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Mode scrambler

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


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Proceedings ArticleDOI
01 Jul 1997
TL;DR: In this paper, the authors developed a theory of rational mode-locked fiber laser and compared the results with experimental results obtained from a 1.5 (mu) fiber laser with a LiNbO3 electro-optic phase modulator.
Abstract: Optical pulse sources with repetition rate approaching terahertz are very important for many photonics applications including ultra-high speed optical communication and generation of sub-mm waves. Both active and passive mode locked fiber lasers are the appropriate choice for this purpose because of the availability of erbium doped fiber amplifier. In general, the mode locking occurs with a repetition rate of nf0, where n is an integer and f0 is the longitudinal mode frequency spacing. This is called harmonic mode locking. In the case of rational harmonic mode locking, the repetition rate is (np plus 1) f0 where p is also another integer. For the case of active mode locking, this is obtained when the modulation frequency to the amplitude or phase modulator used for mode locking is given by (n plus 1/p) f0. For the case of passive mode-locking, the rational harmonic mode-locking occurs when the saturable absorber in a ring laser is offset by a fraction p/L: from the center where L is the length of the cavity. We have developed a theory of the rational mode locked fiber laser. The results of the theory are compared with experimental results obtained from a 1.5 (mu) fiber laser actively mode-locked with a LiNbO3 electro-optic phase modulator.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

8 citations

Journal ArticleDOI
TL;DR: In this paper, the influence of large-signal modulation on mode oscillation in InGaAsP/InP lasers was investigated in terms of the temporal trajectories of the total output and the strongest modes as well as their Fourier spectra.
Abstract: This paper investigates influence of large-signal modulation on mode oscillation in InGaAsP/InP lasers. The mode competition dynamics under modulation are examined in terms of the temporal trajectories of the total output and the strongest modes as well as their Fourier spectra. The mode coupling induced by the strong spectral gain suppression is evaluated by both the correlation coefficients among the strongest modes and their signal distortion. We show that small and moderate modulations at the multimode hopping of the laser modulate the mode hopping along with modulation of each mode. The mode coupling is characterized by anti-correlation among the modes like as the non-modulated laser. Under modulation with the resonance frequency, the increase in the modulation depth changes mode coupling from anti-correlation to positive correlation and then to complete coupling that correspond to emission of periodic pulses. The mode coupling is characterized by mode competition distortion, which measures the amount of power carried by the mode signal at the frequency of multimode-hopping.

8 citations

Journal ArticleDOI
TL;DR: In this article, a selective excitation techique is used to measure the performance of multimode optical passive components by using a selective excitation technology and an accurate centering technique of monomode and multimode splices or connectors.
Abstract: Modal performances of multimode optical passive components are measured by use of a selective excitation techique. Pure LPm1 modes up to LP15 1 mode are generated in a Ti: sapphire laser cavity and launched in the input fiber of the component under test. Azimuthal dependency of the LP11 mode excitation coefficient is used in an accurate centering technique of monomode and multimode splices or connectors.

8 citations

Proceedings ArticleDOI
20 May 2013
TL;DR: In this article, the authors studied the mode field expansion in MOFs having triangular lattice, and low-loss splicing of MOFs to standard single-mode fibers (SMFs), based on the controlled all airhole collapse method, which leads to an optimum mode-field match at the joint interface of the MOF-SMF.
Abstract: The mode-field expander (MFE) is a microstructured optical fiber (MOF) based device that enlarges the modal field distribution and can couple light from large mode area (LMA) fibers into small core fibers or vice-versa and other optical waveguides. Using our earlier developed analytical field model, we studied the mode-field expansion in MOFs having triangular lattice, and low-loss splicing of MOFs to standard single-mode fibers (SMFs), based on the controlled all airhole collapse method, which leads to an optimum mode-field match at the joint interface of the MOF-SMF. Comparisons with available experimental and simulation results have also been included.

8 citations

Journal ArticleDOI
TL;DR: In this article, the authors proposed an optical mode switch based on the partial phase shift of injected light, and they focused on the bending radius of the S-bend waveguide issue that is connected to the multi mode waveguide in the Y-junction section that acts as mode combiner.
Abstract: We have proposed an optical mode switch, the principle of which is based on the partial phase shift of injected light; therefore, one important issue is to clarify the proper design criteria for the mode combiner section. We focused on the bending radius of the S-bend waveguide issue that is connected to the multi mode waveguide in the Y-junction section that acts as mode combiner. Long radius leads to undesired mode coupling before the Y-junction section, whereas a short radius causes radiation loss. Thus, we simulated this mode combiner by the beam-propagation method to obtain the proper radius. In addition, we used a trench pin structure to simplify the fabrication process into a single-step dry-etching process. As a result, we successfully fabricated an optical-mode switch with the bending radius R = 610 µm. It showed the successful electrical mode switching and the achieved mode crosstalk was approximately −10 dB for 1550 nm wavelength with the injection current of 60 mA (5.7 V).

8 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20234
202220
20213
20202
20196
20186