| A thorough study of ultralow bit-error-rate (BER) of free-space optical interconnects (FSOIs) is presented in this thesis. The optimized BER is obtained based on the optimization of the system design. The key problems affecting the performance of FSOIs are studied, which include the relative intensity noise of VCSELs, hologram scattering, aberration of the optical elements, power loss, crosstalk of different channels, and misalignment of components.; The relative intensity noise characteristics of one-mode and two-mode VCSELs are analyzed. The analysis is based on the multimode equations of VCSELs. The wavelength stability and VCSEL beams collimation are also studied.; The hologram array design for high diffraction efficiency is presented. The scattering from the hologram as a noise source is measured, and its effect on detection procedure is calculated. Aberrations due to the bulk optics in the FSOI system are calculated and ways for correction of the aberrations are discussed.; The effect of the crosstalk among different channels as a major noise source is studied. An optical model for design of the system parameters such as VCSEL beam diameter, size and apodization of the hologram, and size of the detector is given based on the detection efficiency and crosstalk analysis of the system.; The overview of the systems and the techniques used for fabrication are provided. A model for 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 reliability in terms of BER of FSOIs is examined with double Possion statistics based on detailed analysis of system. The BER is thermal noise and RIN limited in FSOIs. The simulations based on the BER model show that a BER of 10{dollar}sp{lcub}-18{rcub}{dollar} is achievable for the current FSOI system. |
