Low-loss all-fiber photonic lantern (PL) mode multiplexers (MUXs) capable of selectively exciting the first six fiber modes of a multimode fiber (${\mathrm{LP}}_{01}$, ${\mathrm{LP}}_{11\mathrm{a}}$, ${\mathrm{LP}}_{11\mathrm{b}}$, ${\mathrm{LP}}_{21\mathrm{a}}$, ${\mathrm{LP}}_{21\mathrm{b}}$, and ${\mathrm{LP}}_{02}$) 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.

We present a new technique allowing the fabrication of large modal count photonic lanterns for space-division multiplexing applications. We demonstrate mode-selective photonic lanterns supporting 10 and 15 spatial channels by using graded-index fibres and microstructured templates. These templates are a versatile approach to position the graded-index fibres in the required geometry for efficient mode sampling and conversion. Thus, providing an effective scalable method for large number of spatial modes in a repeatable manner. Further, we demonstrate the efficiency and functionality of our photonic lanterns for optical communications. Our results show low insertion and mode dependent losses, as well as enhanced mode selectivity when spliced to few mode transmission fibres. These photonic lantern mode multiplexers are an enabling technology for future ultra-high capacity optical transmission systems.

One half of a $2\times 2$ fused taper single-mode fiber coupler is used for the all-fiber spatial and spectral beam combining of two fiber lasers.

An experimental study was carried out to determinate the power spectral density (PSD) of mono-dispersed bubbly flows in a vertical channel using flying hot-film anemometry. To improve bubble detection, optical fibers were installed in close proximity to the anemometer sensing element; in this way, the collisions of bubbles with the probe can be detected and removed from the signal. Measurements were performed with gas fractions up to 6%. The PSD distributions were found to decay with a power of −3, in agreement with previous studies, but for a much wider range of Reynolds and Weber numbers. Our measurements indicate that the power decay does not depend strongly on the nature of hydrodynamic interactions among bubbles.

We experimentally demonstrate the operation of a pulsed source based on self-phase modulation followed by offset spectral filtering. This source has three operation regimes: a continuous-wave regime, a self-pulsating (SP) regime where the source self ignites and produces pulses, and a pulse-buffering (PB) regime where no new pulse is formed from spontaneous noise but only pulses already propagating, or potentially pulses injected in the cavity, can be sustained. In the SP and PB regimes, the pulsed source is multiwavelength and continuously tunable over the entire gain band of the amplifiers. The output pulsewidth is quasi-transform-limited with respect to the spectral-width of the filters used in the cavity. Overall, this device is extremely simple to implement and is a strong candidate as a pulsed source and for signal buffering.