In-line higher order mode filters based on long highly uniform fiber tapers

Broadband single-mode operation of standard optical fibers by using a sub-wavelength optical wire filter

“…Here we show that sub-wavelength optical wires (SOWs) [7,8] can be used as an efficient means to provide higher-order mode filtering in multimode waveguides, allowing effective single mode operation of conventional optical fibers over an extended wavelength range. Compared to the previous taper-based higher-order mode filtering architecture [9,10], the proposed SOW opens up the prospect of the manipulation of photons in fibers in the subwavelength domain. Due to this sub-wavelength guidance, SOWs can tightly confine the optical beam to a small area and can be used to ensure the propagating light experiences a strong interaction with the surrounding medium, especially near the surface at the nano-scale.…”

Endlessly single-mode operation of highly nonlinear photonic crystal fibers by controlled hole collapse

“…Higher-order modes have some special optical properties and applications; however, in many areas of the modern science and technology, stable single-mode operation in waveguide is a fundamental requirement, such as high performance fiber laser, sensors, photolithography, and optical coherent tomography systems [14,15]. For conventional communication fiber, there are many ways to filter higher-order modes at wavelength shorter than the cutoff wavelength of the optical fiber, such as sub-wavelength optical wires (SOWs) [16][17][18][19] and micro fiber coupler [20]. For largemode-area fiber, the coiling technique [21] is widely used.…”

Polarization-maintaining higher-order mode fiber module with anomalous dispersion at 1 μm

“…Only LP 01 is launched into the fiber using a highly uniform fiber taper in the fiber under test (FUT) [8]. The relative group delay is measured in a fiber piece of close to 1 km of length.…”

“…To launch only into the mode of interest, the beat length of LP 01 is measured in a fiber including a fiber taper for stripping the HOMs [8] and the beat length of LP 02 is measured on a GVD compensating PM HOM fiber The measurement is based on the sum of the measurement of the absolute difference in the group delay of LP 02 and LP 01 , which is shown in the inset, and an extrapolation of the relative group delay of LP 01 , plotted in Fig. 2(a).…”