Marvin D. Drake

Waveguide hologram fingerprint entry device

The recording and entry of fingerprints into the local and na- tional databases is increasingly relying on optics to simplify and speed up this process. A prototype device for the entry of fingerprints that uses a waveguide hologram as part of the scheme for illuminating the finger is described. The use of the waveguide hologram enables reduction in the size, weight, and energy consumption of a fingerprint entry device (or live scan device). The entry device then becomes highly portable and thus useful in many office and field applications. Coupled with electronic or optical processing and storage along with telephone or radio trans- mission of the captured fingerprints, rapid identification of individuals be- comes a realizable goal. The components required for the prototype ho- lographic fingerprint entry device (HoloFED) including the light source, the illumination waveguide hologram, the imaging system and the stor- age, and processing system are discussed. Examples of fingerprints captured are shown. The trade-offs necessary for the implementation of the prototype are object-to-image distance, optical efficiency, weight, and cost.

Optical fingerprint recognition using a waveguide hologram.

We demonstrate the fabrication of a waveguide hologram and describe how a plane-wave output beam can be generated for the illumination of a finger for fingerprint image capture. Also, when using a diverging beam in the substrate as a reference wave, one obtains a set of gratings written in the hologram. The reflected light from the finger is spatially filtered by this hologram, providing bandpassed information back through the waveguide when it is viewed through the plate.

Low reflectance terminations and connections for duplex fiber-optic telecommunication links.

The signal-to-noise ratio of full duplex fiber-optic telecommunication links using a single fiber with directional couplers is shown to be extremely sensitive to reflections from fiber end terminations and fiber-to-fiber connections. This paper will examine a series of experimental measurements made to determine the reflectance coefficients of several different end terminations and types of connection.

Optical key distribution system using atmospheric turbulence as the randomness generating function: classical optical protocol for information assurance

Abstract. We describe an experimental laboratory system that generates and distributes random binary sequence bit streams between two optical terminals (labeled Alice and Bob). The random binary sequence is generated through probing the optical channel of a turbulent atmosphere between the two terminals with coincident laser beams. The two laser beams experience differential phase delays while propagating through the atmospheric optical channel. The differential phase delays are detected and sampled at each terminal to yield raw random bit streams. The random bit streams are processed to remove bit errors and, through privacy amplification, to yield a bit stream known only to Alice and Bob. The same chaotic physical mechanism that provides randomness also provides confidentiality. The laboratory system yielded secret key bit rates of a few bits/second. For external optical channels over longer channel lengths with atmospheric turbulence levels, secret bit rates of 10 s of bits/second are predicted.

Optical binary phase-only correlation system for rapid target recognition, discrimination, and tracking

This paper describes an optical correlator system that uses binary-phase-only filters (BPOFs) for target identification, tracking and discrimination. The optical system is a modification of previous correlator designs. The system incorporates a telephoto lens pair and simplifies the output optics such that the total optical-processor system length is reduced to fractions of a focal length. A Vernier scale adjustment of the optical Fourier transform is also made possible. Extensive software was developed to generate and manipulate target and filter files including the generation of BPOFs and the sequencing of files to drive the spatial light modulators. Examples are shown of autocorrelation and crosscorrelation of the target and filters.

Vernier scaling in shortened optical correlators

Vernier transform scaling is achieved in a shortened optical correlator by placing the input spatial light modulator (SLM) between the telephoto transform lens pair. Translating the SLM changes the Fourier transform scale but not the position of the transform plane.

Experimental comparison of optical binary phase-only filter and high-pass matched filter correlation

An experimental comparison of two optical correlation systems in their ability to do target detection, identification, and discrimination is described. A common set of four binary input images was used for the experiments, which included single and multiple target scenes. The set included symmetric and asymmetric objects. The two optical correlation systems compared were (a) a high pass matched filter (HPMF) VanderLugt system and (b) a binary phase-only filter (BPOF) system. In the HPMF system, the input image and filter are film-based, with the filter somewhat Gaussian apodized to achieve high passing. The BPOF system has one magneto-optical spatial light modulator as the input device, and another as the filter device. The experimental measurements compared were (1) target auto- and crosscorrelation, (2) auto- and crosscorrelation for multiple target scenes, (3) spatial extent of the correlation peaks, and (4) sidelobe levels in multiple target scenes. In spite of the fundamental differences in the correlators compared (i.e., film vs. real time image/filter), the use of binary imagery and high pass filters in both cases gave comparable results in target detection, identification, and discrimination. Both the similarities and the differences are described and summarized.

Practical System Design Considerations For Wideband Fiber Optic Links Using External Modulators

We investigated the application of integrated optic modulators (I0Ms) to wideband fiber optic communications systems. These integrated optic modulators differed in their electrode structures and method of optical launching. Signal-to-noise ratio, harmonic distortion, input impedance, and laser noise effects were measured as functions of modulation frequency and modulator bias voltage. We will present possible system design alternatives to improve operation of the IOM and performance of the overall fiber optic link.