Recently, our group published a paper titled "Silicon four-quadrant photodetector working at the 1550-nm telecommunication wavelength" in Optics Letters. In this paper, we reported a type of four-quadrant photodetector using silicon as the material of photosensitive region, which worked at the 1550-nm telecommunication wavelength (longer than the long-wavelength limit of bulk silicon, about 1.1 micrometer), and demonstrated the beam positioning and measurement of beam deflection angle at this wavelength.

URL: https://opg.optica.org/ol/abstract.cfm?uri=ol-47-16-4048