Optical Intersatellite hybrid network links based on WDM technology

Optical intersatellite hybrid networks, make it possible high speed communication with the advantages of small size and weight, low power consumption, high immunity to interference. We present an optical intersatellite network based on wavelength division multiplexing technology; the system is composed by one fixed node, a HAP, high altitude platform, in a quasistationary position at an altitude of 30 km from Earth surface, and a mobile node, on a LEO orbit which communicates with HAP and other eight LEO microsatellites. The choice of microsatellites number guarantees a good coverage of a target area and a continuous data transfer from slave nodes to master, with the consequent increase of communication capacity. HAP motion makes it possible to configure an ad-hoc network for monitoring of natural and man-made disaster, or every emergency application. Main constraints affecting the system performance concern on Doppler effect suffered by the signal, due to relative motion between satellites. The optical subsystem is composed by semiconductor laser, transmitting on ITU grid, an EDFA preamplifier and a direct detection receiver scheme. Signal to noise ratio will be evaluated as a function of the optical received power, EDFA gain, distance between satellites, for two different modulation formats, OOK and DPSK.