Andrew J. Daiber

Microholographic multilayer optical disk data storage

Micrometer-sized reflection holograms can be written into a rapidly rotating homogeneous photopolymer disk at the focus of a high-numerical-aperture beam and its retroreflection to implement high-capacity multilayer digital data storage. This retroreflection is generated by an optical system with positive unity magnification to ensure passive alignment of the counterpropagating beam. Analysis reveals that the storage capacity and transfer rate of this bit-based holographic storage system compare favorably with traditional page-based systems but at a fraction of the system complexity and cost. The analysis is experimentally validated at 532 nm by writing and reading 12 layers of microholograms in a 125-microm photopolymer disk continuously rotating at 3600 rpm. The experimental results predict a capacity limit of 140 Gbytes in a millimeter-thick disk or over 1 Tbyte with the wavelength and numerical aperture of Blu-Ray.

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. The system demonstrates that fixing by heating after recording gives adequate performance for multiplex holography in the perpendicular recording geometry. The postrecording heating procedure is preferred over high-temperature recording in the perpendicular geometry to achieve Bragg matching for the entire signal angular bandwidth.

Three-dimensional optical disk data storage via the localized alteration of a format hologram

Three-dimensional optical data storage is demonstrated in an initially homogenous volume by first recording a reflection grating in a holographic photopolymer. This causes the entire volume to be weakly reflecting to a confocal read/write head. Superposition of two or three such gratings with slightly different k-vectors creates a track and layer structure that specialized servo detection optics can use to lock the focus to these deeply-buried tracks. Writing is accomplished by locally modifying the reflectivity of the preexisting hologram. This modification can take the form of ablation, inelastic deformation via heating at the focus, or erasure via linear or two-photon continued polymerization in the previously unexposed fringes of the hologram. Storage by each method is demonstrated with up to eight data layers separated by as little as 12 microns.

Wavelength Filter with Integrated Thermal Control used as an Intracavity DWDM Laser Tuning Element

A thermally tuned silicon wavelength filter with integrated thermal isolation and control elements is described. Placed within the laser cavity of an external cavity semiconductor laser, this filter enables full-band tuning that meets all requirements for deployment in DWDM telecommunication systems

Holographic Storage without Holography: Optical Data Storage by Localized Alteration of a Format Hologram

We propose and demonstrate multi-layer storage in holographic photopolymer by locally altering the reflectivity of a factory-written reflection hologram at the focus of a single objective lens. Linear, two-photon and thermal writing mechanisms are demonstrated.

Thermally tuned external cavity laser with micromachined silicon etalons: design, process and reliability

A broadly tunable external cavity laser, employing thermally tuned etalons and laser-welding manufacturing is presented. The design of the tunable laser module is based on the quasi-planar manufacturing technology that is used for multiple other Intel products such as 10 Gb/s transponders and transceivers for Sonet and Ethernet applications. The laser cavity is defined at the output end by the gain chip facet and by an external mirror at the other end. An intracavity filter comprises two micromachined thermally-tuned silicon etalons manufactured to have slightly different free spectral ranges. The output optics of the external cavity laser are similar to those found in single-channel lasers. The density of optical components and the alignment precision required presented challenges for the development of scalable component placement processes and packaging. However, excellent performance has been obtained as evidenced by short-term stability under thermal and mechanical stress tests and long-term stability under accelerated stress tests.

Micro-Holographic Multi-Layer Optical Disk Data Storage

We demonstrate 12-layer storage of 5.84 Gbits per square inch via micro-holograms written and read at 0.532 nm from a 125 micron photopolymer disk continuously rotating at 3600 RPM. Scaling predicts a potential TByte capacity.