Abstract: The present invention provides a method and apparatus for optical spectral power monitoring that employ a time-division-multiplexed detection scheme. The optical spectral power monitoring apparatus of the present invention uses a wavelength-dispersing means such as a diffraction grating to separate a multi-wavelength optical signal into multiple spectral channels and an array of beam-manipulating elements positioned to correspond with the spectral channels. The beam-manipulating elements are individually controllable so as to direct the spectral channels into an optical detector in a time-division-multiplexed sequence. The optical spectral power monitoring apparatus may further employ a polarization diversity scheme, thereby becoming polarization insensitive. This enables the apparatus of the present invention to enhance spectral resolution, while providing improved accuracy in optical spectral power detection.

Abstract: This invention relates to an acousto-optical tunable filter generally of the kind described in U.S. Pat. No. 6,266,462. More specifically, the invention relates to a filter and its construction, the filter including a support, first and second mounts at spaced locations on the support, an optical fiber having first and second mounted portions secured to the first and second mounts respectively and a filtering section between the first and second mounted portions, a signal generator operable to generate a periodic signal, and an electro-acoustic transducer having a terminal connected to the signal generator and an actuating portion, the electric signal causing vibration of the actuating portion, and the actuating portion being connected to the filtering section so that the vibration generates a transverse wave traveling along the filtering section. The filter has an improved damper to more effectively dampen waves traveling along the filtering section.

Abstract: This invention provides a method and apparatus for spectral power monitoring by use of a polarization diversity scheme. In the present invention, a multi-wavelength optical signal is first decomposed into first and second polarization components, and the second polarization component is subsequently rotated by 90-degrees, prior to impinging onto a diffraction grating that provides a higher diffraction efficiency for the first polarization component. The diffraction grating separates the first and second polarization components by wavelength respectively into first and second sets of optical beams, impinging onto an array of optical power sensors. The inventive optical spectral power monitoring apparatus thus is able to minimize the insertion loss, while providing enhanced spectral resolution.

Abstract: This invention provides a novel wavelength-separating-routing (WSR) apparatus that uses a diffraction grating to separate a multi-wavelength optical signal by wavelength into multiple spectral channels, which are focused onto an array of corresponding channel micromirrors. The channel micromirrors are individually controllable and continuously pivotable to reflect the spectral channels into selected output ports. As such, the inventive WSR apparatus is capable of routing the spectral channels on a channel-by-channel basis and coupling any spectral channel into any one of the output ports. The WSR apparatus of the invention may further employ a polarization diversity scheme, whereby polarization-sensitive effects become inconsequential and insertion loss is minimized. The WSR apparatus of the invention may additionally be equipped with servo-control and channel equalization capabilities.

Abstract: The present invention provides a method and apparatus for optical spectral power monitoring employing novel frequency-division-multiplexing detection schemes. The optical spectral power monitoring apparatus of the present invention uses a wavelength-dispersing means (e.g., a diffraction grating) to separate a multi-wavelength optical signal into multiple spectral channels, and an array of beam-modulating elements (e.g., micromirrors) positioned such that each beam-modulating element receives a unique one of the spectral channels. The beam-modulating elements are individually controllable such that the optical power levels of the spectral channels coupled into an output port carry distinct dither modulation signals. By performing a synchronous detection of the dither modulation signals, in conjunction with a predetermined calibration table, an optical power spectrum of the multi-wavelength optical signal can be derived.

Abstract: This invention provides a novel method and apparatus which use a wavelength-dispersing means such as a diffraction grating to spatially separate a multi-wavelength optical signal along with a reference signal by wavelength into multiple spectral channels and a reference spectral component in a spectral array with a predetermined relative alignment. By aligning the reference spectral component at a predetermined location, the spectral channels simultaneously impinge onto designated locations, e.g., on an array of beam-receiving elements positioned in accordance with the spectral array. The reference spectral component may be further maintained at the predetermined location by way of servo-control, thereby ensuring that the spectral channels stay aligned at the designated locations. The present invention can be used to construct a new line of servo-based optical systems, including spectral power monitors and optical multiplexers/demultiplexers, for WDM optical networking applications.

Abstract: This invention provides a spectral power monitoring apparatus that uses a diffraction grating to separate a multi-wavelength optical signal along with a reference signal by wavelength into multiple spectral channels and a reference spectral component having a predetermined relative alignment, impinging onto an array of optical power sensors. The optical power sensor array may be configured such that the power levels of the spectral channels impinging onto the optical power sensor array can be related to the electrical signals thus produced by a predetermined conversion matrix. The spectral power monitoring apparatus of the present invention further includes an alignment compensation unit, which monitors the real-time impinging position of the reference spectral component and ensures that the corresponding conversion matrix is used for converting the measured electrical signals to the optical power levels of interest.

Abstract: This invention provides a novel wavelength-separating-routing (WSR) apparatus that uses a diffraction grating to separate a multi-wavelength optical signal by wavelength into multiple spectral channels, which are focused onto an array of corresponding channel micromirrors. The channel micromirrors are individually controllable and continuously pivotable to reflect the spectral channels into selected output ports. As such, the inventive WSR apparatus is capable of routing the spectral channels on a channel-by-channel basis and coupling any spectral channel into any one of the output ports. The WSR apparatus of the invention may further employ a polarization diversity scheme, whereby polarization-sensitive effects become inconsequential and insertion loss is minimized. The WSR apparatus of the invention may additionally be equipped with servo-control and channel equalization capabilities.

Abstract: This invention provides a novel wavelength-separating-routing (WSR) apparatus that uses a diffraction grating to separate a multi-wavelength optical signal by wavelength into multiple spectral channels, which are focused onto an array of corresponding channel micromirrors. The channel micromirrors are individually controllable and continuously pivotable to reflect the spectral channels into selected output ports. As such, the inventive WSR apparatus is capable of routing the spectral channels on a channel-by-channel basis and coupling any spectral channel into any one of the output ports. The WSR apparatus of the invention may further employ a polarization diversity scheme, whereby polarization-sensitive effects become inconsequential and insertion loss is minimized. The WSR apparatus of the invention may additionally be equipped with servo-control and channel equalization capabilities.

Abstract: This invention provides a novel wavelength-separating-routing (WSR) apparatus that uses a diffraction grating to separate a multi-wavelength optical signal by wavelength into multiple spectral channels, which are focused onto an array of corresponding channel micromirrors. The channel micromirrors are individually controllable and continuously pivotable to reflect the spectral channels into selected output ports. As such, the inventive WSR apparatus is capable of routing the spectral channels on a channel-by-channel basis and coupling any spectral channel into any one of the output ports. The WSR apparatus of the invention may further employ a polarization diversity scheme, whereby polarization-sensitive effects become inconsequential and insertion loss is minimized. The WSR apparatus of the invention may additionally be equipped with servo-control and channel equalization capabilities.