Real-world SDM deployment requires the development of a supporting ecosystem. Recent technological advancements allow for volume production of key components of this ecosystem, MCF fanouts, which meet demanding performance requirements.

We demonstrate a broadband, low-loss pair of fanouts fusion spliced to a 200-meter-long, 4-core, datacom MCF covering both the O- and C-bands with loss smaller than 0.6 and 0.4 dB, respectively. Near field mode profiling allows for fine adjustment of the mode field.

We have designed, developed, and deployed the world's first ultra-dense space division-multiplexing multicore fiber link in a conduit of a metro network. In a 10-mm-diameter fiber optic-cable, 288 4-core multicore fibers are arranged in 24 200-µm spiderweb collapsible ribbons. The multicore fibers are fusion-spliced to 576 fanout devices which provide conventional single-core interfaces at patch panels at both ends of the link.

SDM using multicore fibers has the potential to increase the bandwidth density of optical links as well as to improve performance of sensing systems including 3D shape sensing and fiber optic gyroscopes. These applications are advanced by the low insertion and return loss, wide bandwidth, passive add-drop multiplexer demonstrated here.

MCFs have been developed for submarine deployment. Reliability and insertion loss are gating factors for this demanding application. Here we demonstrate a 0.15-dB-loss fanout, which is fusion spliced to a pure-silica two-core submarine-grade MCF.

Sixty-one lasing fiber channels are passively combined in a monolithic optical resonator array to produce an output power above 200 W at two-micrometer wavelength with the central intensity enhanced by a factor of 8 compared to incoherent beam combination. The 61-channel lasing mode corresponds to a transitional state with 75-degree phase shift between neighboring cores and has a far-field peak intensity 4.6 times below theoretical prediction for a fully coherent array. A 7-channel mode corresponds to the anti-phase supermode of the Talbot cavity, which has no central lobe in the far field. The monolithic laser cavity is formed by a fiber array, which is drawn and fusion-spliced to an endcap serving as a Talbot cavity mirror without air gaps. The central intensity enhancement, which is achieved without spectral or polarization selectivity, improves as the number of channels increases. This is an important step towards a passively combined multichannel all-solid-state laser system.

SDM using uncoupled or coupled core multicore fibers promises to increase the bandwidth density in optical links. In addition, these fibers form a platform for various sensing systems, including 3D shape sensing. Both applications will be advanced by the low return loss fanout-multicore fiber assembly demonstrated here.

We have developed a multichannel output coupler enabling coherent beam combining in the two-micron spectral range. We demonstrate experimentally the combining of multiple beams utilizing a set of thulium-doped, double-clad, singlemode optical fibers. The fibers are pumped by fiber-pigtailed laser diodes at 793 nm via (4+1)x1 pump-signal combiners. The combiners are fabricated using vanishing-core technology, which allows for preservation of the mode field through the tapering process. The output of individual lasing channels is generated over a 20 nm spectral band at around 1970 nm without any spectrally selective elements. The slope efficiency of individual lasers is approximately 50% with respect to the pump power. All lasing channels are fused into a monolithic silica structure with channel spacing of 32 microns on a triangular lattice. The fused assembly is fabricated in a glass microforming tapering process with a draw ratio of 3.9. In the process, the mode field at 1970 nm expands slightly to about 15 microns at the end of the taper, while the outer diameter is reduced from 2.3 mm to approximately 590 microns. The tapered end is straight polished and fusion spliced to a 600- micron diameter silica glass rod. The rod is cleaved and optically polished at zero degrees. The length of the rod is one half of the Talbot distance for optimal coherent beam combining. In the experiment, an antiphase supermode is observed when only the seven inner channels are pumped, and an in-phase supermode is excited when the number of channels is nineteen or larger.

A 16-channel spatial-division multiplexed transceiver is demonstrated using a multicore fiber coupled to a dense array of co-integrated 56Gb/s GeSi electro-absorption modulators and photodetectors, realizing 896Gb/s aggregate bi-directional bandwidth in 1.47mm 2 silicon footprint.

We demonstrate an all-glass, 61-channel, flexible, two-dimensional optical fiber array with 37 inner channels matched to an array of vertical grating couplers of a multi-channel (16 Tx and 16 Rx) transceiver prototype occupying a chip area of only 0.16 mm2.

We have developed an all-glass, fusion spliceable polarization maintaining (6+1) x 1 pump/signal combiner for fiber lasers and amplifiers. We utilize an enhanced tapered fiber bundle technology for multimode pump channels and a vanishing core fiber for the single mode polarization maintaining large mode area (PLMA) signal channel. The signal channel of the combiner is optimized to match a double-clad PLMA fiber with 20 micron core and 400 micron glass cladding with 0.065 numerical aperture (NA). The multimode pump channels have 200 micron core and 240 micron cladding with NA of 0.22 designed to deliver high power 980 nm pump light. The same double-clad PLMA fiber is used as both the signal input channel and the combined output for the device. Polarization axes of the input and output PLMA fibers are aligned during the fusion splices to achieve polarization crosstalk below -20 dB. Utilizing this approach, we have achieved coupling loss of similar to 0.4 dB for the signal channel as measured from the input PLMA to the output PLMA at a wavelength of 1060 nm and coupling loss below 0.01 dB for all pump channels as determined from the measured temperature rise of the combiner package temperature as the optical pump power at 974 nm is increased up to 45 W. Low signal and pump losses result in high efficiency lasing or amplification at over a kW of pump power for high power applications where a single mode, high polarization extinction ratio output is required.

Microformed, adiabatically tapered optical waveguides utilizing a "vanishing core" concept possess unique properties that make them useful for dense multichannel coupling, spatial division multiplexing for communications and sensing, polarization control, and amplification.

We demonstrate a hexagonal, monolithic optical fiber array matched to 37 vertical grating couplers with 40 μm pitch for a silicon photonics optical interface, with standard deviation of coupling across all channels of 0.7 dB.

Microformed optical waveguides, made by tapering and/or twisting fibers as they are passed through a miniature heat zone, possess unique properties that may be exploited for polarization control, harsh-environment sensing, dense multichannel coupling, spatial division multiplexing, amplification, and optical switching.

In response to the optical packaging needs of a rapidly growing silicon photonics market, Chiral Photonics, Inc. (CPI) has developed a new generation of ultra-dense-channel, bi-directional, all-optical, input/output (I/O) couplers that bridge the data transport gap between standard optical fibers and photonic integrated circuits. These couplers, called Pitch Reducing Optical Fiber Arrays (PROFAs), provide a means to simultaneously match both the mode field and channel spacing (i. e. pitch) between an optical fiber array and a photonic integrated circuit (PIC). Both primary methods for optically interfacing with PICs, via vertical grating couplers (VGCs) and edge couplers, can be addressed with PROFAs. PROFAs bring the signal-carrying cores, either multimode or singlemode, of many optical fibers into close proximity within an all-glass device that can provide low loss coupling to on-chip components, including waveguides, gratings, detectors and emitters. Two-dimensional (2D) PROFAs offer more than an order of magnitude enhancement in channel density compared to conventional one-dimensional (1D) fiber arrays. PROFAs can also be used with low vertical profile solutions that simplify optoelectronic packaging while reducing PIC I/O real estate usage requirements. PROFA technology is based on a scalable production process for microforming glass preform assemblies as they are pulled through a small oven. An innovative fiber design, called the "vanishing core," enables tailoring the mode field along the length of the PROFA to meet the coupling needs of disparate waveguide technologies, such as fiber and on-chip. Examples of single-and multi-channel couplers fabricated using this technology will be presented.

We have developed a (6+1)x1 combiner for fiber lasers and amplifiers based on a glass fusion technology. We have combined a conventional fiber fusion technology for pump channels with a new design for a single mode signal channel, which utilizes a vanishing core technology. The approach has been developed for single channel spot size converters and pitch reducing optical fiber arrays (PROFAs). Flexibility of this technology allows a custom design to match both a single or large mode area fiber at the input and a required active fiber at the output. The technology allows two parameters, mode field diameter (MFD) and taper diameter or channel spacing to be adjusted independently resulting in low loss coupling for signal channel at input and output. Utilizing this approach we have obtained better than 0.3 dB coupling for a signal channel at 1550 nm with a standard SMF28 fiber at the input and an active fiber at the output, while using six conventional 105/125 micron fibers as pump channels operating at 974 nm efficiently coupled to a double-clad fiber. Low signal loss results in high efficiency lasing or amplification suitable for high power applications. This unique technology allows excellent coupling for the signal channel as well as for the pump channels and is amenable to even more pump channels if desired.

The “vanishing core” concept in conjunction with a highly uniform 7-core fiber makes possible a monolithic, low-loss, low crosstalk, independently addressable, multicore fiber link in an all-glass, spliceable fanout for MC fiber.