Abstract

A new type of real-time optical rf spectrum analyzer is proposed that mainly consists of a 1-D surface-emitting microlaser array, a sampling and hold circuit (S/H), and a CCD photodectector. An rf input signal is sampled by the S/H within a frame time of the system, and the sampled values are output to the matrix-addressed microlaser array in parallel. Using this scheme, the light intensity distributions are equivalent to the sampled values of the rf signal. The light distributions are then Fourier transformed and processed with a low-pass filter to remove the periodicity of the laser array. The output of the photodetector is proportional to the power spectrum content of the rf input. This architecture has the advantage of adjustable thresholding capability for the input signal by biasing a dc voltage to the common negative of the microlaser array. The system’s time–bandwidth product is limited by the number of microlaser elements in the array. The resolution and speed of the system are dependent upon the data rate and number of pixels of the photodetector, the sampling frequency of the S/H, and the number of microlasers.

© 1991 Optical Society of America