Optical Signal Processing.
Abstract
We developed new analytical tools for predicting the performance of adaptive optical processors using feedback. Such systems are potentially unstable; new computer simulations were developed to model the instabilities and to guide corrective modifications of the hardware. We also developed new diagnostic tools that helped measure the complex valued impulse response of the system. We achieved notch depths of more than 32 dB over a 50 MHz band-width with an optical system having the equivalent of 500 tap weights. We also studied a generalization of the crossed Bragg cell architecture often used in signal processing. We derived the necessary geometry to obtain correlation functions that have an arbitrary spatial or an arbitrary temporal scaling; with these geometrics the optical processors can perform a wider variety of operations. We analyzed the properties that a reference waveform needs to function as a distributed local oscillator in heterodyne spectrum analyzers. The key finding is that the temporal spectrum of the reference bias term may contribute energy in the passband of interest, thereby reducing the dynamic range. We introduce the concept of the mixed transform that accurately represents the spatial and temporal structure of the reference waveform. We found that these effects can be controlled by placing a harmonic of the periodic reference waveform at the center of the passband and then to control its level through aperture weighting of the Bragg cell.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 31, 1986
- Accession Number
- ADA175388
Entities
People
- A. Vanderlugt
Organizations
- Harris Corporation