A photonic oscillator that can generate multi-tone oscillations in both the RF and optical domains is demonstrated. The oscillator consists of a simple closed optoelectronic loop comprising a CW laser source, an optical modulator, a photodetector, a low noise electrical amplifier, an electrical bandpass filter and single or multiple optical delay elements. Multi-tone oscillations with independent control of tone spacing and phase noise is demonstrated using two optical fiber delay lines as optical delay elements. The phase noise of the oscillator is systematically measured as a function of its parameters such as the photodetector current, the amplifier gain and oscillation frequency. Phase noise values better than -125 dBc/Hz at 100 kHz offset frequency are measured at various combinations of the above parameters. Multi-tone photonic oscillators using Mach-Zender or electroabsorption modulators are theoretically analyzed and experimentally demonstrated with the relative merits compared.
This paper reviews recent development and application of the infrared version of the liquid crystal light valve (LCLV). We describe delivered IR image projectors for advanced end-to- end laboratory testing of IR seeker and sensor systems. System performance characteristics are given. A newly developed version of the device has much higher contrast with low IR background image capability.
The authors report the operation of the Hughes Schottky diode-based silicon liquid crystal light valve (SLV) using readout light in the visible region. Limiting resolutions of 28 lp/mm limited by the Schottky diode periodicity, contrast ratios of >100:1, visible input light sensitivities of better than 50 (mu) W/cm2, and response times as fast as 5 ms have been measured. Both standard twisted nematic and homeotropically-aligned liquid crystal configurations have been utilized. The main parameter of this device is the leakage current of the Schottky diodes.