Provided is a waveguide-type optical diffraction grating. A waveguide core includes a waveguide core that is asymmetric with respect to a thickness direction perpendicular to a light propagating direction. In the waveguide core, a phase adjustment portion is configured to adjust a phase difference between a forward wave traveling in an input direction and a reflected wave traveling in a direction reverse to the input direction in the waveguide-type optical diffraction grating, and the phase adjustment portion is provided in a manner that a sum of a phase of the forward wave and a phase of the reflected wave which are generated in the phase adjustment portion becomes a constant value irrespective of a polarization state of input light to the waveguide-type optical diffraction grating.

A tunable optical filter integrates the functions of wavelength tuning and power isolation of back reflection. The optical signal enters a Faraday rotator twice, and isolation is provided by two birefringent crystals, having their optical axes oriented at 45 degrees with respect to each other. The two birefringent crystals are on the same side of the Faraday rotator. The integration of an optical tunable filter and an isolator function into a single packaged component helps to reduce the size and complexity of optical amplifier systems, such as EDFAs and PDFAs, operating in the 1550 nm and 1310 nm transmission bands, respectively.

Methods and systems for a polarization immune wavelength division multiplexing demultiplexer are disclosed and may include, in an optoelectronic transceiver having an input coupler, a demultiplexer, and an amplitude scrambler: receiving input optical signals via the input coupler, communicating the input optical signals to the amplitude scrambler via waveguides, configuring the average optical power in each of the waveguides utilizing the amplitude scrambler, and demultiplexing the optical signals utilizing the demultiplexer. The amplitude scrambler may include phase modulators and a coupling section. The phase modulators may include sections of P-N junctions in the two waveguides. The demultiplexer may include a Mach-Zehnder Interferometer. The demultiplexed signals may be received utilizing photodetectors. The input coupler may include a polarization splitting grating coupler. The average optical power may be configured above which demultiplexer control circuitry is able to control the demultiplexer to process incoming optical signals.

The present invention provides an image sensor, including: a sensor array layer formed of a plurality of normal sensor units and a plurality of spectrometer sensor units; a first guided mode resonance (GMR) structure having a first grating pitch and disposed on the sensor array layer to cover N (where N is an integer) of the spectrometer sensor units; a second GMR structure having a second grating pitch and disposed on the sensor array layer to cover N of the spectrometer sensor units; and a plurality of color filter units disposed on the sensor array layer to cover the normal sensor units.

A wavelength demultiplexer is equipped with a spectroscopic means (which separates light that is input from multiple input light paths, and outputs the light to multiple output light paths) and a light path switching device (a device that switches the light paths that are input to the spectroscopic means, with the switching being performed by an external operation), and the light path switching device may be a device that distributes the input from one input port to multiple output ports. The light path switching device and the spectroscopic means are polarization-independent, with the input light paths, the output light paths, and the light paths between the light path switching device and the spectroscopic means being polarization-maintaining light paths, so the relative polarization configuration is the same for the input light and the output light.

Described herein is a multiplexer/demultiplexer optical device (100) comprising: a first beam-splitter cube (BS1); a second beam-splitter cube (BS2) optically coupled to the first splitter (BS1); a first Porro-prism reflector (PR1), which is optically coupled to the second splitter (BS2); and a second Porro-prism reflector (PR2), which is optically coupled to the second splitter (BS2) and is structured for introducing into optical beams that traverse it a phase delay depending upon an orbital angular momentum of the optical beams and upon an orientation of the second reflector. The device is a Michelson interferometer structured for obtaining constructive/destructive interference such as to multiplex/demultiplex on/from corresponding input/output ports, on the basis of values of orbital angular momentum, an optical beam comprising a plurality of concentric optical beams with cylindrical symmetry having different values of orbital angular momentum.

Provided is a waveguide-type optical diffraction grating. A waveguide core includes a waveguide core that is asymmetric with respect to a thickness direction perpendicular to a light propagating direction. In the waveguide core, a phase adjustment portion is configured to adjust a phase difference between a forward wave traveling in an input direction and a reflected wave traveling in a direction reverse to the input direction in the waveguide-type optical diffraction grating, and the phase adjustment portion is provided in a manner that a sum of a phase of the forward wave and a phase of the reflected wave which are generated in the phase adjustment portion becomes a constant value irrespective of a polarization state of input light to the waveguide-type optical diffraction grating.

The present invention relates to a wavelength division multiplexing optical receiver and eliminates excess loss of one polarization component while eliminating the need for a polarization-independent operation of a light receiver. An input waveguide, made of a silicon wire waveguide, is connected to a loop waveguide equipped with a polarization rotator over a polarization beam splitter. A ring waveguide equipped with an output waveguide configuring an add-drop ring resonator array is optically connected to the loop waveguide. The output light from ports at both sides of the output waveguide is incident onto first and second light-receiving surfaces of a light receiver such that the optical distances are equal to each other.

Methods and systems for a polarization immune wavelength division multiplexing demultiplexer are disclosed and may include, in an optoelectronic transceiver having an input coupler, a demultiplexer, and an amplitude scrambler: receiving input optical signals of different polarization via the input coupler, communicating the input optical signals to the amplitude scrambler via waveguides, configuring the average optical power in each of the waveguides utilizing the amplitude scrambler, and demultiplexing the optical signals utilizing the demultiplexer. The amplitude scrambler may include phase modulators and a coupling section. The phase modulators may include sections of P-N junctions in the two waveguides. The demultiplexer may include a Mach-Zehnder Interferometer. The demultiplexed signals may be received utilizing photodetectors. The input coupler may include a polarization splitting grating coupler. The average optical power may be configured above which demultiplexer control circuitry is able to control the demultiplexer to process incoming optical signals.