Browsing by Author "Lin, Fan-Yi"

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Nonlinear Dynamics of Semiconductor Lasers Under Repetitive Optical Pulse Injection
(2009-05-01)
Lin, Fan-Yi
;
Tu, Shiou-Yuan
;
Huang, Chien-Chih
;
Chang, Shu-Min
;
應用數學系
In this paper, nonlinear dynamics of semiconductor lasers under repetitive optical pulse injection are studied numerically. Different dynamical states, including pulsation and oscillation states, are found by varying the intensity and the repetition rate of the injection pulses. The laser is found to enter the chaotic pulsation (CP) states and chaotic oscillation (CO) states through individual period-doubling routes. Mapping and corresponding Lyapunov exponents of these dynamical states are plotted and examined in the parameter space. Moreover, the bandwidths of the chaos states found are investigated, where the bandwidths of the CP states observed at the strong injection regime are two to four times broader than the bandwidths of the CO states found at the weak injection regime. In this paper, frequency-locked states with different winding numbers, the ratio of the oscillation frequency, and the repetition frequency of the injection pulses are also studied. Both the cases for repetition frequency above and below the relaxation oscillation frequency are examined. The winding numbers of the frequency-locked states reveal a Devil's staircase structure, where a Farey tree showing the relations between the neighboring states is constructed.
Reconfigurable liquid-core/liquid-cladding optical waveguides with dielectrophoresis-driven virtual microchannels on an electromicrofluidic platform
(2016)
Fan, Shih-Kang
;
Lee, Hsuan-Ping
;
Chien, Chia-Chi
;
Lu, Yi-Wen
;
Chiu, Yi
An electrically reconfigurable liquid-core/liquid-cladding (L-2) optical waveguide with core liquid gamma-butyrolactone (GBL, n(core) = 1.4341, epsilon(core) = 39) and silicone oil (n(cladding) = 1.401, epsilon(cladding) = 2.5) as cladding liquid is accomplished using dielectrophoresis (DEP) that attracts and deforms the core liquid with the greater permittivity to occupy the region of strong electric field provided by Teflon-coated ITO electrodes between parallel glass plates. Instead of continuously flowing core and cladding liquids along a physical microchannel, the DEP-formed L-2 optical waveguide guides light in a stationary virtual microchannel that requires liquids of limited volume without constant supply and creates stable liquid/liquid interfaces for efficient light guidance in a simply fabricated microfluidic device. We designed and examined (1) stationary and (2) moving L-2 optical waveguides on the parallel-plate electromicrofluidic platform. In the stationary L-shaped waveguide, light was guided in a GBL virtual microchannel core for a total of 27.85 mm via a 90 degrees bend (radius 5 mm) before exiting from the light outlet of cross-sectional area 100 mu m x 100 mu m. For the stationary spiral waveguide, light was guided in a GBL core containing Rhodamine 6G (R6G, 1 mM) and through a series of 90 degrees bends with decreasing radii from 5 mm to 2.5 mm. With the stationary straight waveguide, the propagation loss was measured to be 2.09 dB cm(-1) in GBL with R6G (0.01 mM). The moving L-shaped waveguide was implemented on a versatile electromicrofluidic platform on which electrowetting and DEP were employed to generate a precise GBL droplet and form a waveguide core. On sequentially applying appropriate voltage to one of three parallel L-shaped driving electrodes, the GBL waveguide core was shifted; the guided light was switched at a speed of up to 0.929 mm s(-1) (switching period 70 ms, switching rate 14.3 Hz) when an adequate electric signal (173.1 V-RMS, 100 kHz) was applied.