Abstract: An optical head of a type useable in a optical disk reader/writer is provided. The optical head has a low profile, e.g., in a vertical direction parallel to the disk spin axis, such as less than about 5 mm preferably less than about 3 mm. Substantially all components of the optical system, including a laser source, objective lens, intervening optics and photo detector are provided in the optical head and mounted in a fixed position with respect to one another. Substantially all optical components of the optical head are moved as a unit, e.g., during tracking and/or focusing. Preferably, the optical head is fabricated using wafer scale and/or stacking technologies, e.g., stacking substantially planar components to achieve the final optical head configuration.

Abstract: An optical head of a type useable in a optical disk reader/writer is provided. One of the optical elements is provided in a fashion that one or more optical parameters or characteristics of the system are invariant, regardless of whether the one optical element is used, or not. In one embodiment the optical element is a beamshaper. In order to provide the desired invariant property, the surfaces of the optical element are preferably formed with high accuracy. One manner of economically achieving high accuracy is to measure errors or imperfections in a first formed, preferably etched, surface and adjust the shape or position of a second aligned etched surface so as to at least partially compensate for the errors or imperfections.

Abstract: An interconnection network for interconnection in parallel of a large number (N) of processing elements (PE). The network includes three serial switching stages. The first stage in which the processing elements arc grouped in r clusters of k processing elements each comprising many small fast electronic switches, one for each cluster. The second stage comprises a large number (N) of optical channels, one for each of the N processing elements. The third stage comprises k photodetectors for each of the clusters and electronic switches of the type in the first stage. Each cluster controls k light sources, one for each channel and k photodetectors in the cluster. Interconnection between processing elements in a common cluster are made solely by way of an electronic switch. Interconnection between processing elements in different clusters is made via the optical channels and one or two of the electronic switches.