Analysis of vertical radiation loss and far-field pattern for microcylinder lasers with an output waveguide

Abstract

Vertical radiation loss and far-field pattern are investigated for microcylinder lasers by 3D FDTD simulation and experimentally. The numerical results show that an output waveguide connected to the microcylinder resonator can result in additional vertical radiation loss for high Q coupled modes and affect the far field pattern. The vertical radiation loss can be controlled by adjusting the up cladding layer thickness. Furthermore, two lobes of vertical far-field patterns are observed for a 15-μm-radius microcylinder laser connected with an output waveguide, which confirms the vertical radiation loss.

Mode Investigation for Hybrid Microring Lasers With Sloped Sidewalls Coupled to a Silicon Waveguide

“…The mode field pattern deviations caused by the sloped sidewalls are studied, and the enhancements of waveguide coupling output efficiency and low threshold operation are expected with a tilting angle of about À6 . The hybrid microring lasers with the sloped sidewalls are fabricated using DVS-BCB bonding technique, and continuous-wave electrically injected lasing with the threshold current of 7.8 and 9 mA is obtained for a microring laser with a radius of 19 "m and a width of 2 "m at 12 and 22 C. For a hybrid microring laser with a radius of 29 "m and a ring width of 2.5 "m, continuous-wave electrical operation up to 50 C is achieved.…”

“…For the microring radius of 8 "m and the width of 2 "m, the CW lasing is achieved with the threshold current of 4.4 mA corresponding to the threshold current density of 5 kA/cm 2 . As the microring radius increases to 19 "m, the threshold current density decreases to 3.45 kA/cm 2 , due to the higher mode Q-factor. Obvious reductions of threshold current density and threshold current are observed for the microring width of 2.5 "m, mainly caused by relatively low radiation loss.…”

“…The width and height of the silicon waveguide are taken to be 500 nm and 350 nm. The refractive indices of the InP layer, the active region, the BCB layer and the silicon waveguide are 3.14, 3.4, 1.54 and 3.48, respectively [19]. The thicknesses of the insulating layer SiO 2 and the gold electrode layer are taken to be 300 nm and 200 nm, with the refractive indices of 1.45 and 0:18 þ i10:2, respectively.…”

Numerical Investigation on Feedback Insensitivity in Semiconductor Nanolasers

“…The enhancement of Purcell factor can be achieved in an SNL by enhancing the Q factor [33]. This is possible with changes in the nanolaser design by using highly reflective mirrors which can be attained by the use of metal coat [34][35][36][37][38][39][40], or by adjusting claddings on top of the active region to eliminate mode coupling [41,42].…”

Folded chaotic whispering-gallery modes in nonconvex, waveguide-coupled planar optical microresonators

“…In laser applications, they allow both efficient optical pumping and more complete collection of the emission. Although directional emission patterns from planar cavities can be made highly directional in the plane [8], losses by out-of-plane diffraction can be significant [9][10][11][12]. With attached waveguides, such losses are minimized.…”