Multiple channel scanning device using optoelectronic switching

Abstract

An optical scanner employs a read/write head formed on an optoelectronic chip. The chip has a laser source and a diverging series of light guides interconnected with switches under control of a controller. The light from the light source is transmitted to multiple output apertures during reading operations, since, usually, less intensity is required to read data that to write it. This allows multiple channels to be read in at the same time. The light is directed to a selected output aperture during writing operations so that all of the light from the laser source is used for writing. In another embodiment, light from a small number of lasers is directed to a diverging series of light guides leading to multiple apertures, but the light fed into the input light guides comes from a small number of lasers, which could be one laser, or from a larger number of lasers, which could be two lasers. In this way, multiple channels can be written and read using the larger number of lasers during the write operation and the small number of lasers during the read operation. In either embodiment, the write operation involves modulating the emitted light, either by modulating the lasers directly or by using the switches on the optoelectronic chip. For scanning, the chip is oscillated by a motor, which could be a MEMS motor. Light emitted by the output apertures illuminates an array of small spots, in this embodiment, by imaging optics fixed relative to the scanned surface. This generates a rapidly sweeping array of light spots on the scanned surface. In alternative embodiments, the focusing optics are oscillated and the fiber array is held fixed, or the focusing optics and the fiber array are oscillated as a single assembly.