Summary form only given. For short haul (<30 m), moderate speed (<155 Mbps) communications with applications ranging from automotive wiring harness replacement to local ATM cable links, cost becomes the dominant issue. For such applications, we have proposed an alignment-tolerant, bi-directional link using a single large core plastic optical fiber (POF) between two analog/digital circuits that contain co-located emitter-detector pairs. The emitter is integrated into a hole in the middle of a large detector using the well-known epitaxial lift-off technique. The emitter can be a low cost light-emitting diode (LED) or a more directional resonant cavity LED (RCLED). The large core size provides a large tolerance to connector misalignment, providing low cost connector design. Using a novel approach for alignment studies between emitter and large core fiber, we have performed a Monte Carlo simulation of misalignment of our link based on a T.O. can-type connector design. In our simulation, we have taken into account the effects emitter size and directivity, the fiber core size, and detector size have on the link performance. We express our results in terms of an emitter-to-fiber (EF) alignment loss factor, a fiber-to-detector (FD) alignment loss factor. The total bi-directional alignment loss factor is equal to EF loss factor times FD loss factor.