Described are various configurations of optical structures having asymmetric-width waveguides. A photodetector can include parallel waveguides that have different widths, which can be connected via passive waveguide. One or more light absorbing regions can be proximate to the waveguides to absorb light propagating through one or more of the parallel waveguides. Multiple photodetectors having asymmetric width waveguides can operate to transduce light in different modes in a polarization diversity optical receiver.

An optical interface assembly, comprising a lens, an optical receptacle, a stub disposed in the optical receptacle. The lens includes a convex surface farther away from the stub and a flat surface near the stub, the flat surface and a cross section of the lens being disposed at an inclined angle from each other. A first end surface of the stub facing the lens is disposed at an inclined angle relative to an axis of the stub. When a light beam is coupled into the stub by the lens, a portion of a return light reflected from the first end surface of the stub is reflected to an outside of the lens.

A cell site includes a tower, a multi-service terminal mounted to the tower and a base transceiver station in communication with the multi-service terminal. The multi-service terminal includes a housing and a plurality of adapters mounted to the housing. Each of the adapters includes an outer port accessible from outside the housing and an inner port accessible from inside the housing.

A laser module includes: an optical fiber; a plurality of semiconductor laser devices that includes a first semiconductor laser device and a second semiconductor laser device; a condenser lens that condenses laser beams emitted from the plurality of semiconductor laser devices and optically couples the laser beams to the optical fiber; a first terminal that supplies a first drive current to the first semiconductor laser device; and a second terminal that supplies a second drive current that to the second semiconductor laser device. The second drive current is smaller than the first drive current.

Described are various configurations of optical structures having asymmetric-width waveguides. A photodetector can include parallel waveguides that have different widths, which can be connected via passive waveguide. One or more light absorbing regions can be proximate to the waveguides to absorb light propagating through one or more of the parallel waveguides. Multiple photodetectors having asymmetric width waveguides can operate to transduce light in different modes in a polarization diversity optical receiver.

A laser assembly comprising a multi-clad fiber optically coupled to a light source configured to emit optical radiation at a first wavelength and a protective element disposed between the light source and the multi-clad fiber so as to prevent a portion of backward-propagating optical radiation at a second wavelength from coupling into the light source.

An optical interface assembly, comprising a lens barrel, a lens disposed in the lens barrel, an optical receptacle, a stub disposed in the optical receptacle, and a diaphragm disposed between the lens and the stub. A diameter of a light passing hole of the diaphragm is smaller than a diameter of a light passing surface of the lens. A first end surface of the stub facing the lens is disposed at an inclined angle relative to an axis of the stub. When a light beam is coupled into the stub by the lens, a portion of a return light reflected from the first end surface is reflected to an outside of the light passing hole of the diaphragm.

Improving the performance and efficiency of waveguide gratings while also improving the anti-reflection performance of the waveguide can be achieved by selective application of a dielectric anti-reflective coating (or coatings) to distinct regions of the waveguide. For example, a multi-layer dielectric anti-reflective coating is selectively applied to the region of the waveguide between an exit pupil expander grating and an outcoupler grating wherein light is transmitted within the waveguide via instances of total internal reflection (TIR) and where no gratings are typically present. By selectively excluding the regions of the waveguide containing gratings from receiving the anti-reflective coating, such as the incoupler and outcoupler regions, the performance of the gratings can be improved for their respective functions without compromising the anti-reflection performance of the waveguide overall.

A head-mounted display (HMD) system includes a micro-display configured to project light beams, each of light beams encompassing a range of wavelengths different from each of the other light beams, and a waveguide having multiple incouplers configured to receive and direct light into the waveguide. Each of the incouplers is a diffraction grating with a fill factor different from each of the other incouplers. In some embodiments, each of the incouplers has a different period value from each of the other incouplers and the period value of each of the incouplers is based on the range of wavelengths of light each of the incouplers is configured to receive.

A photonic integrated circuit. In some embodiments, the photonic integrated circuit includes: a waveguide; and a waveguide facet, a first end of the waveguide being at the waveguide facet, a first angle being an angle between: the waveguide at the first end of the waveguide and the normal to the waveguide facet, the first angle being at least 5 degrees, a first section of the waveguide having a first end at the waveguide facet and a second end, the first section having: a curvature of less than 0.01/mm at the first end of the first section, a curvature of less than 0.01/mm at the second end of the first section, and a curvature of at least 0.1/mm at a point between the first end and the second end.