Abstract: A new class of optical source having a truncated waveguide is provided, where a guided section of a light generating medium is terminated at an angle at a predetermined distance away from one end facet of the waveguide, thereby leaving a section for unguided light propagation. A truncated waveguide when implemented in combination with waveguide tilt, effective front facet reflectivity is reduced significantly to eliminate unwanted facet reflections. By extending electrical pumping in the unguided propagation section, the light in the unguided path propagates to a corresponding end facet without attenuation. The reflected light propagates freely without being intercepted by the waveguide. The principles are incorporated in different types of light generating and amplifying medium including a “double-pass” gain medium for designing optical sources having significantly high output power and negligibly small spectral modulation arising from unwanted facet reflections.

Abstract: A new class of optical source having a truncated waveguide is provided, where a guided section of a light generating medium is terminated at an angle at a predetermined distance away from one end facet of the waveguide, thereby leaving a section for unguided light propagation. A truncated waveguide when implemented in combination with waveguide tilt, effective front facet reflectivity is reduced significantly to eliminate unwanted facet reflections. By extending electrical pumping in the unguided propagation section, the light in the unguided path propagates to a corresponding end facet without attenuation. The reflected light propagates freely without being intercepted by the waveguide. The principles are incorporated in different types of light generating and amplifying medium including a “double-pass” gain medium for designing optical sources having significantly high output power and negligibly small spectral modulation arising from unwanted facet reflections.

Abstract: A new broadband source having a discrete set of spectral emission lines having high peak power in each line is provided by placing a gain medium in a reflective cavity comprising reflective front and back surfaces. A cavity feedback factor less than unity is achieved by providing reflectivity of one surface substantially lower than the reflectivity of the other surface such that spontaneous emission in the gain medium is linearly amplified just below the lasing threshold. In an alternative arrangement, a movable external back surface placed at a prescribed distance from the gain medium provides a means to achieve a free spectral range and finesse of the emission lines to match a pitch of a detector array in a SD-OCT system. By simultaneously providing high power to each detector element of the array, sensitivity and imaging speed of SD-OCT system are significantly improved.

Abstract: A new broadband discrete spectrum light source comprising a gain medium placed in a feedback cavity is disclosed. A design for a feedback cavity including reflectors having raised-edge reflectivity is presented. Bandwidth enhancement is achieved by selectively enhancing the intensity of the discrete emission lines near the band edges of the gain medium spectrum. The bandwidth of a broadband discrete spectrum light source is further enhanced by digitally applying a spectral correction to each detected signal according to a predetermined correction profile. A combined effect of using a broadband discrete spectrum light source and applying spectral correction to the detected signal in an imaging system such as a Spectral Domain Optical Coherence Tomography (SD-OCT) imaging system, results in a desired spectral profile and a bandwidth necessary to achieve higher depth resolution for obtaining high quality diagnostic images.

Abstract: A new broadband discrete spectrum light source comprising a gain medium placed in a feedback cavity is disclosed. A design for a feedback cavity including reflectors having raised-edge reflectivity is presented. Bandwidth enhancement is achieved by selectively enhancing the intensity of the discrete emission lines near the band edges of the gain medium spectrum. The bandwidth of a broadband discrete spectrum light source is further enhanced by digitally applying a spectral correction to each detected signal according to a predetermined correction profile. A combined effect of using a broadband discrete spectrum light source and applying spectral correction to the detected signal in an imaging system such as a Spectral Domain Optical Coherence Tomography (SD-OCT) imaging system, results in a desired spectral profile and a bandwidth necessary to achieve higher depth resolution for obtaining high quality diagnostic images.

Abstract: A new broadband source having a discrete set of spectral emission lines having high peak power in each line is provided by placing a gain medium in a reflective cavity comprising reflective front and back surfaces. A cavity feedback factor less than unity is achieved by providing reflectivity of one surface substantially lower than the reflectivity of the other surface such that spontaneous emission in the gain medium is linearly amplified just below the lasing threshold. In an alternative arrangement, a movable external back surface placed at a prescribed distance from the gain medium provides a means to achieve a free spectral range and finesse of the emission lines to match a pitch of a detector array in a SD-OCT system. By simultaneously providing high power to each detector element of the array, sensitivity and imaging speed of SD-OCT system are significantly improved.

Abstract: Interferometers and autocorrelator based sensors are disclosed that are configured to have multiple sample arms which can be scanned and the backscattered low coherence source light from a sample resolved in a single sweep of one or more variable delays of the sensor. Borescopes and catheters capable of scanning multiple sections or areas of materials and tissues using these sensors are described.

Abstract: Connectors and linking components for a guidewire probe having multiple optical emitting fibers and methods of making connectors and linking components for guidewire probes having multiple optical emitting fibers are described herein.

Abstract: A system and method which integrates a mirror at the fiber tip to the fiber tip and uses a tilted flat at the exit plane to prevent astigmatism caused by the cylindrical curvature of the fiber wall and minimize reflection.

Abstract: Interferometers and autocorrelator based sensors are disclosed that are configured to have multiple sample arms which can be scanned and the backscattered low coherence source light from a sample resolved in a single sweep of one or more variable delays of the sensor. Borescopes and catheters capable of scanning multiple sections or areas of materials and tissues using these sensors are described.

Abstract: A multi-channel low coherence interferometer having sensing and reference arms, at least one of which has variable delay. The sensing arm includes an optical switch for connecting to two or more probe arms. The distal ends of the probe arms collect source light backscattered from a sample. The backscattered light collected by the distal end of a probe arm is combined with reference light and a low coherence interferometric signal is produced by a sweep of a variable delay of the device or a sweep of a variable frequency laser light source. The interference signal produced by the interaction of reference and sensing light at a detector measures backscattered light, which may be used to characterize the sample. The low coherence interferometric signals can provide information about the morphology, physical nature, composition, and properties of the sample.

Abstract: A method for diagnosing a human condition from a characteristic of a plaque or tissue in a subject is presented. The method includes directing broadband light by means of a sensing light path at an area of interest in the subject, at a target depth defined by the sensing light path and a reference light path. The continues with receiving the broadband light reflected from the area of interest in the subject by means of the sensing light path. The method further includes directing the broadband light by means of the reference light path at a reflecting device, and receiving the broadband light reflected from the reflecting device by means of the reference light path.

Abstract: Connectors and linking components for a guidewire probe having multiple optical emitting fibers and methods of making connectors and linking components for guidewire probes having multiple optical emitting fibers are described herein.

Abstract: Interferometers and autocorrelator based sensors are disclosed that are configured to have multiple sample arms which can be scanned and the backscattered low coherence source light from a sample resolved in a single sweep of one or more variable delays of the sensor. Borescopes and catheters capable of scanning multiple sections or areas of materials and tissues using these sensors are described.

Abstract: The invention relates to a system, method and device for optically determining the shape and size of a lumen of a vessel or body cavity, and of, for example, a balloon stent as it is inflated. The size and shape determination of the lumen of the vessel or body cavity allows for accurate and safe deployment of a stent within the lumen.

Abstract: A method for determining a characteristic of an analyte in a biological sample, the method comprising: directing broadband light by means of a sensing light path at the biological sample, at a target depth defined by the sensing light path and a reference light path; receiving the broadband light reflected from the biological sample by means of the sensing light path; directing the broadband light by means of the reference light path at a fixed reflecting device; and receiving the broadband light reflected from the fixed reflecting device by means of the reference light path.

Abstract: A system and method which integrates a mirror at the fiber tip to the fiber tip and uses a tilted flat at the exit plane to prevent astigmatism caused by the cylindrical curvature of the fiber wall and minimize reflection.

Abstract: A multi-channel low coherence interferometer having sensing and reference arms, at least one of which has variable delay. The sensing arm includes an optical switch for connecting to two or more probe arms. The distal ends of the probe arms collect source light backscattered from a sample. The backscattered light collected by the distal end of a probe arm is combined with reference light and a low coherence interferometric signal is produced by a sweep of a variable delay of the device or a sweep of a variable frequency laser light source. The interference signal produced by the interaction of reference and sensing light at a detector measures backscattered light, which may be used to characterize the sample. The low coherence interferometric signals can provide information about the morphology, physical nature, composition, and properties of the sample.

Abstract: A probe for use in characterizing tissue. The probe includes a plurality of optical fibers and an optical element. Each fiber includes a distal portion and a proximal portion. The fibers transmit light through the fiber to a surrounding area and collect light reflected back from the surrounding area. The optical element may be adjacent an outer periphery of the distal portion of the plurality of optical fibers. The optical element reduces an optical path length through blood.

Abstract: A method for determining a characteristic of tissue in a biological sample comprising: directing light at the biological sample at a first depth and receiving that light reflected from the biological; directing the light at a reflecting device and receiving that light reflected from the reflecting device. The method also includes: interfering the light reflected from the biological sample and the light reflected from the reflecting device; detecting light resulting from the interfering; and determining a first phase associated with the light resulting from the interfering based on the first depth. The method further includes: varying an effective light path length to define a second depth; determining a second phase associated with the light resulting from the interfering based on the second depth; and determining the characteristic of the biological sample from the first phase and the second phase.