Silicon-photonics multi-wavelength common-gain tunable laser providing both source and pump for an amplified transceiver.

We propose and demonstrate a silicon-photonics-based laser that outputs multiple independently tunable wavelengths using a single InP gain element. We use it to generate a C-band tunable source for a coherent transceiver and simultaneously a 1480-nm source to pump an Er-doped fiber amplifier on the transmitter output.

Silicon-photonic laser emitting tunable dual wavelengths with highly correlated phase noise.

A silicon-photonic tunable laser emitting two tunable wavelengths simultaneously is demonstrated. The laser consists of a single semiconductor optical amplifier that provides shared gain and a silicon-photonic chip that provides wavelength selections. A total optical power of 29.

The feasibility of an inverse geometry CT system with stationary source arrays.

Purpose: Inverse geometry computed tomography (IGCT) has been proposed as a new system architecture that combines a small detector with a large, distributed source. This geometry can suppress cone-beam artifacts, reduce scatter, and increase dose efficiency. However, the temporal resolution of IGCT is still limited by the gantry rotation time.

Comparison of entrance exposure and signal-to-noise ratio between an SBDX prototype and a wide-beam cardiac angiographic system.

The scanning-beam digital x-ray (SBDX) system uses an inverse geometry, narrow x-ray beam, and a 2-mm thick CdTe detector to improve the dose efficiency of the coronary angiographic procedure. Entrance exposure and large-area iodine signal-to-noise ratio (SNR) were measured with the SBDX prototype and compared to that of a clinical cardiac interventional system with image intensifier (II) and charge coupled device (CCD) camera (Philips H5000, MRC-200 x-ray tube, 72 kWp max). Phantoms were 18.

Scanning-beam digital x-ray (SBDX) technology for interventional and diagnostic cardiac angiography.

The scanning-beam digital x-ray (SBDX) system is designed for x-ray dose reduction in cardiac angiographic applications. Scatter reduction, efficient detection of primary x-rays, and an inverse beam geometry are the main components of the entrance dose reduction strategy. This paper reports the construction of an SBDX prototype, image reconstruction techniques, and measurements of spatial resolution and x-ray output.

Comparison of vessel contrast measured with a scanning-beam digital x-ray system and an image intensifier/television system.

Vessel contrast was measured in the fluoroscopic images produced by a scanning-beam digital x-ray (SBDX) system and an image intensifier/television (II/TV) based system. The SBDX system electronically scans a series of pencil x-ray beams across the patient, each of which is directed at a distant small-area detector array. The reduction in detected scatter achieved with this geometry was expected to provide an increase in image contrast.

Digital wavelength-multiplexed holographic data storage system.

We present a novel digital holographic data storage system based on wavelength multiplexing in 90 degrees geometry, using an automated tunable diode laser and a lithium niobate crystal. The automatic storage and retrieval of a 60-kbyte data file, as well as the limitations and future implementations of the system, are discussed.

Digital holographic storage system incorporating thermal fixing in lithium niobate.

We describe a digital holographic data storage system that uses in situ thermal fixing to achieve nonvolatile readout. The system was used to store and fix 530 holograms representing 1.7 MB of digital data.

Signal detection for page-accessoptical memories with intersymbol interference.

We propose a technique for data detection in a two-dimensional page-access optical memory. The technique combines sequence detection by the use of the Viterbi algorithm with decision feedback to improve the bit-error-rate performance in a system corrupted by intersymbol interference. It has an advantage in that it can be operated on a row-by-row basis as data are output from the optical detector.

A bound on the energy resolution required for quantitative SPECT.

Scattered radiation is one of several physical perturbations that limit the accuracy of quantitative measurements in single-photon emission computed tomography (SPECT). Improvement in detector energy resolution leads to a reduction of scatter counts and a corresponding improvement in the quantitative accuracy of the SPECT measurement. In this study, simulated SPECT projections of a simple myocardial perfusion phantom were used to investigate the effect of detector energy resolution on the data.

Coded-wavelength multiplex volume holography.

We introduce the technique of coded-wavelength multiplex holography. We encode each wavelength with a discrete angular spectrum of plane waves, so that the total number of multiplexed holographic pages equals the number of wavelengths multiplied by the number of discrete wave vectors at each wavelength. Encoding with different propagation angles further permits one to utilize the properties of grating degeneracy to assemble an image from a mosaic of smaller images and to multiplex such images at different wavelengths.

Encrypted holographic data storage based on orthogonal-phase-code multiplexing.

We describe an encrypted holographic data-storage system that combines orthogonal-phase-code multiplexing with a random-phase key. The system offers the security advantages of random-phase coding but retains the low cross-talk performance and the minimum code storage requirements typical in an orthogonal-phase-code-multiplexing system.

Volume holographic storage and retrieval of digital data.

A multiple page fully digital holographic data storage system is demonstrated. This system is used to store and retrieve digital image and compressed video data with a photorefractive crystal. Architecture issues related to spatio-rotational multiplexing and novel error-correcting encoding techniques used to achieve low bit-error rates are discussed.

Recall of linear combinations of stored data pages based on phase-code multiplexing in volume holography.

We describe a novel method for the recall of linear combinations of stored data pages in a volume holographic memory based on phase-code multiplexing. Recall is demonstrated by use of a compound phase-and-amplitude spatial light modulator in the reference beam path.