A LIDAR system includes a light source configured to output a source signal. The LIDAR chip is also configured to output a LIDAR output signal that exits from the LIDAR chip. The LIDAR system also includes an isolator adapter that includes an optical isolator configured to receive an adapter signal. The adapter signal includes light that is from the source signal and that has exited from the LIDAR chip before being received by the optical isolator. The isolator is configured to output light from the adapter signal in an isolator output signal. Additionally, the LIDAR output signal includes light from the isolator output signal.

Technologies for coupling to and from a photonic integrated circuit (PIC) with an optical isolator are disclosed. In one embodiment, light beams from waveguides on a PIC die are reflected towards flat mirrors on the bottom surface of the PIC die. The flat mirrors reflect the light towards curved mirrors defined in a top surface of the PIC die, which collimate the beam and direct the collimated beams out the bottom surface of the PIC die. An optical isolator below the PIC die can allow the beams to pass while blocking beams in the opposite direction.

An optical circulator is a device that routes optical pulses from port to port in a predetermined manner, e.g. in a 3-port optical circulator, optical pulses entering port 1 are routed out of port 2, while optical pulses entering port 2 exit out of port 3 and optical pulses fed into port 3 exit out of port 3. Currently such an optical circulator is made of discrete components such as magnetooptic garnets, rare-earth magnets and optical polarizers that are packaged together with fiber optic elements. Disclosed herein is a different kind of optical circulator that is monolithically integrated on a single semiconductor substrate and that is applicable for the routing of optical pulses. The embodied invention will enable photonic integrated circuits to incorporate on-chip optical circulator functionality thereby allowing much more complex optical designs to be implemented monolithically.

A simple, compact and low-cost passive optical transceiver device with four terminals may be used in an optical transmission system with polarization-diversity coherent detection scheme. The transceiver is composed of a first polarization splitter/combiner, a non-reciprocal polarization rotator and a second polarization splitter/combiner. The device simultaneously operates as a transmitter and a receiver with optical signals propagating along opposite directions wherein non-reciprocal polarization rotation leads to distinct effects. The received optical signal is thus split into two orthogonal polarization components directed towards two separate ports.

An optical coupling device can include a first birefringent layer having opposing first and second surfaces. The first birefringent layer can split incident light received at the first surface into first and second beams. The first and second beams can have respective polarization orientations that are orthogonal to each other. The first birefringent layer can propagate the first and second beams along respective first and second paths within the first birefringent layer to the second surface. The first and second beams can be spatially separated at the second surface. A redirection layer facing the second surface of the first birefringent layer can include first and second grating couplers configured to respectively redirect the first and second beams to propagate within the redirection layer as respective third and fourth beams. In some examples, the third and fourth beams can have respective polarization orientations that are parallel to each other.

The present disclosure relates to system-level integration of lasers, electronics, integrated photonics-based optical components and a rotation sensing element, which can be a fiber coil or a sensing coil/micro-resonator ring on a sensing chip. Novel waveguide design on the integrated photonics chip, acting as a front-end chip, ensures precise detection of phase change in the fiber coil or the sensing chip, where the sending chip is coupled to the front end chip. Electrical and/or thermal phase modulators are integrated with the integrated photonics chip. Additionally, implant regions are introduced around the waveguides and other optical components to block unwanted/stray light into the waveguides and optical signal leaking out of the waveguide.

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.

Nonreciprocal optical transmission devices and optical apparatuses including the nonreciprocal optical transmission devices are provided. A nonreciprocal optical transmission device includes an optical input portion, an optical output portion, and an intermediate connecting portion interposed between the optical input portion and the optical output portion, and comprising optical waveguides. A complex refractive index of any one or any combination of the optical waveguides changes between the optical input portion and the optical output portion, and a transmission direction of light through the nonreciprocal optical transmission device is controlled by a change in the complex refractive index.

An optical isolator for use with high power, collimated laser radiation includes an input polarizing optical element, at least one Faraday optical element, at least two reflective optical elements for reflecting laser radiation to provide an even number of passes through said at least one Faraday optical element, at least one reciprocal polarization altering optical element, an output polarizing optical element, at least one light redirecting element for remotely dissipating isolated or lost laser radiation. The isolator also includes at least one magnetic structure capable of generating a uniform magnetic field within the Faraday optical element which is aligned to the path of the collimated laser radiation and a mechanical structure for holding said optical elements to provide thermal gradients that are aligned to the path of the collimated laser radiation and that provide thermal and mechanical isolation between the magnetic structure and the optical elements.

An avionics unit for an avionics network is disclosed having a light emitter to provide a modulated broadband optical signal. The avionics unit also includes a first optical interface and a second optical interface. The first optical interface is optically connected to the light emitter and is to receive a removable wavelength selective filter to extract a modulated narrowband optical signal from the modulated broadband optical signal. The second optical interface is optically connected to the first optical interface and is to output the modulated narrowband optical signal.