Free-space optical communications system transmits 10.7 Gbit/s

Nov. 1, 2008
Scientists at Discovery Semiconductors (Ewing, NJ), Science Applications International (Albuquerque, NM), the Air Force Research Laboratory (Kirtland AFB, NM), and Schafer (Albuquerque, NM) have created a satellite free-space optical communications system that transmits 10.7 Gbit/s at 1.55 µm wavelength

Scientists at Discovery Semiconductors (Ewing, NJ), Science Applications International (Albuquerque, NM), the Air Force Research Laboratory (Kirtland AFB, NM), and Schafer (Albuquerque, NM) have created a satellite free-space optical communications system that transmits 10.7 Gbit/s at a 1.55 µm wavelength; with a commercial +37 dBm optical-booster amplifier, it would do so over a distance of several tens of thousands of kilometers. The receiver—the key development—is preamplified and has an optical-delay interferometer and a balanced photoreceiver.

The transmitter-receiver pair is based on return-to-zero differential phase-shift keying. The receiver has a sensitivity of 27 photons per bit at 10.7 GHz, less than 1 dB from the quantum limit of 22 photons/bit, resulting in a bit-error rate of 1 × 10-9. The photodetector is integrated with a clock-and-data recovery (CDR) unit to allow bit-error-rate measurements. To simulate Earth-to-satellite links, the system was tested with a “turbulence box,” containing heating elements and fans, which showed that even under heavy scintillation, the CDR locked onto the data stream, and also confirmed that the return-to-zero format was more robust than a non-return-to-zero format. Contact Christoph Wree at [email protected].

Sponsored Recommendations

March 31, 2025
Enhance your remote sensing capabilities with Chroma's precision-engineered optical filters, designed for applications such as environmental monitoring, geospatial mapping, and...
March 31, 2025
Designed for compatibility with a wide range of systems, Chroma's UV filters are engineered to feature high transmission, superior out-of-band blocking, steep edge transitions...
March 31, 2025
Discover strategies to balance component performance and system design, reducing development time and costs while maximizing efficiency.
March 31, 2025
Explore the essential role of optical filters in enhancing Raman spectroscopy measurements including the various filter types and their applications in improving signal-to-noise...

Voice your opinion!

To join the conversation, and become an exclusive member of Laser Focus World, create an account today!