Abstract: A compact interrogator for the simultaneous interrogation of multi wavelength-modulated fiber optical sensors, includes a planar waveguide based demultiplexer receiving input signals from the sensors. An array of detectors is coupled to output waveguides of the demultiplexer corresponding to different nominal wavelengths. A tuning element matches the nominal wavelengths of the output waveguide to the input signals from the respective sensors to find the wavelengths of the individual sensors to be interrogated.

Abstract: A method of extracting a tomographic image of a layer within a body by optical coherence tomography, involves capturing three images, namely a non-interference background image, a first interference-fringe image of said layer, and a second interference-fringe image phase-shifted relative to the first interference-fringe image. The tomographic image is obtained by mathematically combining the three captured images. In a preferred embodiment random noise is removed by averaging and inter-layer effects are removed by applying a compensation function. This system is then used to extract the 2D cross-sectional images encoded in a multiple-layer information carrier.

Abstract: In a method of coding and retrieving information by using the unique emission properties of the semiconductor nanocrystals (quantum dots) for the identification of valuable documents, articles and objects, a carrier medium is prepared containing quantum dots selected to give the carrier medium defined fluorescent emission characteristics encoding predetermined information. The carrier medium is then applied to the object, preferably in the form of an ink.

Abstract: Polarization-mode dispersion (PMD) of an optical device, i.e. fiber or component is effected by launching a first pump laser beam of a fixed wavelength, a probe laser beam with a second fixed wavelength and a second pump laser beam having a variable wavelength and a polarization direction orthogonal to the other two beams into an optical device to generate three output signals which are input into a semiconductor optical amplifier to generate four-wave mixing (FWM) products. The average PMD of the device is computed by measuring the power of the FWM products versus the wavelength of the second pump laser beam.

Abstract: An integrated optical dynamic channel equalizer that can be employed to equalize the channel gain level in a WDM transmission line and monitor the optical channel performance. The device consists of a circulator, a dynamic gain equalizer chip and a controller. Due to the simplicity of the dynamic gain equalizer chip, which includes one 1×n multiplexer/demultiplexer, an n-channel variable optical attenuator array (VOA-n), a partially transparent dielectric reflective means and an n-channel detector array, the device is very compact and can be fabricated at low cost. By placing a quarter wave plate between the n-channel variable optical attenuator array and the partially transparent reflective means in the dynamic channel equalizer chip, the device can be rendered polarization insensitive.

Abstract: A method of extracting a tomographic image of a layer within a body by optical coherence tomography, involves capturing three images, namely a non-interference background image, a first interference-fringe image of said layer, and a second interference-fringe image phase-shifted relative to the first interference-fringe image. The tomographic image is obtained by mathematically combining the three captured images. In a preferred embodiment random noise is removed by averaging and inter-layer effects are removed by applying a compensation function. This system is then used to extract the 2D cross-sectional images encoded in a multiple-layer information carrier.

Abstract: Methods of coding and retrieving information by using the unique emission properties of the semiconductor nanocrystals (quantum dots) for the identification of valuable documents, articles and objects are described. A carrier medium is prepared containing quantum dots selected to give the carrier medium defined fluorescent emission characteristics encoding predetermined information. The carrier medium is then applied to the object, preferably in the form of an ink.

Abstract: An integrated optical dynamic channel equalizer that can be employed to equalize the channel gain level in a WDM transmission line and monitor the optical channel performance. The device consists of a circulator, a dynamic gain equalizer chip and a controller. Due to the simplicity of the dynamic gain equalizer chip, which includes one 1×n multiplexer/demultiplexer, an n-channel variable optical attenuator array (VOA-n), a partially transparent dielectric reflective means and an n-channel detector array, the device is very compact and can be fabricated at low cost. By placing a quarter wave plate between the n-channel variable optical attenuator array and the partially transparent reflective means in the dynamic channel equalizer chip, the device can be rendered polarization insensitive.