Technologies for quantum sensing are disclosed. In the illustrative embodiment, a sensor system may be operated by coupling an electromagnetic wave from a measurement line to a first resonator. The sensor system includes a second resonator that is non-reciprocally coupled to the first resonator. In the absence or a perturbation, there is no reciprocal coupling between the first resonator and the second resonator, but a perturbation may cause reciprocal coupling between the first and second resonator. With appropriate selection of the non-reciprocal coupling, the signal at the output of the measurement line may allow for fast determination of whether the perturbation is present.

In one embodiment, a package includes: a substrate; a photonic integrated circuit (PIC) adapted to the substrate, the PIC including at least one optical circuit, a first plurality of waveguides, a second plurality of waveguides, and a laser to output optical energy via the first plurality of waveguides; and a prism assembly adapted to the substrate to reflect the optical energy output from the first plurality of waveguides to the second plurality of waveguides, the prism assembly including a prism and at least one isolator. Other embodiments are described and claimed.

In some implementations, an optical isolator core includes a Faraday rotator and a plurality of birefringent crystal plates. The plurality of birefringent crystal plates may include a first birefringent crystal plate to separate input light into light having a first polarization and light having a second polarization, and a second birefringent crystal plate to combine the light having the first polarization and the light having the second polarization in output light that is laterally displaced by the single stage optical isolator. The Faraday rotator may be provided between the first birefringent crystal plate and the second birefringent crystal plate. In some implementations, the plurality of birefringent crystal plates further include a third birefringent crystal plate provided between the Faraday rotator and the second birefringent crystal plate. Additionally, or alternatively, the optical isolator core may further include a half-wave plate arranged between the Faraday rotator and the first birefringent crystal plate.

A transmitter optical subassembly is disclosed including a substrate and a direct modulated laser disposed on the substrate. A single-stage isolator, a polarization direction rotator, and an optical branching filter are disposed side by side on the substrate in a light propagation direction. The polarization direction rotator can adjust linearly polarized light to P-polarized light, the optical branching filter includes an optical splitter subassembly and a filter subassembly, and an optical splitter film in the optical splitter subassembly is an optical splitter film with P polarization. The polarization direction rotator adjusts the incident linearly polarized light to the P-polarized light, and the optical splitter film in the optical branching filter is the optical splitter film with P polarization; all P-polarized light with single polarization can pass through the optical branching filter, without causing any polarization loss or two peaks.

The invention describes an apparatus that implements efficient coupling between a photonic integrated circuit (PIC) and a second optical element such as a fiber or laser, while at the same time allowing for efficient polarization management and/or optical isolation. It enables the packaging of PICs with large single mode fiber counts and in- and out-coupling of light with arbitrary polarization. The apparatus comprises a glass interposer that contains at least one polarization selective element together with a pair of lenses transforming a beam profile between the 2nd optical element and a polarization selective coupler on the PIC. The invention also comprises a method for fabricating the apparatus based on a subassembly of building blocks that are manufactured using wafer-scale high-precision glass-molding and surface treatment(s) such as thin-film coating.

An optical fiber filter has an ultra-wide tuning range and includes a two-dimensional mechanical rotating mirror, a collimating and beam expanding system, and two grating. An input fiber emits a multi-wavelength optical signal into the rotating mirror, which reflects the signal to the system to form collimated beams. In turn, the collimated beams are incident on the gratings that disperse the light of different wavelengths to different angles. Lights of different diffraction angles are input into an output fiber by adjusting the rotating mirror. The rotating mirror can be used to switch between gratings of different wavebands to tune optical wavelengths in an ultra-wide range.

An apparatus includes multiple dual cladding waveguides each having a single-mode interior section that transports one of multiple outgoing optical signals and a multimode section at least partially surrounding the interior section that transports one of multiple incoming optical signals. Different outgoing signals have different polarizations, and different incoming signals have different polarizations. The apparatus also includes a polarization beamsplitter that combines the multiple outgoing signals to produce transmit optical signals and separates receive optical signals to produce the multiple incoming signals.

A system includes an optical transceiver configured to transmit and receive optical signals. The optical transceiver includes a Faraday rotator and a waveplate. The Faraday rotator and the waveplate are collectively configured to provide a relative polarization change between (i) light propagating in a first direction through the Faraday rotator and the waveplate and (ii) light propagating in a second direction opposite the first direction through the Faraday rotator and the waveplate. The waveplate may include a quarter waveplate or a half waveplate.

An optical isolator has optical fibers arranged on a single side. The optical isolator includes an input optical fiber, an output optical fiber, an input splitting/combining device, an output splitting/combining device, an input optical rotation device, an output optical rotation device, a lens, a Faraday rotator, and a reflector. The input optical fiber and the output optical fiber are on a same side of each of the lens, the Faraday rotator, and the reflector. The optical isolator with input and output optical fibers arranged on a single side only needs to use one lens. The input and output splitting/combining devices are fixed on an end surfaces of input/output optical fibers, respectively.

The present disclosure provides an optical waveguide design of a fiber modified with a thin layer of epsilon-near-zero (ENZ) material. The design results in an excitation of a highly confined waveguide mode in the fiber near the wavelength where permittivity of thin layer approaches zero. Due to the high field confinement within thin layer, the ENZ mode can be characterized by a peak in modal loss of the hybrid waveguide. Results show that such in-fiber excitation of ENZ mode is due to the coupling of the guided fundamental core mode to the thin-film ENZ mode. The phase matching wavelength, where the coupling takes place, varies depending on the refractive index of the constituents. These ENZ nanostructured optical fibers have many potential applications, for example, in ENZ nonlinear and magneto-optics, as in-fiber wavelength-dependent filters, and as subwavelength fluid channel for optical and bio-photonic sensing.