摘要:
A semiconductor light source comprises superluminescent diodes (SLDs) disposed on a substrate having a facet, channels separating the SLDs, and a mode expander region. Each SLD has a diamond shaped active region such that the front and rear end of each SLD ends in a taper. The mode expander region is disposed on at least one side of the tapers of the SLDs and is tapered into a waveguide extending to said facet.
摘要:
A system for measuring shoe length of a stylus adapted to track a path along a surface of a video disc comprises positioning the tip of the stylus adjacent the surface of a substrate having a signal therein for effecting capacitive variations between the stylus and the substrate, and measuring the capacitive variations between the stylus and the substrate while they are oriented in a first position to obtain a first signal. The stylus is then tilted an angle of .theta. degrees relative to the substrate, whereby the stylus and substrate are oriented in a second position relative to each other. The capacitive variations are measured while the stylus and substrate are oriented in the second position to obtain a second signal. The first signal is then compared with the second signal to obtain a difference signal proportional to the shoe length of the stylus.
摘要:
The fabrication of ultrasonic-wave lenses and prisms using low-surface tension (poor adhesion) polyalkene sheet (such as polyethylene) as an impedance-matching quarter-wave anti-reflective layer is made possible by the use of certain very low surface-tension cements.
摘要:
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.
摘要:
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.
摘要:
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. The device may be used to discriminate between finished surfaces and corroded surfaces, healthy and diseased tissue, and can sample the material or tissue in two or more areas. Versions of the invention include devices that are interferometers and or autocorrelators.
摘要:
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.
摘要:
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; and receiving the broadband light reflected from the biological sample by means of the sensing light path. The method also includes: directing the broadband light by means of the reference light path at a reflecting device; receiving the broadband light reflected from the reflecting device by means of the reference light path; and interfering the broadband light reflected from the biological sample and the broadband light reflected from the reflecting device. The method further includes: detecting the broadband light resulting from interference of the broadband light reflected from the biological sample and the broadband light reflected from the reflecting device; and modulating an effective light path length of at least one of the reference light path and the sensing light path to enhance interference of the broadband light reflected from the biological sample and the broadband light reflected from the reflecting device. The method continues with: determining a magnitude of change of the effective light path length introduced by the modulating when interference is enhanced; determining a variation in an index of refraction from a ratio of the magnitude of change of the effective light path length and the target depth; and determining the characteristic of the analyte in the biological sample from the variation in the index of refraction.
摘要:
An optical device (300) including first and second facets (340, 350); an at least partially bent waveguide (320) formed on a substrate and including a portion perpendicular to the first facet; and a light amplification region (310) coupled to the bent waveguide. The light amplification region includes an expanding tapered portion and a contracting tapered portion which approaches the second facet.
摘要:
Light emitting diodes each comprising a body of semiconductor material having a first side surface, a second side surface, and a top surface; and a stripe of conductive material over the top surface of the body. The stripe has a first segment and a second segment, each extending from the first side surface to the second side surface of the body. The first and second segments of the stripe are configured such that they are substantially non-parallel, and the width of the stripe at its ends is less than the width of the stripe intermediate its ends.