Abstract: A method of making an optical device to wavelength multiplex/de-multiplex light signals by altering the refractive index of regions within a material is disclosed. A substrate is formed from a material having a refractive index that can be altered by a process. At least one region within the substrate is subjected to the process, thereby altering the refractive index of the substrate within that region. An optical component of the multiplexer/de-multiplexer is formed by or includes the altered region. Also disclosed is an optical multiplexer/de-multiplexer device that includes an optical component that includes a region within a substrate, in which the region has an altered refractive index.

Abstract: An optical diffraction grating includes a substrate and a diffraction surface comprising, for example, diffraction grooves. The diffraction grating has a spatially varying diffraction efficiency which increases or decreases as a function of distance from a reference location at which an incident light beam is received at the grating. Spatially varying the diffraction efficiency of the grating may be accomplished by selectively changing or modifying one or more grating design parameters such as the shape, size, depth, profile, pitch, and optical properties of the diffraction grooves at predetermined locations on the grating.

Abstract: Devices and methods for processing multi-wavelength light beams and the single-wavelength components of such light beams are disclosed. In accordance with some embodiments, a spectral filter includes collimating and focusing optical elements, an apodizing filter, a diffraction grating, and a spatial filter. The collimating optical element collimates an input light beam while the apodizing filter spatially filters this beam. In general, the apodizing filter includes a range of transmissivity that varies according to a distance from a predetermined location on the apodizing filter. The diffraction grating diffracts the input beam which is focused by the focusing optical element onto the spatial filter to generate a filtered output beam. Embodiments of the invention may be employed as spectral filters, optical spectrum analyzers, optical mutiplexers, optical de-multiplexers, and the like.

Abstract: An apparatus for optically shifting the frequency of an input signal beam includes a first Raman medium that receives an input signal beam, a first pump beam, and a first reference beam to responsively generate an intermediate signal beam comprising a Raman sideband of the first Raman medium. A second Raman medium is optically coupled in series with the first Raman medium. The second Raman medium receives the intermediate signal beam, a second pump beam, and a second reference beam to responsively generate an output signal beam comprising a Raman sideband of the second Raman medium. The generated output signal represents the input signal that is shifted in frequency by a frequency shift that corresponds to the frequency difference between the first and second reference beams.

Abstract: Systems and methods for making a self-aligning optical system are provided, Briefly described, in architecture, one such system for making an optical system, among others, can be implemented as follows. The system comprises a grating substrate supporting a holographically-formed diffraction grating and an array mount for defining relative locations of point sources of light. The array mount comprises recording points that define locations of point sources of recording light used to illuminate the grating substrate during fabrication of the holographically-formed diffraction grating and use points that define locations of light apertures used in operation of the holographically-formed diffraction grating. Other systems and methods are also provided.

Abstract: Wavelength spread-spectrum coding enables a multi-channel communication systems to transmit more information signals than the number of transmission channels. At the transmitter, each information signal is encoded with a respective spreading code to generate a coded signal corresponding to each bit of the spreading code and the coded signals corresponding to the same bit of the spreading codes are allocated to a respective transmission channel. Then, in each transmission channel, the coded signals allocated thereto are analog summed to generate a modulation signal, and a transmission signal is modulated in response to the modulation signal. In the receiver, each information signal is recovered by multiplying the channel signal from each transmission channel by a respective bit of the spreading code assigned to the information signal to generate a respective product signal, summing the product signals to generate a sum signal, and subjecting the sum signal to thresholding.

Abstract: An optical communication network in which interoperable optical frequency channels are defined without an absolute frequency reference. In accordance with a first embodiment, non-absolute frequency references identical in frequency are provided to the nodes on the network. At each node, one of the channels of a tunable multi-channel device located at the node is frequency aligned with the non-absolute frequency reference. Once the tunable multi-channel devices have been frequency aligned with the non-absolute frequency reference, respective transceivers located at the respective nodes are frequency aligned to different ones of the channels of the tunable multi-channel device so that they can transmit and receive optical information signals at frequencies defined by the tunable multi-channel device.

Abstract: The optical WG device comprises two optical WGs and an optical coupler extending between the adjacent ends of the WGs. The optical coupler comprises material that includes a waveguide region. The waveguide region has a shape defined by overlapping cones of light emitted from the ends of the optical waveguides. In the optical alignment method, first and second optical waveguides are axially aligned, leaving a gap between their adjacent ends. The gap is filled with material having a refractive index capable of being increased by exposing the material to light. The material is exposed to conical beams of light emitted from the adjacent ends of the waveguides. Exposing the material increases the refractive index of the material in a region in which the beams of light overlap. The resulting refractive index difference prevents light from diverging as it propagating across the gap between adjacent ends of the optical waveguides.