A method of making a multi-mode optical fiber that includes: depositing a porous germania-doped silica soot to form a germania-doped porous soot preform; depositing a porous silica layer over the porous soot preform; doping the porous soot preform and the porous silica layer with a fluorine dopant to form a co-doped soot preform having a core region and a fluorine-doped trench region; consolidating the co-doped soot preform to form a sintered glass, co-doped core preform having a refractive index alpha profile between 1.9 and 2.2 measured at 850 nm; depositing a cladding comprising silica over the sintered glass, co-doped preform to form a multi-mode optical fiber preform; drawing the optical fiber preform into a multi-mode optical fiber. Further, the step of doping the germania-doped soot preform and the porous silica layer is conducted according to a doping parameter (Φ) that is set between 20 and 300, and given by:

[00001]$\Phi =\frac{1\times {10}^{14}.Math.R_{\mathrm{prc}}^2.Math.\exp \left(-E/{\mathrm{RT}}_{\mathrm{dop}}\right).Math.T_{\mathrm{dop}}^{1/2}}{x^{3/4}}.$

A method of making a multi-mode optical fiber that includes: depositing a porous germania-doped silica soot to form a germania-doped porous soot preform; depositing a porous silica layer over the porous soot preform; doping the porous soot preform and the porous silica layer with a fluorine dopant to form a co-doped soot preform having a core region and a fluorine-doped trench region; consolidating the co-doped soot preform to form a sintered glass, co-doped core preform having a refractive index alpha profile between 1.9 and 2.2 measured at 850 nm; depositing a cladding comprising silica over the sintered glass, co-doped preform to form a multi-mode optical fiber preform; drawing the optical fiber preform into a multi-mode optical fiber. Further, the step of doping the germania-doped soot preform and the porous silica layer is conducted according to a doping parameter (Φ) that is set between 20 and 300, and given by:

[00001]$\Phi =\frac{1\times {10}^{14}.Math.R_{\mathrm{prc}}^2.Math.\exp \left(-E/{\mathrm{RT}}_{\mathrm{dop}}\right).Math.T_{\mathrm{dop}}^{1/2}}{x^{3/4}}.$

Integrated optical component combine the functions of a Variable Optical Attenuator (VOA), a tap coupler, and a photo-detector, reducing the size, cost, and complexity of these functions. In other embodiments, the integrated optical component combines the functions of an optical switch, a tap coupler, and a photo-detector. A rotatable mirror is used to adjust the coupling of light from an input port or ports to one or more output ports. A pin hole with a surrounding reflective surface is used at the core end face of one or more output fibers, such that a portion of the output optical signal is reflected to a photodiode chip. The photo-detector provides an indication of the optical power that is being coupled to the output fiber. With appropriate electronic control circuitry, the integrated optical component can be used to set the output optical power at a desired or required level.

A disclosed optical device includes a first waveguide disposed between a branching portion and a multiplexing portion on a semiconductor substrate, and a second waveguide disposed between the branching portion and the multiplexing portion, the second waveguide being longer than the first waveguide. In the optical device, an optical confinement effect of the first waveguide is greater than an optical confinement effect of the second waveguide, the first waveguide has a curvature with a first curvature radius (Rs), the second waveguide has a curvature with a second curvature radius (Rl), and the first curvature radius is smaller than the second curvature radius.

An optical testing circuit on a wafer includes an optical input configured to receive an optical test signal and photodetectors configured to generate corresponding electrical signals in response to optical processing of the optical test signal through the optical testing circuit. The electrical signals are simultaneously sensed by a probe circuit and then processed. In one process, test data from the electrical signals is simultaneously generated at each step of a sweep in wavelength of the optical test signal and output in response to a step change. In another process, the electrical signals are sequentially selected and the sweep in wavelength of the optical test signal is performed for each selected electrical signal to generate the test data.

Optical transmission systems and methods are disclosed that utilize a QSM optical fiber with a large effective area and that supports only two modes, namely the fundamental mode and one higher-order mode. The optical transmission system includes a transmitter and a receiver optically coupled by an optical fiber link that includes at least one section of the QSM optical fiber. Transmission over optical fiber link gives rise to MPI, which is mitigated using a digital signal processor. The QSM optical fiber is designed to have an amount of DMA that allows for the digital signal processor to have reduced complexity as reflected by a reduced number of filter taps as compared to if the DMA were zero.

Optical transmission systems and methods are disclosed that utilize a QSM optical fiber with a large effective area and that supports only two modes, namely the fundamental mode and one higher-order mode. The optical transmission system includes a transmitter and a receiver optically coupled by an optical fiber link that includes at least one section of the QSM optical fiber. Transmission over optical fiber link gives rise to MPI, which is mitigated using a digital signal processor. The QSM optical fiber is designed to have an amount of DMA that allows for the digital signal processor to have reduced complexity as reflected by a reduced number of filter taps as compared to if the DMA were zero.

A wavelength division multiplexing device with reduced signal loss and lower cost includes a casing, focusing lenses, and light splitters. The casing has walls defining slots. The focusing lenses are in an array. The light splitter includes prisms and filters. Each filter has opposite ends, ends being received in slot of the second sidewall and slot of the fourth sidewall. The prisms are positioned at the bottom plate and correspond to the focusing lenses. Each prism has an inner inclined surface facing the corresponding filter and signal light is selectively refracted and directed, to extract light of a particular wavelength and allow the through transmission of unextracted light towards subsequent light splitters.

There is described an optical fiber coupler generally having: a first optical fiber having a longitudinally extending multimode guiding region and a first taper portion longitudinally extending between first and second locations of the first optical fiber, the first taper portion having a dimension progressively decreasing along a first taper direction from the first location to the second location; a second optical fiber having a longitudinally extending multimode guiding region and a second taper portion longitudinally extending between third and fourth locations of the second optical fiber, the second taper portion having a dimension progressively decreasing along a second taper direction from the third location to the fourth location; and a coupling region where at least a portion of the first taper portion is optically coupled to a portion of the second taper portion, with the first and second taper directions being opposite to one another.

A system and method are presented for coupling OAM optical beams to optical fibers. The system may include, for instance, an OAM beam generator, for receiving one or more of a plurality of input signals, and generating a different OAM mode signal for each input signal. The OAM beam generator may further be operative to adjust a location and/or an exit angle of the one or more OAM mode signals before sending the one or more OAM mode signals to a beam combiner that combines the one or more OAM mode signals into a combined mode OAM transmission. The system may further include a controller in communication with at least one crosstalk estimate sensor and the at least one OAM beam generator, the controller operative to optimize the crosstalk estimate by receiving the crosstalk estimate for one of the OAM mode signals, and sending control instructions instructing the OAM beam generator to adjust a location and/or an exit angle of the one or more OAM mode signals to reduce the crosstalk estimate.