Fiber lasers and optoelectronic devices based on few layers of graphene - Lucia Akemi

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  • 1. Fiber lasers and optoelectronic devices based on few layers of graphene Workshop CPqD / Bristol University Program Lúcia A. M. Saito Mackgraphe - Centro de Pesquisas Avançadas em Grafeno, Nanomateriais e Nanotecnologia Mackenzie Presbyterian University 2014
  • 2. Outline Part I - Previous work: • Actively mode-locking Erbium fiber lasers with meters and kilometers long • In-field and in-laboratory 50 km ultralong Erbium-doped fiber lasers Part II - Future Interests: • Graphene Properties • Graphene-based optical modulators – Electroabsorption modulator based on monolayer graphene – Double-Layer Graphene Optical Modulator – MZ Graphene Optical Modulator • Final remarks 2
  • 3. Previous work: Actively mode-locking Erbium fiber lasers with meters and kilometers long
  • 4. Ultralong Erbium-doped Fiber Lasers  Length of 10 cavities: 16.4 m to 100.8 km  Total intracavity loss: 3.7 to 22.9 dB.  Erbium-doped fiber: • Absorption coefficient: -33.8 dB/m • Dispersion coefficient: -57.0 ps/nm.km 4
  • 5. 5 Pave = 1.8 mW Pulse Width as a function of Dispersion and Cavity Length
  • 6. 6 Analysis of Dispersion and Nonlinearity Length Setup Lcav LD (km) LNL (km) Lcav / LD Lcav / LNL Analysis 1 16.4 m 36.59 3.06 0.0005 0.0054 I – Neither dispersive nor nonlinear effects 2 51.6 m 12.54 2.41 0.0041 0.0214 3 218.0 m 12.74 2.61 0.0171 0.0835 4 1.4 km 11.63 2.56 0.1204 0.5469 II – Nonlinearity- dominant regime (Lcav ~ LNL)5 3.0 km 13.49 2.73 0.2224 1.0989 6 12.6 km 14.36 2.80 0.8774 4.5000 III – Dispersion (Lcav ~ LD) and nonlinearity- dominant regime (Lcav > LNL) 7 25.3 km 18.82 3.26 1.3443 7.7607 8 50.6 km 44.26 4.92 1.1432 10.2846 9 75.7 km 65.85 6.00 1.1496 12.6167 10 100.8 km 83.74 6.76 1.2037 14.9112
  • 7. 7 Possibility of soliton formation in all cavity setups. Analysis of Soliton Power and Soliton Period as a function of D and Lcav The parameter Z / Lcav is constant (~1.35) for ultralong cavities.
  • 8. Analysis of Output Spectrum The profiles of the spectrums confirm the dynamics of pulses in ultralong cavities. 8
  • 9. 9 In-field (Kyatera Network) 50 km Ultralong Erbium Fiber Lasers (in-lab and in-field)
  • 10. 10 Dispersion and nonlinear effects change the pulse duration at low modulation frequency. Pulse duration is shorter than expected by theory Output Pulse Width as a function of Modulation Frequency
  • 11. Future Interests: Optoelectronic devices based on few layers of graphene
  • 12. K. S. Novoselov et al., Nature Vol. 490, p.192 (2012). Graphene-based photonics applications: Possible application timeline, enabled by continued advances in graphene technologies, based on projections of products requiring advanced materials such as graphene. The figure gives an indication of when a functional device prototype could be expected based on device roadmaps and the development schedules of industry leaders. 12
  • 13. Graphene Properties • High-speed operation. Graphene-based electronics may have the potential to operate at THz, depending on the carrier density and graphene quality. • Strong light-graphene interaction. In comparison to compound semiconductors, a monolayer of graphene possesses a much stronger interband optical transition. • Broadband operation (300 to 2500 nm for SLG). The optical absorption of graphene is independent of wavelength. M. Liu et al., Nature, Vol. 474, p.64 (2011). Objective: to investigate optoelectronic properties and to develop the photonic devices based on few layers of graphene. 13
  • 14. • Monolayer graphene sheet • Device length: 40 μm • Broad optical bandwidth: 1350 to 1600 nm. M. Liu, X. Zhang, paper OTu1l.7, OFC/NFOEC 2012. Graphene-based optical modulators 16
  • 15. Electroabsorption modulator based on monolayer graphene Modulation depth: 0.1 dB/ μm DC measurement of the modulator: Electro-optics response of the device: Frequency limit: 1.2 GHz (measured 3 dB bandwidth) Drive voltages: 2.0 to 3.5 V 17
  • 16. Double-Layer Graphene Optical Modulator M. Liu, X. Yin, X. Zhang, Nano Letters Vol. 12, p.1482-1485 (2012) • Modulation depth: ~0.16 dB/μm • Modulator operates at 1 GHz • Device length: 40 μm • Double-layer 18
  • 17. Mach-Zehnder modulator • 8 graphene layers • Theoretical • Footprint: 4 x 30 μm2 • High modulation efficiency: 20V. μm • Large extinction ratio: 35 dB • Electro-refraction effect • Variation of effective mode index neff: 0.028 • Short arm length: 27.57 μm R. Hao et al., Applied Physics Letters Vol. 103, 061116 (2013) 19
  • 18. Ultra-compact optical modulator by graphene induced electro-refraction effect R. Hao, W. Du, H. Chen, X. Jin, L. Yang, E. Li, Applied Physics Letters Vol. 103, 061116 (2013) • Chemical potential is fixed μc1 = 1 eV. • Large extinction ratio: 35 dB 20
  • 19. Final Remarks Research Interests: • Development of optoelectronic devices such as modulators based on few layers of graphene. • Pulses generation in Erbium fiber lasers at ultrahigh repetition rates. Lúcia Saito lucia.saito@mackenzie.br Mackgraphe - Centro de Pesquisas Avançadas em Grafeno, Nanomateriais e Nanotecnologia 21