A multimode optical waveguide network comprises a parent waveguide and a plurality of child waveguides. Each waveguide is a multimode optical waveguide having a first surface region, multiple second surface regions, and at least one guiding element attached to a surface of the waveguide or embedded within the waveguide, each second surface region of the parent waveguide optically coupled to the first surface region of a corresponding child waveguide. The guiding element(s) of the parent waveguide is arranged to guide a beam, from or to its first surface region, to or from any selected second surface region of its multiple second surface regions. The guiding element(s) of each of the waveguides is configurable for selecting the second surface region of that waveguide and/or responsive to at least one beam characteristic for selecting the second surface region of that waveguide via modulation of the at least one beam characteristic.

A multimode optical waveguide network comprises a parent waveguide and a plurality of child waveguides. Each waveguide is a multimode optical waveguide having a first surface region, multiple second surface regions, and at least one guiding element attached to a surface of the waveguide or embedded within the waveguide, each second surface region of the parent waveguide optically coupled to the first surface region of a corresponding child waveguide. The guiding element(s) of the parent waveguide is arranged to guide a beam, from or to its first surface region, to or from any selected second surface region of its multiple second surface regions. The guiding element(s) of each of the waveguides is configurable for selecting the second surface region of that waveguide and/or responsive to at least one beam characteristic for selecting the second surface region of that waveguide via modulation of the at least one beam characteristic.

A method of performing a write operation in a holographic data storage system, in which schedule schedules at least one write operation across multiple non-contiguous write intervals, the write operation pertaining to a set of data to be stored in a region of a holographic recording medium. In each of the non-contiguous write intervals, the region of the holographic recording medium is exposed to an interference pattern caused by interference between a reference beam and an input beam carrying the set of data. The multiple non-contiguous write intervals have a total aggregate duration of sufficient length to cause a persistent state change in the exposed region, such that the set of data is recoverable from that region by the end of a final write interval of the multiple non-contiguous write intervals.

A method of performing a write operation in a holographic data storage system, in which schedule schedules at least one write operation across multiple non-contiguous write intervals, the write operation pertaining to a set of data to be stored in a region of a holographic recording medium. In each of the non-contiguous write intervals, the region of the holographic recording medium is exposed to an interference pattern caused by interference between a reference beam and an input beam carrying the set of data. The multiple non-contiguous write intervals have a total aggregate duration of sufficient length to cause a persistent state change in the exposed region, such that the set of data is recoverable from that region by the end of a final write interval of the multiple non-contiguous write intervals.

In an optical data transfer system, a beam modulator is configured to embed a set of data in an input beam. A multimode optical waveguide network has an in-coupling region for receiving the input beam. The multimode optical waveguide network is configured to guide the input beam to an out-coupling region of the multimode optical waveguide network. A spatial coherent detector is configured to measure a phase and an amplitude of an output optical field at multiple locations. The output optical field is at least partially defined by the input beam and thus exhibiting distortion effects caused by the passage of the beam through the multimode waveguide network. Signal processing is applied to an output of the spatial coherent detector, in order to compensate for the distortion effects, and thereby recover, from the output of the spatial coherent detector, the set of data embedded in the input beam.

In an optical data transfer system, a beam modulator is configured to embed a set of data in an input beam. A multimode optical waveguide network has an in-coupling region for receiving the input beam. The multimode optical waveguide network is configured to guide the input beam to an out-coupling region of the multimode optical waveguide network. A spatial coherent detector is configured to measure a phase and an amplitude of an output optical field at multiple locations. The output optical field is at least partially defined by the input beam and thus exhibiting distortion effects caused by the passage of the beam through the multimode waveguide network. Signal processing is applied to an output of the spatial coherent detector, in order to compensate for the distortion effects, and thereby recover, from the output of the spatial coherent detector, the set of data embedded in the input beam.

An optical path correction subassembly, an optical detection assembly, and an optical detection system are provided. The optical path correction subassembly can be optionally configured to be applied to a light detector. The optical path correction subassembly includes a holder structure and an optical path correction structure carried by the holder structure, and the optical path correction structure has a light beam guiding surface arranged as a reverse inclination inclined relative to a vertical line. The light beam guiding surface of the optical path correction structure can be configured to effectively or accurately guide a predetermined light beam to a light receiving surface of the light detector so as to facilitate collection of the predetermined light beam. The light beam guiding surface of the optical path correction structure can be arranged at an acute angle relative to the light receiving surface of the light detector.

An optical path correction subassembly, an optical detection assembly, and an optical detection system are provided. The optical path correction subassembly can be optionally configured to be applied to a light detector. The optical path correction subassembly includes a holder structure and an optical path correction structure carried by the holder structure, and the optical path correction structure has a light beam guiding surface arranged as a reverse inclination inclined relative to a vertical line. The light beam guiding surface of the optical path correction structure can be configured to effectively or accurately guide a predetermined light beam to a light receiving surface of the light detector so as to facilitate collection of the predetermined light beam. The light beam guiding surface of the optical path correction structure can be arranged at an acute angle relative to the light receiving surface of the light detector.

In a multilayer optical disc having information layers conforming to a plurality of different optical disc standards, because the type of each information layer is not recorded in the other information layers, in read and write operations by a compatible optical disc device conforming to a plurality of optical disc standards, every time the information layer being accessed changes, it has been necessary to read the type of the information layer and select a method of generating a tracking error signal adapted to the type of information layer, so access has taken time. In order to solve the above problem, in the optical multilayer disc according to the present invention, having information layers conforming to a plurality of different optical disc standards, in an area in one of the information layers, information about the other information layers is recorded. The time required to access the other information layers can be reduced by using this information to select a tracking error signal generating method.

Provided is a polarization state converting element including a plurality of waveplates, and a rotation mechanism that rotates the respective waveplates independently of one another around an optical axis. The waveplates are each configured by a substrate made of a material having no optical rotatory property but having birefringence, or are each made of a material having neither optical rotatory property nor birefringence, but having transparency, a function of phase delay depending on polarization being applied on a surface of each waveplate.