All-fiber few-mode multicore photonic lantern mode multiplexer.

The emergence of space division multiplexing (SDM) for ultrahigh capacity networks has heralded pioneering Petabit-class optical transmission systems. In parallel to novel SDM fibers, a new class of components to enable scalable, low-loss schemes for unlocking fiber capacity is being developed. In this work, an all-fiber mode selective photonic lantern mode multiplexer designed for launching into few-mode multicore fibers is demonstrated. This device is capable of selectively exciting LP01, LP11a and LP11b modes in a seven-core configuration, resulting in 21 spatial channels, with less than 38 dB core-to-core crosstalk and insertion loss below 0.4 dB. The multicore photonic lantern multiplexer is scalable to larger number of cores and modes per core, and can be easily integrated with emerging ultra-high bandwidth few-mode multicore optical communication systems.

Few-mode erbium-doped fiber amplifier with photonic lantern for pump spatial mode control.

We demonstrate a few-mode erbium-doped fiber amplifier employing a mode-selective photonic lantern for controlling the modal content of the pump light. Amplification of six spatial modes in a 5 m long erbium-doped fiber to ∼6.2 dBm average power is obtained while maintaining high modal fidelity. Through mode-selective forward pumping of the two degenerate LP21 modes operating at 976 nm, differential modal gains of <1 dB between all modes and signal gains of ∼16 dB at 1550 nm are achieved. In addition, low differential modal gain for near-full C-band operation is demonstrated.

Six mode selective fiber optic spatial multiplexer.

Low-loss all-fiber photonic lantern (PL) mode multiplexers (MUXs) capable of selectively exciting the first six fiber modes of a multimode fiber (LP01, LP11a, LP11b, LP21a, LP21b, and LP02) are demonstrated. Fabrication of the spatial mode multiplexers was successfully achieved employing a combination of either six step or six graded index fibers of four different core sizes. Insertion losses of 0.2-0.3 dB and mode purities above 9 dB are achieved. Moreover, it is demonstrated that the use of graded index fibers in a PL eases the length requirements of the adiabatic tapered transition and could enable scaling to large numbers.

Synchronized signaling delivery for broadband 60 GHz in-building optical wireless network based on digital frequency division multiplexing and digital Nyquist shaping.

A simple and low-cost synchronized signaling delivery scheme has been proposed for a 60 GHz in-building optical wireless network with 12.7Gbps throughput based on digital frequency division multiplexing and digital Nyquist shaping.

Delivering 10 Gb/s optical data with picosecond timing uncertainty over 75 km distance.

We report a method to determine propagation delays of optical 10 Gb/s data traveling through a 75 km long amplified fiber link with an uncertainty of 4 ps. The one-way propagation delay is determined by two-way exchange and cross correlation of short (< 1 ms) bursts of 10 Gb/s data, with a single-shot time resolution better than 2.5 ps. We thus achieve a novel optical communications link suited for both long-haul high-capacity data transfer and time transfer with picosecond-range uncertainty. This opens up the perspective of synchronized optical telecommunication networks allowing picosecond-range time distribution and millimeter-range positioning.

Power-efficient impulse radio ultrawideband pulse generator based on the linear sum of modified doublet pulses.

We propose a new and power-efficient impulse radio ultawideband (IR-UWB) pulse design concept. The proposed concept is based on a linear sum of modified doublet pulses. The proposed concept is both simulated and experimentally demonstrated. The experimental demonstration employs a photonic scheme that generates the designed pulse using two main steps, mainly optical shaping and differential detection. The optical shaping is performed using a single electro-optic modulator biased in the nonlinear portion of its transfer function, and the differential detection is performed using a balanced photodetector. The generated IR-UWB pulse is fully Federal Communications Commission compliant, even in the highly power-restricted global positioning system band. The proposed optical scheme has potential to be integrated on a compact optical chip and thus suitable for reliable, low-cost, high-speed, short-range UWB wireless access, such as in-building networks.

Cost optimization of optical in-building networks.

Optical fiber-based in-building network solutions can outperform in the near future copper- and radio-based solutions both regarding performance and costs. POF solutions are maturing, and can already today be cheaper than Cat-5e solutions when ducts are shared with electricity power cabling. We compare the CapEx and OpEx of in-building networks for fiber and Cat-5E solutions. For residential homes, our analysis shows that total network costs during economic lifetime are lowest for a point-to-point duplex POF topology.

Record high-speed short-range transmission over 1 mm core diameter POF employing DMT modulation.

We report multigigabit/second transmission capacity in 1 mm core diameter graded index plastic optical fiber (POF) exploiting off-the-shelf low-cost components and discrete multitone (DMT) modulation. Transmission capacities of 10.1 Gbits/s x 15 m and 12.7 Gbits/s x 3 m are achieved for average bit-error rates less than 10(-3).