Structures for an optical power splitter and methods of forming a structure for an optical power splitter. A first waveguide core includes a portion positioned over a multimode interference region, a second waveguide core includes a portion positioned over the multimode interference region, and a third waveguide core includes a portion positioned over the multimode interference region. The first waveguide core provides an input port to the optical power splitter. The second waveguide core provides a first output port from the optical power splitter, and the third waveguide core provides a second output port from the optical power splitter.

Systems and methods described herein are directed to polarization separation of laser signals and/or incoming light signals associated with an imaging system, such as a Light Detection and Ranging (LIDAR) system. Example embodiments describe a system configured to direct incoming light signals to a polarization separator and capturing the two polarization states of the incoming light signals. In some instances, the laser signal may be converted into two different polarization states. The system may individually process the two polarization states of the incoming light signals along with the corresponding polarization state of the laser reference signal to extract information associated with reflecting objects within the field-of-view of the imaging system. The polarization separator may be a birefringent crystal positioned adjacent to an edge of a photonic integrated circuit (PIC) that is used for processing outgoing and incoming light signals associated with the imaging system.

A 90-degree optical hybrid includes two optical splitters that respectively split inputted light into two beams, two optical combiners that respectively combine two beams of inputted light and thereby output two beams of interfering light respectively, and four arm waveguides that input light splitted by any of the two optical splitters into any of the two optical combiners. Each of the four arm waveguides has a bend waveguide arranged at its center and a plurality of optical waveguides including a tapered waveguide having a width that decreases toward the bend waveguide. Both ends of each of the plurality of optical waveguides are respectively in contact with a end surface of any one of the two optical splitter, the two optical combiners, the bend waveguide and the other of the plurality of optical waveguides, and each of the plurality of waveguides is the tapered waveguide or a linear waveguide.

Structures for an optical power splitter and methods of forming a structure for an optical power splitter. A splitter body defines a multimode interference region of the optical power splitter. A first side element positioned adjacent to a first side surface of the splitter body, and a second side element positioned adjacent to a second side surface of the splitter body.

A photonic integrated circuit (PIC) includes various mode field adapters (MFAs), a waveguide, and various contact pads. All the MFAs are on a same facet of the PIC. One MFA of the PIC outputs a first optical signal that is an amplified version of a second optical signal. The waveguide is divided into two waveguide arms and a bend portion to join the two waveguide arms. The waveguide extends between the MFAs such that the second optical signal propagates through the waveguide. Further, each waveguide arm is formed between the contact pads. The second optical signal propagating through the waveguide is amplified based on a current that is injected in the PIC by way of the contact pads.

Embodiments include apparatuses, methods, and systems including a laser device having a 1×3 MMI coupler within a semiconductor layer. A front arm is coupled to the MMI coupler and terminated by a front reflector. In addition, a coarse tuning arm is coupled to the MMI coupler and terminated by a first back reflector for coarse wavelength tuning, a fine tuning arm is coupled to the MMI coupler and terminated by a second back reflector for fine wavelength tuning, and a SMSR and power tuning arm is coupled to the MMI coupler and terminated by a third back reflector. A gain region is above the front arm and above the semiconductor layer. Other embodiments may also be described and claimed.

To provide an optical element that can be more easily aligned with an optical fiber, an optical element includes one grating coupler optically coupled to an optical fiber, a waveguide connected to the grating coupler, a multimode interferometer connected to the waveguide on the opposite side to the grating coupler, and a waveguide inserted between two input/output ports on the branched side of the multimode interferometer.

The invention relates to an integrated polarisation splitter based on a sub-wavelength multimode interference coupler (110), in other words, a multimode interference coupler (110) with an anisotropic multimode waveguide region formed by a plurality of sections of core material (210) and a plurality of sections of a cladding material (230) alternately arranged in a periodic way, with a period (Λ) smaller than the wavelength of a light propagated through said anisotropic region. The core material sections (210) are rotated an angle (α) greater than zero with respect to a perpendicular with an input waveguide (120) to increase the anisotropic character of the multimode waveguide region.

This application provides an example light source switching apparatus. The apparatus includes first and second multi-mode interference (MMI) couplers, and a phase modulator. The first MMI coupler includes four ports, where first and second ports are located on one side, and third and fourth ports are located on the other side. The second MMI coupler includes three ports, where fifth and sixth ports are located on one side, and a seventh port is located on the other side. The first and the second ports connect to the fifth and the sixth ports, respectively, to form two connections. The phase modulator is disposed on one of the two connections, and the seventh port connects to an optical modulator. Both the third and the fourth ports connect to a light source emitting continuous light, and the phase modulator selects one of the two light sources for output from the seventh port.

An optical communication element includes a plurality of slabs, an input port group, an output port group, a first waveguide group, and a second waveguide group. The plurality of slabs includes third waveguide. Each of the plurality of slabs include a predetermined number of first ports being arranged at an inlet the third waveguide at equal intervals in a lateral direction perpendicular to a light traveling direction, and input the optical signals, and a predetermined number of second ports being arranged at an outlet of the third waveguide at the equal intervals in the lateral direction so as to face the first ports, and output the optical signals. Each of the third waveguides are configured with a dimension that allows light intensity to be distributed at all traveling positions located in the lateral direction.