Richard A. Baumgartner

Microwave integrated optical modulator

A Ti‐diffused lithium niobate, traveling wave modulator has been fabricated and tested at microwave frequencies. A Mach–Zehnder interferometer optical configuration and a coplanar waveguide electrical transmission line are used. For a 4‐mm interaction length, the modulator has a 3‐dB bandwidth of 13 GHz and requires only 2 V to switch at λ=840 nm. The frequency response is measured directly using an ultrahigh speed photodiode, and the test setup therefore constitutes the highest bandwidth efficient electro‐optical transmission system ever reported.

Amplitude insensitive delay lines in an accoustic imaging system

A delay circuit for providing signal delay within an acoustic imaging system is provided. Reflected acoustic signals are transformed into electrical signals and are used to reproduce images of objects. Delay lines along the electrical signal path are used to focus the images compensating for asynchronism of electrical signals caused by variations in the length of acoustic signal paths.

A 1.5 GOPS analog CMOS array processor with integrated optical image acquisition for position encoding applications

An analog CMOS IC performs 2-D image cross-correlations to facilitate optical navigation across low contrast surfaces, such as paper. The chip includes a 25 K frames/second 34/spl times/68 active pixel photo-receiver array for capture of optical navigation reference images. Each active pixel utilizes an embedded feedback loop to maintain adequate transient response. Low spatial frequency illumination and photocell sensitivity variations are removed from the image data with local difference computation circuits as each row of image data is transferred out of the photo-receiver array. The captured images are transferred to a 32/spl times/64 array of analog signal processing cells which perform a series of nearest-neighbor 2-D cross-correlations between a previously stored image and the most recently acquired comparison image. The computation array also includes means for moving a stored reference image within the array to improve long range encoding accuracy. The correlation results are passed to an off-chip controller for translation into relative motion data.

A Traveling Wave, Microwave Optical Modulator

A Ti-diffused lithium niobate, traveling wave modulator has been fabricated and tested. A Mach-Zehnder interferometer optical configuration and a coplanar waveguide electrical transmission line are used. For a 4mm interaction length, the modulator has a 3dB bandwidth of 13 GHz and requires only 2 volts to switch at λ = 840 nm. The frequency response is measured directly using an ultra-high speed photodiode, and the test set-up therefore constitutes the highest bandwidth electrooptical transmission system ever reported.