Detailed investigation of self-imaging in largecore multimode optical fibers for application in fiber lasers and amplifiers

Zhu, Xiushan; Schülzgen, Axel; Li, H.; Li, L.; Han, Lin; Moloney, Jerome V.; Peyghambarian, N.

doi:10.1364/oe.16.016632

Cited by 74 publications

(37 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…4(a) and 4(b). It should be noted that achieving 100% perfect self-imaging (the normalized power is equal to 1) is impossible due to phase mismatches [36]. These features are consistent with the results in [34], [35], indicating that an explicit self-imaging of the input field is formed and the self-imaging period LZ for SNCS is equal to 58.64 mm.…”

Section: B the Self-imaging Periodssupporting

confidence: 83%

“…The degree of deviation (the difference between Dn and 'round (Dn)') may be attributed to two reasons: one is the errors in the calculations of the effective index by the graphical method; the other is the phase mismatches among the excited modes, which always exist although they are quite small [36]. The 100% perfect selfimaging is impossible due to phase mismatches [36], therefore 100% integer may be also impossible.…”

Section: Exploration Of the Discrete Characteristicsmentioning

confidence: 99%

See 1 more Smart Citation

Discrete Self-Imaging in Small-Core Optical Fiber Interferometers

Lian

Farrell

et al. 2019

J. Lightwave Technol.

View full text Add to dashboard Cite

Multiple cladding modes can exist in a small-core optical fiber unaccompanied by core modes, yet this fact has not been sufficiently explored in literature to date. In this article, we study the self-imaging of cladding modes in small core optical fiber interferometers. Our analytical and numerical simulations and experiments show that unlike the self-imaging of core modes, self-imaging of cladding modes only appears at a set of discrete positions along the interferometer axis with an equal spacing corresponding to some discrete values of fiber core radius. This is the first observation of the discrete self-imaging effect in multimode waveguides. More strikingly, the selfimaging period of cladding modes grows exponentially with fiber core radius, unlike the quadratic relationship in the case of core modes. The findings bring new insights to the mode propagation in an optical fiber with a core at micro/nanoscale, which may open new avenues for exploring multimode fiber technologies in both linear and nonlinear optics.

show abstract

Section: B the Self-imaging Periodssupporting

confidence: 83%

Section: Exploration Of the Discrete Characteristicsmentioning

confidence: 99%

Discrete Self-Imaging in Small-Core Optical Fiber Interferometers

Lian

Farrell

et al. 2019

J. Lightwave Technol.

View full text Add to dashboard Cite

show abstract

“…Multimode interference (MMI) has been successfully explored in various fiber optic applications in beam shapers, sensors, and filters [1][2][3][4][5][6][7][8]. In a multimode fiber, different guided modes have different phase velocities.…”

mentioning

confidence: 99%

“…The period of oscillations in Fig. 1(b) is given by Λ ¼ ffiffiffiffiffiffi ffi 2Δ p πR=ðδ × LÞ, where Λ is inversely proportional to L [6]. In Fig.…”

mentioning

confidence: 99%

Low-loss coupling between two single-mode optical fibers with different mode-field diameters using a graded-index multimode optical fiber

et al. 2011

View full text Add to dashboard Cite

We present a method for ultra-low-loss coupling between two single-mode optical fibers with different mode-field diameters using multimode interference in a graded-index multimode optical fiber. We perform a detailed analysis of the interference effects and show that the graded-index fiber can also be used as a beam expander or condenser. The results are important for devices in which optical fibers with different mode-field diameters are coupled in series, such as in ultra-short-pulse fiber ring lasers, or in optical fiber communication links.

show abstract

“…In general cases where nonlinear effects need to be considered, the phase shifts introduced by self‐phase modulation (SPM) and cross‐phase modulation (XPM) effects will change the self‐imaging beat length in GIMF varying the power coupling efficiency of the light from GIMF to SMF, which reveals the temporal intensity discrimination required for mode‐locking. The multimode light field distribution

E_{normalMM} false(r, \emptyset, z false)

along the GIMF can be expressed as: [ 28–30 ]

E_{normalMM} (r, \emptyset, z) = e^{- i β_{1} z} \sum_{n = 1}^{N} C_{n} e_{n} (r, \emptyset, z) e^{- i (β_{n} - β_{1}) z}

C_{n}

is the mode expansion coefficient, β 1 and

β_{n}

are the propagation constants of fundamental mode and the n th excited mode respectively. When the length of GIMF meets odd integer times of the half beat length,

L = false(m / 2 false) L_{self - imaging}^{'}

( m is an odd integer), the condition of the intensity discrimination can be satisfied, [ 24 ] Hence, all the modes satisfy

Δ β_{n} L = m π

Δ β_{n} = β_{i} - β_{j}

Δ n_{eff, n} = false(β_{i} - β_{j} false) λ_{0} / 2 π

, which can be written as:

Δ n_{eff, n} L = \frac{m}{2} λ_{0}

λ 0 is the central wavelength, L is the length of GIMF.…”

Section: Theoretical Considerationsmentioning

confidence: 99%

Gigahertz Harmonic Mode‐Locked Fiber Laser Based on Tunable SMS Ultrafast Optical Switch

et al. 2020

View full text Add to dashboard Cite

A novel passively gigahertz harmonic mode-locked all-fiber laser based on hybrid fiber structure (single-mode fiber-graded-index multimode fiber-single-mode fiber (SMS)) is proposed SMS, which coils on the paddles of polarization controller (PC), is demonstrated to modulate the temporal intensity for mode-locking. The nonlinear absorption properties of the optical switch are controllable by adjusting the paddles of PC; such an ultrafast optical switch enables the wavelength switchable harmonic mode-locking operation. Ultrafast pulses with 1.9 ps at 1558.41 nm and 0.95 ps at 1563.08 nm are generated. The maximum repetition rate of the laser up to 1.127 GHz harmonic of fundamental repetition mode-locking at 1563.08 nm, corresponding to 880 order, and the output power is 4.2 mW. Considering its superiority in terms of low cost, easy integration, and high reliability, the findings validate that SMS can be used in harmonic mode-locking.

show abstract

Detailed investigation of self-imaging in largecore multimode optical fibers for application in fiber lasers and amplifiers

Cited by 74 publications

References 14 publications

Discrete Self-Imaging in Small-Core Optical Fiber Interferometers

Discrete Self-Imaging in Small-Core Optical Fiber Interferometers

Low-loss coupling between two single-mode optical fibers with different mode-field diameters using a graded-index multimode optical fiber

Gigahertz Harmonic Mode‐Locked Fiber Laser Based on Tunable SMS Ultrafast Optical Switch

Contact Info

Product

Resources

About