Axsun Technologies, Inc.

Massachusetts Institute of Technology

Christopher C Cook

Dale C Flanders

Michael Francis Miller

Minh Van Le

Walid A Atia

Mark E Kuznetsov

Peter S Whitney

Petros Amestis Kotidis

James Zambuto

James W Getz

Xiaomei Wang

Steven F Nagle

An optical probe for emitting and/or receiving light within a body comprises an optical fiber that transmits and/or receives an optical signal, a silicon optical bench including a fiber groove running longitudinally that holds an optical fiber termination of the optical fiber and a reflecting surface that optically couples an endface of the optical fiber termination to a lateral side of the optical bench. The fiber groove is fabricated using silicon anisotropic etching techniques. Some examples use a housing around the optical bench that is fabricated using LIGA or other electroforming technology. A method for a forming lens structure is also described that comprises forming a refractive lens in a first layer of a composite wafer material, such as SOI (silicon on insulator) wafers and forming an optical port through a backside of the composite wafer material along an optical axis of the refractive lens. The refractive lens is preferably formed using grey-scale lithography and dry etching the first layer.

SOI lens structure for medical probe

A process monitoring system determines a spectral response of a process material. This system has a tunable laser for generating an optical signal that is wavelength tuned over a scan band and an optical probe for conveying the optical signal to the process material and detecting the spectral response of the process material. The optical probe expands a beam of the optical signal to a diameter of greater than 10 millimeters. This avoids one of the difficulties with monitoring these process applications by ensuring that the spectroscopy measurements are accurate and repeatable. It is desirable to sample a relatively large area of the processed material since it can be heterogeneous. Additionally the large area mitigates spectral noise such as from speckle.

Spectroscopy probe and material processing system

To address counterfeit problems, for example, we propose a secure, flexible, and cost-effective authentication solution that can be integrated into conventional distribution logistic systems. The proposed solution for product authentication and distribution channel validation comprises three major components: 1) machine-readable Raman-active chemical taggant; 2) a taggant reader; and 3) a taggant eraser. The proposed solution is to control and validate the distribution channel by authenticating the origin of products. Authentication is accomplished by verification of distinct taggants associated with the articles, such as on its label, along with other product distribution information in optical, spatial-encoding indicia, such as a barcode. The taggant information is used to identify, validate, and distinguish the origin of the source of the articles, such as goods or products. The taggant material is thereafter rendered unreadable by modifying the taggants to make obtaining the information unfeasible, thereby controlling the taggants' lifecycle.

Erasable taggant distribution channel validation method and system

A process for patterning dielectric layers of the type typically found in optical coatings in the context of MEMS manufacturing is disclosed. A dielectric coating is deposited over a device layer, which has or will be released, and patterned using a mask layer. In one example, the coating is etched using the mask layer as a protection layer. In another example, a lift-off process is shown. The primary advantage of photolithographic patterning of the dielectric layers in optical MEMS devices is that higher levels of consistency can be achieved in fabrication, such as size, location, and residual material stress. Competing techniques such as shadow masking yield lower quality features and are difficult to align. Further, the minimum feature size that can be obtained with shadow masks is limited to &tilde;100 &mgr;m, depending on the coating system geometry, and they require hard contact with the surface of the wafer, which can lead to damage and/or particulate contamination.

Process for integrating dielectric optical coatings into micro-electromechanical devices

A thin membrane having a thin film optical coating thereon is formed from multiple layers of different materials in which the overall stress of the thin film is not more than 15 MPa. Such films can be formed through thermal evaporation with ion assist, by directing an electron beam on a source and evaporating material from the source onto a thin flexible membrane while directing an ion stream onto the membrane. The current of the source of the ion stream should be sufficient to provide a thin film coating that has substantially no porosity. Successive applications at constant current can be deposited, while varying the voltage of the ion stream. The stress of the thin films deposited under each different voltage can be evaluated and the voltage at which the stress is acceptably low can be determined.

Controlled stress optical coatings for membranes

A Fabry-Perot filter has at least two mirror structures defining a resonant cavity. This filter is tunable by modulating an optical distance between the mirror structures. To accommodate a wide bandwidth of operation or accommodate two spectral bands, the mirror structures are made from two stacked, single-band mirrors. In more detail, the mirror structures comprise a substrate; a first mirror is deposited on the substrate, with an index matching coating between the substrate and the first mirror. The second mirror is stacked on the first mirror. The mirrors are symmetric relative to each other, such that the index of a first mirror in the second spectral band has an effective index of about one. In contrast, the second mirror has an effective index of about one in the first spectral band.

Dual-band fabry-perot mirror coating

A method of generating an anti-reflection optical coating on a laser diode includes determining a preliminary design for the coating, fabricating the coating on a first laser diode using an in-situ optical monitoring technique and measuring the performance of the laser diode. The steps of modifying the anti-reflection coating on the laser diode and measuring the performance of the laser diode are repeated until a performance maximum is determined. Another anti-reflection coating is fabricated a second laser diode and the performance of the laser diode is measured. Again, the steps of modifying the anti-reflection coating on the laser diode and measuring the performance of the laser diode are repeated until another performance maximum is determined. The above steps are repeated with additional laser diodes, as necessary, until a global performance maximum is determined. The coating parameters for the anti-reflection coating corresponding to the global performance maximum are used as the final anti-reflection coating design.

Method for generating an anti-reflection coating for a laser diode

A process for fabricating an optical membrane from polycrystalline silicon comprises first forming a sacrificial layer on a handle wafer. Concavities are etched into the sacrificial layer. Polycrystalline silicon membrane layer is then formed on the sacrificial layer. The polycrystalline membrane layer is subsequently polished to achieve the predetermined membrane thickness and surface smoothness, annealed, and then patterned. Finally, the sacrificial layer is removed to release the membrane. The concavities in the sacrificial layer yield convexities in the polysilicon layer to prevent stiction adhesion to the handle wafer. During processing, a mask used to pattern the membrane layer functions to protect an highly reflecting (HR) coating for the membrane.

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Bedford, MA, United States of America

Christopher C Cook