An opto-electronic transient waveform digitiser is detailed which combines the massive bandwidth of commercially available optical components with the high resolution sampling capabilities of state-of-the-art electronic analogue to digital converters (ADCs). Core to the success of a 64 GSa/s sampling rate has been the development of an automated temperature stabilised fibre delay line structure. This generates multiple replicas of short incoming pulses, which are then digitised using the Vernier sampling technique. The successful temperature stabilisation of the optical sub-components now offers the potential for an environmentally rugged fibre based system, with small system footprint, and low power requirements through the use of a single electronic ADC and compact diode laser technology. System modelling indicates that the fibre delay line architecture performance could currently support very high sample rates, with the total system sample rate scaling directly with future electronic ADC improvements.
An optically controlled RF/microwave/mm-wave phased array antenna has been developed operating at 10 GHz with 30 kHz reconfiguration rate via the use of a micromachined silicon Spatial Light Modulator. A communications function has been demonstrated with a variety of Phase Shift Keying modulation schemes (BPSK, QPSK, MSK) at data rates up to 200 Mbit/s and low BER (<1×10-9). A single channel has been demonstrated at 35 GHz. The properties of photonic components are taken advantage of in several ways: (i) since the carrier frequency is derived from heterodyning of lasers, it is tuneable from almost DC-100 GHz, (ii) the use of optical fiber allows for EMI immune antenna remoting, and (iii) the wide information bandwidth of optical modulators, which in this configuration is carrier frequency independent. The above is achieved in a lightweight and compact format, with considerable scope for further reductions in size and weight.
A low phase noise optoelectronic source has been developed operating at 10 GHz. Custom surface acoustic wave (SAW) devices operating at high frequency and high acoustic power have been developed and are used as the critical element in an optical phase locked loop. Improved performance could be attained via lasers with larger control loop bandwidths. The source is antenna remoteable via the use of optical fibre and is compact and lightweight, suggesting applications in phased array radar.