Optical technology offers simple interconnection schemes with straightforward layouts that support complex logical interconnection patterns. The Passive Optical Star (POS) is often suggested as a platform for implementing the optical network: Logically it offers an all-to-all broadcast capability. Indeed, it seems to give a good support for intensive parallel computations involving massive transfer of information and broadcast, such as Video and Graphic applications. We investigate the use of POS optical technology as the communication medium for parallel computing. In particular, a feature of parallel models which is extremely important for the simplicity of algorithm design and program portability is the scalability property or self-simulation capability. It states that when a computation achieves a certain speedup on a large machine with many processors, then it achieves a similar speedup on any smaller machine (relative to the number of processors). We show that the POS is indeed scalable, namely, we present a randomized algorithm for an n-processor n-wavelength POS that does not assume global knowledge and that simulates a kn-processor kn-wavelength POS with a slowdown of O(k + \log ^* n). We then show how to route k-relations on the n-processor POS in O(k \log^* n) steps, thus proving that the power of broadcast incorporated in the POS model may be applied to point-to-point communication problems as well (there is a higher lower-bound for the point-to-point n-processor OCPC).