Method for fabricating of all-optical-fiber based optical polarizer devoid of fusing of first and second optical fibers. The method includes a process of forming a substantially adiabatic optical fiber taper by pulling an optical fiber and interrupting this process when an optical power parameter measured at an output of the optical fiber is reduced below a pre-defined threshold as a result of said pulling. An optically-tapered single-mode polarization-maintaining optical fiber element fabricated according to the method and configured as such all-optical-fiber polarizer.

An optical module having an externally-mounted magnetic ring and a chip positioning angle and a pressing block structure thereof are disclosed. The pressing block structure includes a pressing block. The pressing block includes a pressing block body. The pressing block body is provided with an insertion core positioning hole, a chip accommodating hole, and a magnetic ring accommodating chamber. The chip accommodating hole is provided with at least one positioning angle. The overall assembly accuracy of the optical module is improved, the material cost of the isolator chip is reduced, the positioning of the chip is more accurate, and the occurrence of glue overflow can be avoided.

A lidar system includes a laser diode to provide a frequency modulated continuous wave (FMCW) signal, and a current source to provide a drive signal that modulates the laser diode. The current source is controlled to pre-distort the drive signal to provide a linear FMCW signal. The lidar system also includes a splitter to split the FMCW signal into an output signal and a local oscillator (LO) signal, a transmit coupler to transmit the output signal, a receive coupler to obtain a received signal based on reflection of the output signal by a target, and a combiner to combine the received signal with the LO signal into first and second combined signals. A first and second photodetector respectively receive the first and second combined signals and output first and second electrical signals from which a beat signal that indicates the pre-distortion needed for the drive signal is obtained.

A lidar system includes a photonic chip including a light source and a transmit beam coupler to provide an output signal for transmission. The output signal is a frequency modulated continuous wave (FMCW) signal. A transmit beam steering device transmits the output signal from the transmit beam coupler of the photonic chip. A receive beam steering device obtains a reflection of the output signal by a target and provides the reflection as a received signal to a receive beam coupler of the photonic chip. The photonic chip, the transmit beam steering device, and the receive beam steering device are heterogeneously integrated into an optical engine.

An optical waveguide device includes a substrate on which an optical waveguide is formed, and a reinforcing block disposed on the substrate, along an end surface of the substrate on which an input portion or an output portion of the optical waveguide is disposed, in which an optical component that is joined to both the end surface of the substrate and an end surface of the reinforcing block is provided, a material used for a joining surface of the optical component and a material used for the substrate or the reinforcing block have at least different linear expansion coefficients of a direction parallel to the joining surface, and an area of a joining portion of the optical component is set to be smaller than an area of the end surfaces including joining portions of the substrate and the reinforcing block.

Apparatus for optically isolating a laser (1) from external reflections, which apparatus comprises a mode filter (19) and a first optical fibre (1), wherein: the first optical fibre (1) is a multimode optical fibre that supports a fundamental mode (3) and at least one higher order mode (4); the mode filter (19) is defined by an optical attenuation which is higher for the higher order mode (4) than for the fundamental mode (3); the mode filter (19) is configured to pass the fundamental mode (3) into the first optical fibre (1); and the apparatus being characterized in that: the first optical fibre (1) comprises a long period grating (10); and the long period grating (10) is defined by a period (13) selected to couple the fundamental mode (3) to the higher order mode (4) of the first optical fibre (1); whereby if the fundamental mode (3) and the higher order mode (4) are reflected back into the first optical fibre (1) as back-reflected fundamental and higher order modes (25), (26), then the mode filter (19) optically attenuates the back-reflected higher order mode (26) more than the back-reflected fundamental mode (25) thereby isolating the external reflection.

Reconfigurable non-reciprocal integrated-optics-based devices are disclosed. The non-reciprocal devices include: a phase-sensitive device, such as a microring waveguide; a magneto-optic layer; and an electromagnet. These elements are operatively coupled such that a magnetic field generated by current flow through the electromagnet gives rise to a non-reciprocal phase shift in the phase-sensitive device. The non-reciprocal phase shift leads to a difference in the way that a light signal travels in the forward and backward directions through one or more bus waveguides that are operatively coupled with the phase-sensitive element. The non-reciprocity is reversible by reversing the direction of drive current flow in the electromagnet, which enables the inter-port connectivity of the ports of these bus waveguides to be reconfigured based on the direction of the drive current flow. Examples of reconfigurable isolator and circulator embodiments are described.

An optical module includes a housing, at least one optical assembly and at least one sealing member. The housing includes a housing body, a cover and at least one vent hole therein. At least part of each optical assembly is located in the housing body. Each sealing member is located at a respective one of the at least one vent hole. The sealing member has a central axis and includes a first cylinder, a truncated cone, and a second cylinder, a diameter of the first cylinder is greater than a diameter of the second cylinder. Each vent hole is a stepped hole including a portion with a first aperture and a portion with a second aperture, the first aperture is greater than the second aperture. The first cylinder fits the portion with the first aperture, and the second cylinder fits the portion with the second aperture.

Apparatus for optically isolating a laser (1) from external reflections, which apparatus comprises a mode filter (19) and a first optical fibre (1), wherein: the first optical fibre (1) is a multimode optical fibre that supports a fundamental mode (3) and at least one higher order mode (4); the mode filter (19) is defined by an optical attenuation which is higher for the higher order mode (4) than for the fundamental mode (3); the mode filter (19) is configured to pass the fundamental mode (3) into the first optical fibre (1); and the apparatus being characterized in that: the first optical fibre (1) comprises a long period grating (10); and the long period grating (10) is defined by a period (13) selected to couple the fundamental mode (3) to the higher order mode (4) of the first optical fibre (1); whereby if the fundamental mode (3) and the higher order mode (4) are reflected back into the first optical fibre (1) as back-reflected fundamental and higher order modes (25), (26), then the mode filter (19) optically attenuates the back-reflected higher order mode (26) more than the back-reflected fundamental mode (25) thereby isolating the external reflection.

A chip-scale coherent lidar system includes a photonic chip that includes a light source, a transmit beam coupler to provide an output signal, and a receive beam coupler to receive a received signal based on a reflection of the output signal by a target. The system also includes a transmit beam steering device to transmit the output signal out of the system, and a receive beam steering device to obtain the received signal into the system. A transmit beam curved mirror reflects the output signal from the transmit beam coupler to the transmit beam steering device. A receive beam curved mirror reflects the received signal from the receive beam steering device to the receive beam coupler. The transmit beam curved mirror and the receive beam curved mirror are formed in a substrate that is heterogeneously integrated with the photonic chip.