Browsing by Author "Tsai, Feng-Mao"

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High quality factor circular photonic crystal microcavity lasers
(2007)
Lu, Tsan-Wen
;
Fan, Jyun-Hao
;
Tsai, Feng-Mao
;
Lee, Po-Tsung
;
光電工程學系
The isotropic photonic bandgap (PBG) with only 6.7% width variation of circular photonic crystal (CPC) is investigated by finite-difference time-domain (FDTD) method. Whispering gallery mode (WGM) is sustained in CPC microcavity from FDTD simulation. The WGM single-mode lasing with low threshold (similar to 0.13 mW) and high quality (Q) factor (> 10000) is obtained from well-fabricated devices.
High quality factor microcavity lasers realized by circular photonic crystal with isotropic photonic band gap effect
(2007-04-09)
Lee, Po-Tsung
;
Lu, Tsan-Wen
;
Fan, Jyun-Hao
;
Tsai, Feng-Mao
;
光電工程學系
The photonic band gap (PBG) effect and its isotropy of sunflower-type circular photonic crystal (CPC) are obtained and investigated from the transmission spectra performed by finite-difference time-domain (FDTD) method. The PBG directional width variation is found to be only 6.7%. A well-confined whispering gallery mode (WGM) with azimuthal number of 6 is obtained by FDTD simulation from the CPC microcavity formed by seven missing air holes (C2). Ascribed to the deep and isotropic PBG confinement, the WGM lasing with very-low threshold (similar to 0.13 mW) and very-high-quality (Q) factor (> 10 000) is obtained from well-fabricated CPC C2 microcavity lasers. (c) 2007 American Institute of Physics.
Investigation of whispering gallery mode dependence on cavity geometry of quasiperiodic photonic crystal microcavity lasers
(2006-12-04)
Lee, Po-Tsung
;
Lu, Tsan-Wen
;
Tsai, Feng-Mao
;
Lu, Tien-Chang
;
光電工程學系
Dodecagonal (12-fold) quasiperiodic photonic crystal (DQPC) microcavity lasers sustaining whispering gallery mode (WGM) are fabricated. Lasing characteristics of DQPC D2 microcavity lasers are obtained and compared with triangular lattice D2 photonic crystal (PC) lasers, and ultralow threshold is obtained. The strong WGM mode dependence on 12 nearest airholes of DQPC D2 microcavity and its fabrication tolerance is investigated and discussed by randomly varying the lattice of two separate regions. This mode dependence also indicates that one can enhance a WGM in different PC microcavities by modifying the cavity boundary to be circular. (c) 2006 American Institute of Physics.
Lasing actions of octagonal quasi-periodic photonic crystal micro-cavities
(2006)
Lee, Po-Tsung
;
Lu, Tsan-Wen
;
Tsai, Feng-Mao
;
Lu, Tien-Chang
;
光電工程學系
Lasing actions are obtained from well-fabricated octagonal quasi-periodic photonic crystal (OQPC) micro-cavities. The defect modes in OQPC micro-cavities are investigated and compared with the calculation results. A large single-mode lasing range over 200 nm without mode hopping is observed.
Lasing actions of octagonal quasi-periodic photonic crystal microcavities
(2007-03-01)
Lee, Po-Tsung
;
Lu, Tsan-Wen
;
Tsai, Feng-Mao
;
Lu, Tien-Chang
;
光電工程學系
Lasing actions are obtained from well-fabricated octagonal quasi-periodic photonic crystal (OQPC) microcavities. The defect modes in OQPC microcavities are investigated and compared with the calculation results obtained using the finite-difference time-domain (FDTD) method. A large single-mode lasing wavelength range over 200 nm without mode hopping and a high side-mode suppression ratio (SMSR) of over 30dB are observed, which result from the mode dependence suppression mechanism on the cavity geometry.
Octagonal quasi-photonic crystal single-defect microcavity with whispering gallery mode and condensed device size
(2007-05-01)
Lee, Po-Tsung
;
Lu, Tsan-Wen
;
Tsai, Feng-Mao
;
光電工程學系
;
Department of Photonics
We propose a new single-defect microcavity which supports well-confined whispering gallery mode in octagonal quasi-photonic crystals (OQPC) by shifting the eight nearest air holes around the cavity. Lasing action is observed and compared with the calculated results obtained using the finite-difference time-domain method. We also investigate the threshold dependence on the number of lattice periods of this OQPC microcavity and compare it with triangular lattice photonic crystal (PC) microcavity with similar cavity size. The OQPC microcavity exhibits only a 36% increase of threshold when the number of lattice periods decreases from eight to four, which is more advantageous than the triangular lattice PC microcavity for the shrinkage of device size.