Transmission of independent signals through a multimode fiber using digital optical phase conjugation

Czarske, Jürgen; Haufe, Daniel; Koukourakis, Nektarios; Büttner, Lars

doi:10.1364/oe.24.015128

Cited by 43 publications

(22 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Here we propose and demonstrate a very thin Raman imaging probe based on a 60 μm diameter multimode sapphire optical fiber (air cladding) for both the excitation and collection of Raman signal, without any additional focusing optics. The wave front control was performed by digital phase conjugation method [21][22][23], which has potentially shorter response time than the transmission matrix method [24,25] since no measurement of the matrix elements [26] is needed. The sapphire air-clad fiber with a theoretical numerical aperture (NA) of 1 is expected to have a high collection efficiency.…”

Section: Introductionmentioning

confidence: 99%

Raman imaging through multimode sapphire fiber

Deng¹,

Loterie²,

Konstantinou³

et al. 2019

Opt. Express

View full text Add to dashboard Cite

We report on a sapphire fiber Raman imaging probe's use for challenging applications where access is severely restricted. Small-dimension Raman probes have been developed previously for various clinical applications because they show great capability for diagnosing disease states in bodily fluids, cells, and tissues. However, applications of these sub-millimeter diameter Raman probes were constrained by two factors: first, it is difficult to incorporate filters and focusing optics at such small scale; second, the weak Raman signal is often obscured by strong background noise from the fiber probe material, especially the most commonly used silica, which has a strong broad background noise in low wavenumbers (<500-1700 cm −1). Here, we demonstrate the thinnest-known imaging Raman probe with a 60 μm diameter Sapphire multimode fiber in which both excitation and signal collection pass through. This probe takes advantage of the low fluorescence and narrow Raman peaks of Sapphire, its inherent high temperature and corrosion resistance, and large numerical aperture (NA). Raman images of Polystyrene beads, carbon nanotubes, and CaSO 4 agglomerations are obtained with a spatial resolution of 1 μm and a field of view of 30 μm. Our imaging results show that single polystyrene bead (~15 µm diameter) can be differentiated from a mixture with CaSO 4 agglomerations, which has a close Raman shift.

show abstract

Section: Introductionmentioning

confidence: 99%

Raman imaging through multimode sapphire fiber

Deng¹,

Loterie²,

Konstantinou³

et al. 2019

Opt. Express

View full text Add to dashboard Cite

show abstract

“…2 This technique has also been used to control the mode coupling in multimode¯bers. 38,39 Since the speckle patterns as shown in Fig. 2 are generated from the interference and coupling among modes, WFScan thus pose extra active mode control to improve the performance of the specklegram-based sensor.…”

Section: Resultsmentioning

confidence: 99%

Active wavefront shaping for controlling and improving multimode fiber sensor

Zhong

et al. 2019

J. Innov. Opt. Health Sci.

View full text Add to dashboard Cite

Wavefront shaping (WFS) techniques have been used as a powerful tool to control light propagation in complex media, including multimode fibers. In this paper, we propose a new application of WFS for multimode fiber-based sensors. The use of a single multimode fiber alone, without any special fabrication, as a sensor based on the light intensity variations is not an easy task. The twist effect on multimode fiber is used as an example herein. Experimental results show that light intensity through the multimode fiber shows no direct relationship with the twist angle, but the correlation coefficient (CC) of speckle patterns does. Moreover, if WFS is applied to transform the spatially seemingly random light pattern at the exit of the multimode fiber into an optical focus. The focal pattern correlation and intensity both can serve to gauge the twist angle, with doubled measurement range and allowance of using a fast point detector to provide the feedback. With further development, WFS may find potentials to facilitate the development of multimode fiber-based sensors in a variety of scenarios.

show abstract

“…Nowadays, the MMF is a key device in several fields of research. They are used in biophotonical applications [19,20,21,22,23,24,25,26] to gain access to hard-to-reach areas due to their flexibility and high number of degrees of freedom in a minimum space. These properties are particularly helpful for image transmission using the MMF as an ultrathin endoscope.…”

Section: Introductionmentioning

confidence: 99%

Physical Layer Security in Multimode Fiber Optical Networks

Rothe

Koukourakis

Radner

et al. 2020

Sci Rep

Self Cite

View full text Add to dashboard Cite

Inverse precoding algorithms in multimode fiber based communication networks are used to exploit mode dependent losses on the physical layer. This provides an asymmetry between legitimate (Bob) and unlegitimate (Eve) receiver of messages resulting in a significant SNR advantage for Bob. In combination with dynamic mode channel changes, Eve has no chance to reconstruct a sent message even in a worst case scenario in which she is almighty. This is the first time, Physical Layer Security in a fiber optical network is investigated on the basis of measured transmission matrices. These results show that messages can be sent securely with conventional communication techniques. Translating the task of securing data from software to hardware represents the potential of a scientific paradigm shift. The introduced technique is a step towards the development of cyber physical systems.

show abstract

Transmission of independent signals through a multimode fiber using digital optical phase conjugation

Cited by 43 publications

References 39 publications

Raman imaging through multimode sapphire fiber

Raman imaging through multimode sapphire fiber

Active wavefront shaping for controlling and improving multimode fiber sensor

Physical Layer Security in Multimode Fiber Optical Networks

Contact Info

Product

Resources

About