Abstract:
A MOEMS Fabry-Perot tunable filter 100 includes an optical membrane structure 150. Two electrostatic cavities 136, 138 are provided, one on either side of the membrane structure 150. As a result, electrostatic attractive forces can be exerted on the optical membrane to enable deflection in either direction, typically, along the optical axis 10. This is useful in calibrating the tunable filter during operation to a lambd° set point. It is also useful in controlling the membrane to avoid unstable operation and increasing a deflection range.
Abstract:
A semiconductor optical amplifier system (100) comprises a hermetic package (112). In the typical implementation, this hermetic package (112) is a standard butterfly, DIP or miniDIL package. An optical bench (116) is sealed within this package (112). A first fiber pigtail (118) enters this package via a feed-through to connect to the bench (116) and terminate above the bench. A second optical fiber pigtail (120) enters the package (112) via a second fiber feed-through to connect to the bench (116) and similarly terminate above the bench. A semiconductor amplifier chip (102) is connected to the bench (116) to provide amplification. Isolators (128, 130) are further incorporated along with a monitoring diode (126) to yield a fully integrated system.
Abstract:
A wavelength measurement system uses birefringent material waveplate, thereby producing a substantially sinusoidal spectral response. As a result, the responses of multiple birefringent filters can be combined to yield a filter system with a periodic frequency response that has an additive wavelength resolution that is spectrally stable. That is, the wavelength measurement system (100) does not have regions where wavelength resolution is degraded. In one implementation, a waveplate system (112) is used, placed between two blocks of birefringent material (110) and (114). A quadrant detector (116) is used to detect the intensities of the resulting four beams.
Abstract:
A channel monitoring system has improved the spectral filtering accuracy by using a tunable filter system that transmits the optical signal through serial filter cavities. This has the effect of dramatically narrowing the filter's transfer function. Moreover, it improves side mode rejection. In the preferred embodiment, the filter is implemented in a double-pass configuration.
Abstract:
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.
Abstract:
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.
Abstract:
A semiconductor tunable laser system includes a tunable Fabry-Perot cavity and a cavity length modulator, which controls an optical length of the cavity at least over a distance corresponding to the spacings between the longitudinal modes of the laser cavity. Thus, the tunable Fabry-Perot cavity allows the laser cavity to have gain at the desired wavelength of operation while the cavity length modulator tunes the cavity length such that a longitudinal cavity mode exists at the desired wavelength of operation. Also, in one embodiment, a wavelength locker system is further provides that has a differential wavelength filter, e.g., stepped etalon, and a multi-element detector, e.g., a quad-detector. The controller then modulators the Fabry-Perot cavity to control the wavelength in response to the signal received from the multi-element detector.