In an example, a photonic system includes a Si PIC with a Si substrate, a SiO.sub.2 box formed on the Si substrate, a first layer, and a second layer. The first layer is formed above the SiO.sub.2 box and includes a SiN waveguide with a coupler portion at a first end and a tapered end opposite the first end. The second layer is formed above the SiO.sub.2 box and vertically displaced above or below the first layer. The second layer includes a Si waveguide with a tapered end aligned in two orthogonal directions with the coupler portion of the SiN waveguide such that the tapered end of the Si waveguide overlaps in the two orthogonal directions and is parallel to the coupler portion of the SiN waveguide. The tapered end of the SiN waveguide is configured to be adiabatically coupled to a coupler portion of an interposer waveguide.

In an example, a photonic system includes a Si PIC-based polarization splitter rotator (PSR) that includes first and second SiN waveguides formed in a first layer of a Si PIC, each of the first and second SiN waveguides having a coupler portion. The PSR also includes a Si waveguide formed in a second layer of the Si PIC above or below the first layer. The Si waveguide includes a first tapered end near the coupler portion of the first SiN waveguide and adiabatically coupled to the coupler portion of the first SiN waveguide, a second tapered end near the coupler portion of the second SiN waveguide and adiabatically coupled to the coupler portion of the second SiN waveguide, and a first s-bend between the first and second tapered ends that cooperates with the first SiN waveguide to form a polarization rotator for light propagating in the first SiN waveguide.

A polarization converter based on taking a high-order TE mode as a transition mode comprises a ridge waveguide (1) and a slab waveguide (2) that are arranged in double layers and varying in width, and a strip waveguide (4) which is varying in width. The ridge waveguide (1) is disposed on the upper end face of the slab waveguide (2), and is aligned with two ends of the slab waveguide (2). The right end of the ridge waveguide (1) and the slab waveguide (2) are connected with the strip waveguide (4) with the varying width. A TM.sub.0 mode enters from the left ends of the ridge waveguide and the slab waveguide, and is converted into a TE.sub.0 mode for output. On the contrary, the TE.sub.0 mode enters from the right end of the strip waveguide and is converted into the TM.sub.0 mode for output.

This relates to a fiber-optic polarization orienting and filtering device including a first single-mode optical fiber, having a downstream end, and a polarizing optical fiber, having a first end and a second end, characterized in that the device further includes: a first rigid opto-mechanical linking region connecting the downstream end of the first single-mode optical fiber and the first end of the polarizing optical fiber along a first linking axis; and an orientation adjusting system, the system being suitable for adjusting the angular position of the first linking region about the first linking axis.

This patent document discloses, among others, wavelength-selective switches (WSS) for redirecting optical WDM signals or channels based on a combination of spatially separating light in different optical polarizations in an optical birefringent material and using diffractive optics for separating light at different optical WDM wavelengths into spatially separated optical beam to perform wavelength-selective optical switching in optical WDM applications. Notably, the optics for processing the optical WDM signals in the disclosed optical WSS devices is designed to provide scalable optical WSS devices where different WDM signals share optical components to reduce designed optical components for different WDM signals.

An apparatus of polarization self-compensated delay line interferometer. The apparatus includes a first waveguide arm of a first material of a first length disposed between an input coupler and an output coupler and a second waveguide arm of the first material of a second length different from the first length disposed between the same input coupler and the same output coupler. The apparatus produces an interference spectrum with multiple periodic passband peaks where certain TE (transverse electric) and TM (transverse magnetic) polarization mode passpand peaks are lined up. The apparatus further includes a section of waveguide of a birefringence material of a third length added to the second waveguide arm to induce a phase shift of the lined-up TE/TM passband peaks to a designated grid as corresponding polarization compensated channels of a wide optical band.

An apparatus of polarization self-compensated delay line interferometer. The apparatus includes a first waveguide arm of a first material of a first length disposed between an input coupler and an output coupler and a second waveguide arm of the first material of a second length different from the first length disposed between the same input coupler and the same output coupler. The apparatus produces an interference spectrum with multiple periodic passband peaks where certain TE (transverse electric) and TM (transverse magnetic) polarization mode passband peaks are lined up. The apparatus further includes a section of waveguide of a birefringence material of a third length added to the second waveguide arm to induce a phase shift of the lined-up TE/TM passband peaks to a designated grid as corresponding polarization compensated channels of a wide optical band.

A light polarisation converter for a photonic integrated circuit, comprising a first layer. The first layer comprises a first surface and a second surface. The second surface is offset from the first surface along a first axis and a second axis. The first axis is perpendicular to the first surface. The second axis is parallel to the first surface. The light polarisation converter comprises a second layer and a waveguide. The waveguide is between, and in contact with, the first layer and the second layer. The waveguide comprises a first waveguide portion in contact with the first surface, and a second waveguide portion in contact with the second surface. The second waveguide portion is offset from the first waveguide portion. The first waveguide portion has a first thickness different to a second thickness of the first waveguide portion. The first thickness and the second thickness are perpendicular the first surface.

A polarisation converter for a photonic integrated circuit. The polarisation converter comprises a first semiconductor layer, a second semiconductor layer and a third semiconductor layer. The second semiconductor layer comprises, when viewed in a cross-sectional plane perpendicular a light propagation axis, a first portion thicker than a second portion. The second semiconductor layer is between, and in contact with, the first semiconductor layer and the third semiconductor layer.

This patent document discloses, among others, wavelength-selective switches (WSS) for redirecting optical WDM signals or channels based on a combination of spatially separating light in different optical polarizations in an optical birefringent material and using diffractive optics for separating light at different optical WDM wavelengths into spatially separated optical beam to perform wavelength-selective optical switching in optical WDM applications. Notably, the optics for processing the optical WDM signals in the disclosed optical WSS devices is designed to provide scalable optical WSS devices where different WDM signals share optical components to reduce designed optical components for different WDM signals.