Abstract: An optical system affixed to an electronic apparatus is provided, including a first optical module, a second optical module, and a third optical module. The first optical module is configured to adjust the moving direction of a first light from a first moving direction to a second moving direction, wherein the first moving direction is not parallel to the second moving direction. The second optical module is configured to receive the first light moving in the second moving direction. The first light reaches the third optical module via the first optical module and the second optical module in sequence. The third optical module includes a first photoelectric converter configured to transform the first light into a first image signal.

Abstract: A data transmission system is disclosed. The data transmission system includes at least one signal processing device, at least one conversion device, at least one antenna device, and at least one flexible printed circuit board. The at least one signal processing device is configured to generate or receive at least one data. The at least one conversion device is configured to transform between the at least one data and an optical signal. The at least one antenna device is configured to obtain the at least one data according to the optical signal, and configured to receive or transmit the at least one data wirelessly. The at least one flexible printed circuit board includes at least one conductive layer and at least one optical waveguide layer. The at least one optical waveguide layer is configured to transmit the optical signal.

Abstract: A cylindrical package includes a cylindrical housing; a pedestal at a bottom of a cylindrical space surrounded by the cylindrical housing; an optical splitter in the cylindrical space and over the pedestal; a first photodetector in the cylindrical space and over the pedestal, wherein the first photodetector is configured to be optically coupled to the optical splitter; and a second photodetector in the cylindrical space and over the pedestal, wherein the second photodetector is configured to be optically coupled to the optical splitter.

Abstract: A cylindrical package includes a cylindrical housing; a pedestal at a bottom of a cylindrical space surrounded by the cylindrical housing; an optical splitter in the cylindrical space and over the pedestal; a first photodetector in the cylindrical space and over the pedestal, wherein the first photodetector is configured to be optically coupled to the optical splitter; and a second photodetector in the cylindrical space and over the pedestal, wherein the second photodetector is configured to be optically coupled to the optical splitter.

Abstract: A superlattice infrared photodetector is disclosed, which can be fabricated easily by molecular beam epitaxy, has low power consumption and small dark current. Furthermore, the working temperature to operate the detector under background limited performance can be achieved by cooling down to the liquid nitrogen temperature. That is, the front and rear sides of the superlattice structure are added with blocking layers with sufficient height and width. The thickness is about 50 nm and the height of the energy barrier must be higher than the bottom of the second miniband of the superlattice structure by a value of more than 10 meV. Thereby, with the generation of photocurrent, the dark current is reduced at the same time. Therefore, the ratio of the photocurrent to the dark current can be improved effectively so that the working temperature for the background limited performance is increased vastly to even higher than 77 K.