LED Technologies & Properties

LED is a two-lead semiconductor light source. LEDs are small and are commonly used as indicator lamps in electronic devices Due to the increased design flexibility, efficient use of power and environmental benefits the use of LEDs as lighting, data communication and signalling devices is growing in many applications such as space, aviation and automotive lighting, advertising and traffic signals The use of new semiconductor compounds based on GaN, GaP, InP and GaAs allows to cover a wider light-emitting range

Schematic of the QKD source a semiconductor optical amplifier

Fast optical source for quantum key distribution based on semiconductor optical amplifiers

A novel integrated optical source capable of emitting faint pulses with different polarization states and with different intensity levels at 100 MHz has been developed. The source relies on a single laser diode followed by four semiconductor amplifiers and thin film polarizers, connected through a fiber network. The use of a single laser ensures high level indistiguishability in time and spectrum of the pulses with the four different polarizations and three different levels of intensity.

Radiation testing board with six HV optocouplers

Low Temperature Radiation Test of High Voltage Optocouplers for Space Applications

In space applications, optocouplers may need to work at very low temperatures. Under this low temperature operating conditions, the device degradation subjected to radiation exposure may show different behaviour compared to a standard radiation test under room temperature. The purpose of this paper is to analyse the effects of proton displacement damages up to 8•1011p/cm2 and total ionisation dose up to 100Krad (Si)) at room and low temperature (i.e. 25ºC and -40ºC) on custom assemblies of High Voltage (HV) Optocouplers. The HV opto-coupler assembly, radiation setups for low temperature Gamma and Displacement Damage radiation tests are described in detailed.

Entangled Photon Source assembled.

Opto-mechanical design and assembly

The efficient generation of photon pairs requires very strict characteristics on the illuminating beam, such e.g. its size, shape, and polarization state. For these photon pairs to be entangled in their polarizations there must be a superposition of two distinct pair-generation possibilities each with orthogonal polarized photon pairs. To achieve this with a single nonlinear crystal we have chosen a set-up based on Sagnac interferometer [3]. Thus, beams must travel equal optical paths along both sides and focus on the crystal at the same point.

1. Distribution of pairs of entangled photons using the International Space Station (ISS). Entangled photon pairs are distributed to two separated places on Earth.

Quantum Transceiver for secure Space Communications

Quantum communications offers many advantages for secure data transmission, e.g. confidentiality, integrity, eavesdropper’s detectability. Information is encoded in quantum bits (qubits), intrinsic physical properties, such as polarization of a photon. Quantum physics allows encoding information using the correlation between two or more particles (photons, atoms). Quantum Key Distribution (QKD) is one of the innovative methods of information processing that emerged from the properties of “superposition of states” and “entanglement”.