An electro-optical chip includes an optical input port, an optical output port, and an optical waveguide having a first end optically connected to the optical input port and a second end optically connected to the optical output port. The optical waveguide includes one or more segments. Different segments of the optical waveguide extends in either a horizontal direction, a vertical direction, a direction between horizontal and vertical, or a curved direction. The electro-optical chip also includes a plurality of optical microring resonators is positioned along at least one segment of the optical waveguide. Each microring resonator of the plurality of optical microring resonators is optically coupled to a different location along the optical waveguide. The electro-optical chip also includes electronic circuitry for controlling a resonant wavelength of each microring resonator of the plurality of optical microring resonators.

An optical filter includes a first loop mirror, a second loop mirror, a first waveguide optically coupled to the first loop mirror and the second loop mirror, and a first access waveguide. The first loop mirror includes a first loop waveguide and a first multiplexer/demultiplexer. The second loop mirror includes a second loop waveguide and a second multiplexer/demultiplexer. The first loop waveguide is optically coupled to the first multiplexer/demultiplexer. The second loop waveguide is optically coupled to the second multiplexer/demultiplexer. The first waveguide is optically coupled to the first multiplexer/demultiplexer and the second multiplexer/demultiplexer. The first access waveguide is optically coupled to the first waveguide.

An electro-optic receiver includes a polarization splitter and rotator (PSR) that directs incoming light having a first polarization through a first end of an optical waveguide, and that rotates incoming light from a second polarization to the first polarization to create polarization-rotated light that is directed to a second end of the optical waveguide. The incoming light of the first polarization and the polarization-rotated light travel through the optical waveguide in opposite directions. A plurality of ring resonators is optically coupled the optical waveguide. Each ring resonator is configured to operate at a respective resonant wavelength, such that the incoming light of the first polarization having the respective resonant wavelength optically couples into said ring resonator in a first propagation direction, and such that the polarization-rotated light having the respective resonant wavelength optically couples into said ring resonator in a second propagation direction opposite the first propagation direction.

Techniques disclosed herein relate to photon sources with high spectral purity and high brightness. In one embodiment, a photon-pair source includes a pump waveguide, a first resonator coupled to the pump waveguide to couple pump photons from the pump waveguide into the first resonator, a second resonator coupled to the first resonator, and an output waveguide coupled to the second resonator. The second resonator is configured to convert the pump photons into photon pairs. The second resonator and the first resonator are configured to cause a coupling-induced resonance splitting in the second resonator or the first resonator. The second resonator and the output waveguide are configured to couple the photon pairs from the second resonator into the output waveguide. In some embodiments, the photo-pair source includes one or more tuners for tuning at least one of the first resonator or the second resonator.

A robust conjugate symmetric optical apparatus is disclosed. The robust conjugate symmetric optical apparatus comprises a first optical cell set and a second optical cell set. The first optical cell set includes a first plurality of cells, each of which includes a first left half cell and a first right half cell, and the respective first right half cell and the corresponding first left half cells form a first symmetric structure therebetween. The second optical cell set includes a second plurality of cells, each of which includes a second left half cell and a second right half cell, and the respective second right half cell and the corresponding second left half cells form a second symmetric structure therebetween, wherein each of the first left half cells of the first optical cell set and each of the second right half cells of the second optical cell set have the same structure; and each of the first right half cells of the first optical cell set and each of the second left half cells of the second optical cell set have the same structure.

An electro-optic combiner includes a polarization splitter and rotator (PSR) that directs a portion of incoming light having a first polarization through a first optical waveguide (OW). The PSR rotates a portion of the incoming light having a second polarization to the first polarization to provide polarization-rotated light. The PSR directs the polarization-rotated light through a second OW. Each of the first and second OW's has a respective combiner section. The first and second OW combiner sections extend parallel to each other and have opposite light propagation directions. A plurality of ring resonators is disposed between the combiner sections of the first and second OW's and within an evanescent optically coupling distance of both the first and second OW's. Each of ring resonators operates at a respective resonant wavelength to optically couple light from the combiner section of the first OW into the combiner section of the second OW.

Sensing apparatuses and method of making the sensing apparatuses are disclosed herein. In some variations, a sensing apparatus can comprise at least one optical waveguide, and at least one whispering gallery mode (WGM) resonator configured to propagate a set of WGMs, where the WGM resonator communicates to the at least one optical waveguide a set of signals corresponding to the set of WGMs. In some variations, a polymer structure may encapsulate the at least one WGM resonator and/or the at least one optical waveguide. Furthermore, in some variations, the WGM resonator(s) may have one or more selectable modes with different bandwidth and sensitivity for sensing, which may, for example, enable tailoring the sensing apparatus to specific applications having certain bandwidth and/or sensitivity requirements.

An integrated circuit includes an electronic circuit. The integrated circuit further includes a photonic device. The photonic device includes a first photodetector (PD) electrically connected to the electronic circuit. The photonic device further includes a second PD electrically connected to the electronic circuit. The photonic device further includes a first waveguide configured to receive an optical signal input, wherein the first waveguide is optically connected to the first PD. The photonic device further includes a second waveguide optically connected to the second PD. The photonic device further includes a resonant structure between the first waveguide and the second waveguide, wherein the resonant structure is configured to optically couple the first waveguide to the second waveguide.

An electro-optic combiner includes a polarization splitter and rotator (PSR) that directs a portion of incoming light having a first polarization through a first optical waveguide (OW). The PSR rotates a portion of the incoming light having a second polarization to the first polarization to provide polarization-rotated light. The PSR directs the polarization-rotated light through a second OW. Each of the first and second OW's has a respective combiner section. The first and second OW combiner sections extend parallel to each other and have opposite light propagation directions. A plurality of ring resonators is disposed between the combiner sections of the first and second OW's and within an evanescent optically coupling distance of both the first and second OW's. Each of ring resonators operates at a respective resonant wavelength to optically couple light from the combiner section of the first OW into the combiner section of the second OW.

Examples herein relate to optical systems. In particular, implementations herein relate to an optical system including an optical transmitter configured to transmit optical signals. The optical transmitter includes a first optical source coupled to an input waveguide and configured to emit light having different wavelengths through the input waveguide. The optical transmitter includes a Mach-Zehnder interferometer that includes a first arm and a second arm. The MZI further includes a first optical coupler configured to couple the emitted light from the input waveguide to the first and second arms and an array of two or more second optical sources coupled to the first arm. Each of the two or more second optical sources are configured to be injection locked to a different respective wavelength of the emitted light transmitted from the first optical source. The MZI further includes a second optical coupler configured to combine the emitted light from the first and second arms after propagating therethrough.