A device. At least some example embodiments are a device including a filter element configured to receive optical energy from a first optical fiber. The filter element is reflective in a preselected band of optical wavelengths. A first lens is configured to receive optical energy transmitted through the filter element. A shell is disposed about the optical filter and the first lens; surfaces of the first lens, the filter element and the shell form a first boundary portion of an internal volume of an interior of the shell. A fluid is sealably disposed within the internal volume.

The technology of this application relates to an optical component constituting a fiber amplifier, a fiber amplifier, and a manufacturing method. The optical component is connected to a gain fiber by using a first fiber, or the optical component is directly connected to the gain fiber. The optical component is connected to one or more second optical components in the fiber amplifier by using a second fiber, and/or the optical component inputs an optical signal or outputs an optical signal amplified by the gain fiber by using the second fiber. Softening temperatures and/or refractive indexes of the first fiber and the second fiber are different, or softening temperatures and/or refractive indexes of the second fiber and the gain fiber are different.

An interference filter module comprises two optical fiber collimators arranged on an optical axis so as to be opposed to each other, interference filters, and a casing including a main body portion and filter holding portions to be mounted into the main body portion, which are configured to hold the interference filters. Two interference filters including a kth filter when counted from a front end and a k-th filter when counted from a rear end are determined as a k-th set. The two interference filters of the k-th set are accommodated in two filter holding portions, each of which is a k-th holding portion when counted from the front end and the rear end, respectively. The two filter holding portions have rotation axes in directions orthogonal to a fore-and-aft direction and are rotatably held by the casing. The rotation axes of the filter holding portions are orthogonal to each other.

In part, the disclosure relates to an apparatus that may include a first lens; wherein the first lens is enabled to be optically connected to an optical fiber; an isolator core optically coupled to the first lens; a second lens optically coupled to the isolator core; wherein the second lens is enabled to be optically connected to another optical fiber; wherein the isolator core is enabled to allow optical power from the first lens to propagate through the isolator core; wherein the isolator core is enabled to block optical power from the second lens from propagating through the isolator core; a first optical filter optically coupled to the first lens; and a second optical filter optically coupled to the second lens; wherein the second optical filter is enabled to reflect a first frequency; wherein the isolator core is enabled to absorb a remaining portion of the first frequency.

An integrated connector-wavelength division multiplexing (WDM) device includes a housing defining a housing interior and a connector interface having at least one ferrule, a device input optical fiber extending from the housing to carry an input optical beam, a device output optical fiber extending from the housing to carry an output optical beam, and a plurality of channel filters positioned in the housing interior. A first channel filter is connected to the input optical fiber and a second channel filter is connected to the output optical fiber, wherein each of the plurality of channel filters is configured to separate at least one optical signal from a plurality of optical signals of the input optical beam and provide the at least one optical signal to the at least one ferrule. A fiber optic module or submodule having one or more integrated connector-WDM devices is also disclosed.

An optical signal routing device may include a first lens, second lens and a wavelength division multiplexer (“WDM”) filter positioned between the first and second lenses. The WDM filter may reflect a signal of a first wavelength with a first attenuation and pass the first wavelength signal attenuated by at most a second attenuation to the second lens, the first attenuation exceeding the second attenuation by a first predetermined amount. The WDM filter may reflect a signal of a second wavelength different than the first wavelength with at most a third attenuation, the first attenuation exceeding the third attenuation by at least a second predetermined amount. The device may further include a reflector positioned to reflect the first wavelength signal reflected by the WDM filter toward the WDM filter with at least a fourth attenuation, the fourth attenuation exceeding the second attenuation by at least a third predetermined amount.

In an optical coupler in which optical fibers with GRIN lenses, each having an optical fiber and a GRIN lens joined coaxially, are disposed to face each other coaxially, with a preset inter-lens distance WD being provided, and to couple transmission light of one of the optical fibers with GRIN lenses to the other one of the optical fibers with GRIN lens, an intermediate position of the inter-lens distance WD is set to match a beam waist position of light with a shortest wavelength λ.sub.m out of the transmission light, and a lens length z along an optical axis direction of the GRIN lens is set in accordance with a bottom of a coupling loss due to a distance-shift D of a beam waist position of light with a wavelength λ.sub.i different from the λ.sub.m out of the transmission light.

An optical connection apparatus comprising a prism that extracts N×M beams of outgoing light from an optical circuit, a two-dimensional GRIN lens array of N×M GRIN lenses, a spacer, having a thickness according to the optical path length in the prism, that transmits N×M outgoing beams from the two-dimensional GRIN lens array, and a two-dimensional fiber array that causes the N×M beams to be incident on optical fibers, the ends of optical fibers being disposed at the focal point of each of the beams transmitted through the spacer.

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.

An optical amplification apparatus includes an optical amplification medium, having a gain in a wavelength band of signal light, configured to receive the signal light; excitation light introduction means for introducing, into the optical amplification medium, excitation light to excite the optical amplification medium; and residual excitation light introduction means for introducing, into the optical amplification medium, residual excitation light output from the optical amplification medium, the residual excitation light having a wavelength component of the excitation light, wherein the residual excitation light introduction means includes, on a side of one end of the optical amplification medium, residual excitation light multiplexing means for multiplexing the signal light and the residual excitation light, and on a side of another end of the optical amplification medium, space propagation type wavelength demultiplexing means for wavelength-demultiplexing the signal light and the residual excitation light by means of a spatial optical system.