Novel multi-channel photonic RF frequency converters for wideband telecom satellite payload applications

Abstract

RF frequency conversion is a key function of telecom satellite payloads. Hereafter are presented new photonic RF subsystem concepts supporting multi-channel, wideband frequency-conversion, thus drastically reducing the amount of equipment, for frequency down-and up-conversions respectively at the inputs and outputs of a digital processor. Proofof-concept demos are presented and the measured RF performance reviewed vs. predictions and system requirements.The so-called dual-band, multi-LO frequency-converter (DB-MLFC) concept is an extension of the multi-LO frequencyconversion scheme already proven by Thales Alenia Space. It makes use of a dual-drive modulator with wavelengthmultiplexed LO input and RF signal inputs in separate frequency bands. It can be applied to digital processor-based payloads and perform down-conversion of Ka or V-band sub-bands to the C-band of the processor input. The DB-MLFC concept was proven to support down-conversion of 2 and 3 sub-bands from the Ka (~30 GHz) and V (~50 GHz) bands to the C (~6 GHz) band of the processor input.The second concept called multi-RF frequency-converter (MRFC) consists in mixing multiple RF signals on separate optical carriers with an electrical LO signal into one electro-optical mixer. RF signals to undergo the same frequency conversion are combined via a WDM and fed into the optical input port of an electro-optical modulator, the RF port being driven by the LO. The RF performance of the MRFC concept, were measured with up-conversion of up to 8 Cband RF signals from the processor output to Ka-band payload output frequencies (~20 GHz).

Electro-absorption modulated laser for analog and digital satellite payload applications

“…Optical amplifiers are there either at the input or the output of the mixer or at both, in order to improve the RF conversion gain and noise figure performance. More advanced configurations taking benefit from WDM to implement multiple channels and support simultaneously multiple frequency-conversions, are possible and described for instance in [4]. The RF performance of such a photonic RF frequency up-converter was measured for input RF signals in C-band (around 6 GHz) as outgoing from a digital processor output port and an output frequency in Ka-band (around 20 GHz) corresponding to Ka-band payload transmit sections.…”