A silicon photonic package structure including a substrate, a conductive bump, an obstacle structure, a laser diode, a mode converter, and a ball lens is provided. The conductive bump is disposed on the substrate. The obstacle structure is formed on the substrate. The laser diode is disposed above the substrate and electrically bonded to the conductive bump. A surface of the laser diode facing the substrate has a ridge. An end of the ridge has a light-emitting surface. The obstacle structure is located between the conductive bump and the ridge. A thickness of the obstacle structure in a direction perpendicular to the surface of the substrate is greater than a thickness of the ridge in the direction perpendicular to the surface of the substrate. The mode converter is formed on the substrate. The ball lens is formed on the substrate and located between the light-emitting surface and a light input end of the mode converter.

A light detection and ranging (LiDAR) system according to the present disclosure comprises an optical source to emit an optical beam. The LiDAR system comprises a PSR comprising a silicon nitride based waveguide to split and rotate a target return signal of the optical beam from a target. The silicon nitride based waveguide includes a first silicon nitride segment and a second silicon nitride segment. The first silicon nitride segment includes a first layer and a second layer. The first silicon nitride segment has tapered widths along a longitudinal direction. The second silicon nitride segment includes a silicon nitride adiabatic coupler. The LiDAR system further comprises an optical element to generate a local oscillator (LO) signal and a PD to mix the target return signal with the LO signal to generate a heterodyne signal to extract information of the target.

According to various aspects of the present disclosure, an apparatus is provided. In an aspect, the apparatus includes an optical transceiver having a first port, a second port and an optical switch coupled to the first port and the second port. The optical switch is switchable between a unidirectional port operation mode and a bidirectional port operation mode. When the optical switch is in the unidirectional port operation mode, the first port is configured to send a first optical signal, and the second port configured to receive a second optical signal. When the optical switch is in the bidirectional port operation mode, the first port configured to send the first optical signal and receive the second optical signal, and the second port configured to receive a third optical signal and not send the first signal. Furthermore, a second bidirectional port operation mode is supported with the second port configured to send the first optical signal and receive the second optical signal, and the first port configured to receive a third optical signal and not send the first signal.

A device providing efficient transformation between an initial optical mode and a second optical mode includes first, second and third elements fabricated on a common substrate. The first element includes first and second active sub-layers supporting initial and final optical modes with efficient mode transformation therebetween. The second element includes a passive waveguide structure supporting a second optical mode. The third element, at least partly butt-coupled to the first element, includes an intermediate waveguide structure supporting an intermediate optical mode. If the final optical mode differs from the second optical mode by more than a predetermined amount, a tapered waveguide structure in the second or third elements facilitates efficient transformation between the intermediate optical mode and the second optical mode. Precise alignment of sub-elements formed in one of the elements, relative to sub-elements formed in another one of the elements, is defined using lithographic alignment marks.

A mode multiplexing/demultiplexing optical circuit with a reduced inter-mode crosstalk is provided. A mode multiplexing/demultiplexing optical circuit includes a Port 1 through which light from a light source is input to a waveguide, a Port 3 through which light propagating through a first waveguide is output, a mode conversion unit located adjacent to the first waveguide, and configured to convert a first-order mode light input from the Port 3 to a second-order mode, and Port 2 configured to convert, via a waveguide located adjacent to the mode conversion unit, second-order mode light input to the mode conversion unit to a zeroth-order mode.

A LiDAR system includes an optical source to emit an optical beam and a PSR a silicon nitride based waveguide to split and rotate an optical beam. The silicon nitride based waveguide includes a first silicon nitride segment including a first layer and a second layer, the first silicon nitride segment having tapered widths along a longitudinal direction. The second layer includes a first section extending from a first end of the first silicon nitride segment to a converging plane with increasing widths and a second section extending from the converging plane to a second end of the first silicon nitride segment with decreasing widths. The LIDAR system further includes an optical element to generate a local oscillator (LO) signal and an optical detector to mix the target return signal with the LO signal to generate a heterodyne signal to extract range and velocity information of the target.

A method of fabricating a waveguide mode expander includes providing a substrate including a waveguide, bonding a chiplet including multiple optical material layers in a mounting region adjacent an output end of the waveguide, and selectively removing portions of the chiplet to form tapered stages that successively increase in number and lateral size from a proximal end to a distal end of the chiplet. The first optical material layer supports an input mode substantially the same size as a mode exiting the waveguide. One or more of the overlying layers, when combined with the first layer, support a larger, output optical mode size. Each tapered stage of the mode expander is formed of a portion of a respective layer of the chiplet. The first layer and the tapered stages form a waveguide mode expander that expands an optical mode of light traversing the chiplet.

One illustrative TE pass polarizer disclosed herein includes an input/output layer, a first buffer layer positioned above at least a portion of the input/output layer, a layer of epsilon-near-zero (ENZ) material positioned above at least a portion of the first buffer layer, and a metal-containing capping layer positioned above at least a portion of the layer of ENZ material.

In conventional hybrid lasers large back refection may lead to a degradation of relative intensity noise (RIN), linewidth broadening, mode hopping, etc. To solve the aforementioned problem a hybrid laser includes a mode converter for converting a higher-back-reflection mode of the light to a mode providing less back reflection to the gain chip. The mode converter may comprise a polarization rotator, a waveguide converter, or high-order mode converter. A routing waveguide may be provided including a phase shifter, e.g. a doped waveguide, for adjusting a cavity length of the laser cavity.

One illustrative TE pass polarizer disclosed herein includes an input/output layer, a first buffer layer positioned above at least a portion of the input/output layer, a layer of epsilon-near-zero (ENZ) material positioned above at least a portion of the first buffer layer, and a metal-containing capping layer positioned above at least a portion of the layer of ENZ material.