Tolerance analysis of packaging for free-space optical interconnects

A bi-directional free-space holographically interconnected crosspoint switch and FFT processor are under development at the Optoelectronic Computing Systems Center at the University of Colorado at Boulder. Both systems include two sets of optoelectronic modules which communicate with each other using free-space interconnects. The size of the detector array and the vertical-cavity surface-emitting laser (VCSEL) array on each module is 8 by 8. The packaging of such system is critical for the proper operation of the systems. The overview of the systems and the techniques used for fabrication are provided. A model f the tolerance analysis of the system is presented, in which the misalignments of the VCSEL array, microlens array, hologram array, Fourier lens, and the detector array are taken into account. The fabrication tolerances for each component required for correct system operation is given. Statistical analysis based on Monte Carlo simulation for the detection efficiency and signal-to-noise ratio is calculated given misalignment distribution of 17 misalignments of the components of the system. The methods used for the alignment of the system are discussed.