Optical parallel interconnection system is essential for the high-speed data transmission in the asynchronous transfer mode (ATM) switching system which should handle tens of thousand channels of 156 Mbit/s wideband services for future broadband integrated services digital networks (B-ISDN). To overcome the limits of electrical interconnects in board-to-board level, this thesis propose the optical interconnects using an optical fiber ribbon.
Effects of the receiver bandwidth increase on the performance of the optical parallel interconnection systems are described. The dominant effects are the skew, the optical power penalty due to the receiver bandwidth increase, the crosstalk between devices in a front-end array, the signal degradations due to the bandwidth limitation, and the margin. To maintain an appropriate eye margin and to get low optical power penalty within the increased skew range, the ratio between the crosstalk capacitance and the total input capacitance needs to be restricted for a given operating speed. The low crosstalk capacitance is very important in high speed optical parallel interconnections because the total input capacitance is small. When designing a practical fixed level decision (FLD) receiver circuits, it is possible to increase the allowable skew by increasing the receiver bandwidth. Using the calculated results and the optical power budget, we can design the FLD receiver circuit with an optimum transfer characteristic for large allowable skew.
A large alignment-tolerant coupling scheme of the laser diode (LD) array into the single-mode fiber (SMF) array is proposed. A tapered waveguide array is used as an intermediate coupling device to improve the lateral misalignment tolerance up to 6 m. The theoretical and experimental results show that the proposed passive alignment scheme with the flip-chip solder-bump technique can provide a simple (low-cost) packaging method for the LD/SMF array modules. This coupling scheme will also find wide applications in the hybrid integration of optoelectronic devices that are flip-chip bonded on silicon substrate.
A p-i-n photodiode (PD) array having the small crosstalk capacitance is fabricated for the high-speed optical receiver array. Then, we packaged the optical fiber/PD array modules, proposing a simple time-saving alignment method. External coupling efficiencies are about 95 % for both the SMF/PD array module and the MMF/PD array module. The fabricated four channel front-end array has 3-dB bandwidth of 1 GHz.