Superresolution technology for reduction of the far-field diffraction spot size in the laser free-space communication system

2003 ◽  
Vol 228 (4-6) ◽  
pp. 271-278 ◽  
Author(s):  
Jia Jia ◽  
Changhe Zhou ◽  
Liren Liu
Keyword(s):  
Communication System ◽  
Free Space ◽  
Spot Size ◽  
Diffraction Spot ◽  
Far Field ◽  
Space Communication ◽  
Free Space Communication

A novel free space communication system using nonlinear InGaAsP microsystem resonators for enabling power-control toward smart cities

2019 ◽  
Vol 26 (4) ◽  
pp. 2317-2328 ◽  
Author(s):  
P. Sivakumar ◽  
Regonda Nagaraju ◽  
Debabrata Samanta ◽  
M. Sivaram ◽  
Mhd. Nour Hindia ◽  
...  
Keyword(s):  
Power Control ◽  
Communication System ◽  
Free Space ◽  
Smart Cities ◽  
Space Communication ◽  
Free Space Communication

FEASIBILITY OF AN OPTICAL FREQUENCY MODULATION SYSTEM FOR FREE-SPACE OPTICAL COMMUNICATIONS

2006 ◽  
Vol 16 (02) ◽  
pp. 559-566 ◽  
Author(s):  
SERGE LURYI ◽  
MIKHAIL GOUZMAN
Keyword(s):  
Frequency Modulation ◽  
Communication System ◽  
Free Space ◽  
Single Frequency ◽  
Optical Frequency ◽  
Space Communication ◽  
Mid Infrared ◽  
Limiting Amplifier ◽  
Receiver System ◽  
Free Space Communication

We consider a free-space communication system based on optical frequency modulation (FM), where the information is encoded by a time-variable wavelength. As is well known, broadband FM systems use a transmission bandwidth that is larger than the signal's information bandwidth, thus enabling an enhancement of the signal-to-noise ratio (SNR) and hence the effective information rate per unit transmitter power. Because of the atmospheric conditions, any optical free-space communication system, contemplated at a terrestrial level, must operate at mid-infrared wavelengths in the range λ = 2.5 2.8 μ m . Development of rapidly tunable single-frequency lasers in this wavelength range is quite feasible, based on the current experience with tunable telecom lasers at 1.5 μm. Nevertheless, there is no currently available optical FM system. The main difficulty is associated not so much with the tunable optical sources, as with the implementation of a wavelength-discriminating receiver system that would take advantage of the enhanced SNR. In our view, the key enabling solution is optical superheterodyne with a local oscillator implemented as a tunable mid-infrared laser similar to that at the source. The intermediate frequency can be tuned to lie either in a frequency range directly accessible to electronic limiting amplifier and frequency discriminator or, in a multichannel system, to a second heterodyne in the terahertz range.

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