Juan Carlos Alvarado Zacarias

Mode-selective amplification in a large mode area Yb-doped fiber using a photonic lantern

We demonstrate selective spatial mode amplification in a few mode, double-clad Yb-doped large mode area (LMA) fiber, utilizing an all-fiber photonic lantern. Amplification to multi-watt output power is achieved while preserving high spatial mode selectivity. We observe gain values of over 12 dB for all modes: LP01, LP11a, and LP11b, when amplified individually. Additionally, we investigate the simultaneous amplification of LP01+LP11a and LP11a+LP11b, and the resultant mode competition. The proposed architecture allows for the reconfigurable excitation of spatial modes in the LMA fiber amplifiers, and represents a promising method that could enable dynamic spatial mode control in high power fiber lasers.

Low-differential modal gain multimode fiber amplifiers (Conference Presentation)

As the nonlinear capacity limit of single mode fiber (SMF) transmission systems is being approached, space-division multiplexing (SDM) in multicore fibers (MCFs) or few-mode fibers (FMFs) is currently under intense investigations to achieve ultrahigh spectral efficiency per fiber. Meanwhile, a key advantage of SDM over simply increasing the number of SMFs, is its inherent device integration and resource sharing capability. This can potentially provide significant benefits in terms of the cost per bit in future optical networks. In order to efficiently address capacity scaling in a single optical fiber, few-mode and multicore erbium-doped fiber amplifiers are being developed. Critical for the implementation of SDM amplifiers is to achieve almost the same amount of gain for all spatial channels. In this respect, we have recently demonstrated multimode fiber amplifiers, supporting >15 modes, with a maximum differential modal gain of 2 dB and negligible mode mixing.

Generation of orbital angular momentum beams using all-fiber photonic lanterns (Conference Presentation)

Orbital angular momentum (OAM) beams, have attracted great attention in recent years. An OAM beam with a phase singularity is characterized by a helical phase front which provides an additional degree of freedom for wide amount of classical and quantum optical applications. However, despite many attempts to generate and manipulate OAM beams, a robust, reliable and scalable technique to directly address generation, multiplexing and low-loss transmission of the distinct OAM beams is still in great demand. Here, we review the development of all-fiber, ring core photonics lantern mode multiplexer to generate high quality OAM beams up to the second order within a broad spectral range of >550 nm. Our device is a 5-mode mode selective photonic lantern (MSPL) with an annular refractive index profile which is fully compatible with well-established ring core and vortex transmission fibers. Through the excitation of pairs of degenerate linearly polarized (LP) modes of the MSPL, we demonstrate the generation of high quality OAM beams up to the second order. In addition, we demonstrate multiplexing of two OAM modes (OAM+1+ OAM-2) to verify complex beam pattern generation of our all fiber devices. Furthermore, by splicing the end-facet of the photonic lantern to a ring core fiber, we achieve low-loss coupling of OAM modes while maintaining high contrast spiral phase patterns. These results demonstrate the potential of photonic lanterns for generating complex optical beams.

3×10 Gb/s mode group-multiplexed transmission over a 20 km few-mode fiber using photonic lanterns

We experimentally demonstrate 3×10 Gb/s mode group-multiplexed transmission with direction detection in a step-index few-mode fiber over a record reach of 20 km, enabled by low crosstalk photonic lanterns as mode group (de)multiplexers.

Toward single-mode UV to near-IR guidance using hollow-core anti-resonant silica fiber

Hollow-core anti-resonant (HC-AR) fibers with a “negative-curvature” of the core-cladding boundary have been extensively studied over the past few years owing to their low loss and wide transmission bandwidths. The key unique feature of the HC-AR fiber is that the coupling between the core and cladding modes can be made anti-resonant (strongly inhibited) by suitably arranging the anti-resonant tubes in the cladding, which results in low loss and broad spectral bandwidths. HC-AR fibers have been fabricated aimed at visible, near-or mid-IR transmission [1-4]. Here we fabricate and characterize a silica HC-AR fiber having a single ring of 7 non-touching capillaries, designed to have effectively single-mode operation and low loss from UV to near-IR.