Mode scrambler

About: Mode scrambler is a research topic. Over the lifetime, 896 publications have been published within this topic receiving 13595 citations.

Fiber Mode Scrambler for the Subaru Infrared Doppler Instrument (IRD)

Abstract: We report the results of fiber mode scrambler experiments for the Infra-Red Doppler instrument (IRD) on the Subaru 8.2-m telescope. IRD is a fiber-fed, high precision radial velocity (RV) instrument to search for exoplanets around nearby M dwarfs at near-infrared wavelengths. It is a high-resolution spectrograph with an Echelle grating. The expected RV measurement precision is 1 m s-1 with a state of the art laser frequency comb for the wavelength calibration. In IRD observations, one of the most significant instrumental noise is a change of intensity distribution of multi-mode fiber exit, which degrades RV measurement precision. To stabilize the intensity distribution of fiber exit an introduction of fiber mode scrambler is mandatory. Several kinds of mode scramblers have been suggested in previous research, though it is necessary to determine the most appropriate mode scrambler system for IRD. Thus, we conducted systematic measurements of performance for a variety of mode scramblers, both static and dynamic. We tested various length multi-mode fibers, an octagonal fiber, a double fiber scrambler, and two kinds of dynamic scramblers, and their combinations. We report the performances of these mode scramblers and propose candidate mode scrambler systems for IRD.

LP 11 –LP 01 Mode Conversion Based on an Angled-Facet Two-Mode Fiber

Abstract: We propose and experimentally demonstrate LP11–LP01 mode conversion based on an angled-facet two-mode fiber (AFTMF) It is a simple device based on a standard two-mode fiber with an output facet angle of 43° At a specific orientation, an incident LP11 beam on the angled-facet can be transformed into a transmitted beam with single-lobe mode profile The single-lobe beam coupled into a target few-mode fiber (FMF) has successfully excited LP01 mode in the target FMF The feasibility of the AFTMF to operate as a mode converter is demonstrated The proposed device is a simple and low-cost mode conversion tool for the space division multiplexing system

Characteristics of photonic crystal fibers designed with an annular core using a single material

Abstract: We propose a kind of photonic crystal fiber (PCF) designed with an annular core and fabricated using a single material. Characteristics of such fibers, including the mode field distributions of both the core and cladding modes, the effective mode area of the fundamental core mode, and the dispersion profile, are investigated using the finite element method. The coupling between the fundamental mode and an excited core mode or cladding mode is discussed in order to apply the proposed design in mode-coupling devices. Results show that such a PCF may be suitable for both optical communications and optical sensing technologies.

Simulation and analysis of mode staff excitation during “O”-band optical signal launching to graded multimode fiber with large central defect of refractive index profile via standard singlemode fiber

Abstract: We present modified technique for differential mode delay map measurement. Here according to well-known methods a fast laser pulse is also launched into a tested multimode fiber (MMF) via single mode fiber (SMF), which scans core of MMF under precision offset positions. However unlike known technique formalized in ratified standards, proposed modification differs by addition scanning of the output end of tested MMF by short tail of SMF. Therefore for each radial offset position at the input/output MMF ends, the shape of pulse response of launched optical signal is recorded, that provides to get more informative differential mode delay map. This work presents some results of experimental approbation of proposed modified technique for differential mode delay map measurement.

Dispersion compensation device

Abstract: The present invention is a dispersion compensation device capable of varying dispersion compensation amount with a simple configuration. The device includes a first mode light conversion section capable of converting input light into light of higher mode, a dispersion compensation section capable of performing dispersion compensation on the higher mode light outputted from the first mode light conversion section corresponding to the status of mode of the higher mode light, a second mode light conversion section capable of converting the light of higher mode dispersion-compensated in the dispersion compensation section into light of original mode, and a mode control section capable of variably controlling the status of mode of the higher mode light converted in the first mode light conversion section, and controlling to convert the higher mode light from the dispersion compensation section to the light of original mode in the second mode light conversion section.