular, the implementation of the CDM approach. In CDM de/multiplexing are performed by a correlation filter. In our case, the realization of the correlation filter is achieved by a microoptical solution. Key component for the implementation of the filter is a 1D retroreflector array that is tilted around its axis. In combination with a suitable masks, one can implement a specific filter impulse response. We report on the fabrication of the retroreflector array, demonstrate the performance of the device with fs-pulses and discuss the potential of the approach for satellite communication links. [1] H. Knuppertz, M. Bohling, J. Jahns, Optical clocking and interconnection using short pulses and CDM, ICO Top. Meet. Optoinformatics 2006, St. Petersburg, Russia.