A pluggable miniature optical passive device comprises a casing (30), an optical device (40) is mounted in the casing (30), a first end of the optical device (40) is provided with a first ceramic ferrule (43). At least one fiber core (432) is provided in the first ceramic ferrule (43), a first end (41) of the first ceramic ferrule (43) extends out of the casing (30). A second end (42) of the first ceramic ferrule (43) is positioned in the optical device (40), and the second end (42) of the first ceramic ferrule (43) is coated with an antireflection film, a lens (45) is provided close to the second end (42) of the first ceramic ferrule (43), the lens (45) is positioned in the optical device (40). At least one optical fiber is further provided in the optical device (40), a first end of the optical fiber is provided at a side close to the lens (45) and away from the first ceramic ferrule (43), a light beam incident in the optical fiber of the optical device (40) via the ceramic ferrule (43) and the lens (45). The pluggable miniature optical passive device has a small volume, and low manufacturing cost and long service life.

For imaging objects in a field-of-view, a compound lens includes a primary lens, a secondary lens, and a tertiary lens. A combination of the primary lens, the secondary lens, and the tertiary lens has an F-number of not more than 1.25, a field-of-view of at least 70 degrees, and images objects from the field-of-view on a sensor.

Embodiments of present invention provide an ultra-small-pitch optical filter assembly. The assembly includes a fiber collimator being able to receive an optical signal; a WDM filter module being able to de-multiplex the optical signal from the fiber collimator into multiple optical beams; and an optical lens assembly being able to receive the multiple optical beams from the WDM filter module and to reduce a physical spacing among the multiple optical beams from a first pitch D to a second pitch d, wherein D/d A method of fabricating the ultra-small-pitch optical filter assembly is also provided. A method of producing a set of optical beams with ultra-small-pitch of spacing is provided as well.

Disclosed is a compact device for wavelength-division multiplexing applications. In particular, disclosed is a device that includes a housing and a core at least partially positioned within the housing. The core includes a first single fiber stub, a second single fiber stub, and at least one functional layer positioned between a first fiber of the first single fiber stub and a second fiber of the second single fiber stub. The at least one functional layer is configured to: (i) permit routing of a transmission signal of a multiplexed signal along an optical path from the first fiber stub to the second fiber stub, and (ii) prevent routing of a non-transmission signal of the multiplexed signal along the optical path from the first fiber stub to the second fiber stub. A distance between a first ferrule of the first fiber stub and a second ferrule of the second fiber stub is less than about 0.05 mm.

Disclosed is a compact device for wavelength-division multiplexing applications. In particular, disclosed is a device that includes a housing and a core at least partially positioned within the housing. The core includes a first single fiber stub, a second single fiber stub, and at least one functional layer positioned between a first fiber of the first single fiber stub and a second fiber of the second single fiber stub. The at least one functional layer is configured to: (i) permit routing of a transmission signal of a multiplexed signal along an optical path from the first fiber stub to the second fiber stub, and (ii) prevent routing of a non-transmission signal of the multiplexed signal along the optical path from the first fiber stub to the second fiber stub. A distance between a first ferrule of the first fiber stub and a second ferrule of the second fiber stub is less than about 0.05 mm.

An optical connection structure includes a first focus lens arranged between a first light incidence/emission end and an optical element, and a second focus lens arranged between a second light incidence/emission end and the optical element. The first focus lens and the second focus lens are arranged on an optical axis connecting the first light incidence/emission end and the second light incidence/emission end.

In some implementations, a wavelength division multiplexing (WDM) device includes a spacer; a first filter component; and a second filter component. The spacer is configured to propagate a light beam emitted from an input fiber of the WDM device within the spacer to the first filter component. The first filter component is configured to filter the light beam to create and direct a once-filtered light beam to the spacer. The spacer is configured to propagate the once-filtered light beam within the spacer to the second filter component. The second filter component is configured to filter the once-filtered light beam to create and direct a twice-filtered light beam to the spacer. The spacer is configured to propagate the twice-filtered light beam within the spacer to another component of the WDM device, such as another filter component, a mirror component, or an output fiber of the WDM device.

An optical wavelength-division multiplexing (WDM) device utilizing a mechanism of folded optical-path includes multiple collimators, optical filters, prism, and glass plate. The collimators are capable of collimating optical lights for facilitating free-space optical communication. The optical filters optically coupled with the collimators provide filtering functions to separate optical wavelengths in accordance with the configurations or characteristics of optical filters. The prism having an interface surface and two side surfaces is configured to direct or redirect optical beams based on the angle of incidence (AOI) of each optical beam received. The glass plate, in one embodiment, physically configured to be situated in parallel with the collimators is capable of providing free-space optical paths for facilitating separation of wavelengths.

The loopback apparatus disclosed herein is used with an optical fiber system having an optical fiber cable. The loopback apparatus includes an optical fiber having input and output ends and an output optical fiber having input and output ends. The loopback apparatus also includes an optical system that defines an optical path and that is configured to optically couple the output end of the input optical fiber with the input end of the output optical fiber over the optical path. The loopback apparatus also includes a thin-film filter disposed in the optical path and configured to provide a select amount of attenuation for light traveling over the optical path. The loopback apparatus can be plugged into and unplugged from the optical fiber cable. Loopback methods for measuring the performance of the optical fiber system using the loopback apparatus are also disclosed.

An optical signal isolation device comprising a common port, an isolated diagnostic port, an integrated circulator comprising an input circulator fiber, an output circulator fiber, and a fiber-to-fiber optical coupler configured to couple an isolated optical signal propagating along the input circulator fiber to the output circulator fiber for propagation along the output circulator fiber, a multi-fiber alignment body that secures at least portions of each of the multi-signal fiber, the isolated diagnostic signal fiber, the input circulator fiber, and the output circulator fiber, and a wavelength-selective optical assembly including an optical signal filter, fiber-to-filter focusing optics, and a communications signal reflector. The integrated circulator and the wavelength selective optical assembly are configured such that the communications component is retro-reflected back to the common port and the diagnostic component is passes out of the isolated diagnostic port.