Novel coding schemes for dual wavelength quantum cascade laser‐based free space optical links

Free-Space Optical Quantum Key Distribution Using Intersatellite Links

Communication schemes employing quantum entanglement open a wide field of possible applications with properties outperforming their classical counterparts. Promising examples are quantum key distribution, quantum dense coding, and quantum state teleportation. We investigate the potential of quantum cryptography, i.e. quantum key distribution (QKD), with special emphasis on the demands and oppor...

Frequency stability of a dual wavelength quantum cascade laser.

We characterized the dual wavelength operation of a distributed Bragg reflector (DBR) quantum cascade laser (QCL) operating at 4.5 μm using two independent optical frequency discriminators. The QCL emits up to 150 mW fairly evenly distributed between two adjacent Fabry-Perot modes separated by ≈11.6 GHz. We show a strong correlation between the instantaneous optical frequencies of the two lasin...

Gain competition in dual wavelength quantum cascade lasers.

We investigated dual wavelength mid-infrared quantum cascade lasers based on heterogeneous cascades. We found that due to gain competition laser action tends to start in higher order lateral modes. The mid-infrared mode with the lower threshold current reduces population inversion for the second laser with the higher threshold current due to stimulated emission. We developed a rate equation mod...

New Results in DF Relaying Schemes Using Time Diversity for Free-Space Optical Links

Frequency dissemination with free-space optical links

Optical clock technology is very certain to be integrated in the next high precision time standards. The demand for higher accuracy in time synchronization makes the use of free-space optical links necessary for frequency dissemination, especially if mobile partners are involved. These links are the most suitable solution in order to disseminate high frequencies in between satellites, ground st...