Fabrication and characterization of erbium-doped toroidal microcavity lasers

Erbium-doped SiO2 toroidal microcavity lasers are fabricated on a Si substrate using a combination of optical lithography, etching, Er ion implantation, and CO2 laser reflow. Erbium is either preimplanted in the SiO2 base material or postimplanted into a fully fabricated microtoroid. Three-dimensional infrared confocal photoluminescence spectroscopy imaging is used to determine the spatial distribution of optically active Er ions in the two types of microtoroids, and distinct differences are found. Microprobe Rutherford backscattering spectrometry indicates that no macroscopic Er diffusion occurs during the laser reflow for preimplanted microtoroids. From the measured Er doping profiles and calculated optical mode distributions the overlap factor between the Er distribution and mode profile is calculated: Gamma=0.066 and Gamma=0.02 for postimplanted and preimplanted microtoroids, respectively. Single and multimode lasing around 1.5 µm is observed for both types of microtoroids, with the lowest lasing threshold (4.5 µW) observed for the preimplanted microtoroids, which possess the smallest mode volume. When excited in the proper geometry, a clear mode spectrum is observed superimposed on the Er spontaneous emission spectrum. This result indicates the coupling of Er ions to cavity modes.

[1]  Alexander Moroz,et al.  Local optical density of states in SiO 2 spherical microcavities: Theory and experiment , 2001 .

[2]  J. Raimond,et al.  Very low threshold whispering-gallery-mode microsphere laser. , 1996, Physical review. A, Atomic, molecular, and optical physics.

[3]  T. J. Kippenberg,et al.  Demonstration of ultra-high-Q small mode volume toroid microcavities on a chip , 2004 .

[4]  S. Spillane,et al.  Ultrahigh-Q toroidal microresonators for cavity quantum electrodynamics (10 pages) , 2004, quant-ph/0410218.

[5]  N. Olsson,et al.  Erbium-Doped Fiber Amplifiers: Fundamentals and Technology , 1999 .

[6]  M. Smit,et al.  A fast low-power optical memory based on coupled micro-ring lasers , 2004, Nature.

[7]  H. Haus.  Waves and fields in optoelectronics , 1983 .

[8]  J. Knight,et al.  Phase-matched excitation of whispering-gallery-mode resonances by a fiber taper. , 1997, Optics letters.

[9]  A. Polman,et al.  Erbium implanted thin film photonic materials , 1997 .

[10]  K. Vahala,et al.  Ideality in a fiber-taper-coupled microresonator system for application to cavity quantum electrodynamics. , 2003, Physical review letters.

[11]  K. Vahala,et al.  Ultralow-threshold erbium-implanted toroidal microlaser on silicon , 2004 .

[12]  Jean-Michel Gérard,et al.  Efficient coupling of Er-doped silicon-rich oxide to microdisk whispering gallery modes , 2005 .

[13]  K. Vahala,et al.  Ultralow-threshold microcavity Raman laser on a microelectronic chip. , 2004, Optics letters.

[14]  Marvin J. Weber,et al.  Luminescence Decay by Energy Migration and Transfer: Observation of Diffusion-Limited Relaxation , 1971 .

[15]  Kerry J. Vahala,et al.  Erbium-implanted high-Q silica toroidal microcavity laser on a silicon chip , 2004 .

[16]  A. Polman,et al.  Ion beam-induced anisotropic plastic deformation at 300 keV , 2003 .

[17]  J. Ziegler.  THE STOPPING AND RANGE OF IONS IN SOLIDS , 1988 .

[18]  Oskar Painter,et al.  Experimental demonstration of a high quality factor photonic crystal microcavity , 2003 .

[19]  H. Mabuchi,et al.  High-Q measurements of fused-silica microspheres in the near infrared. , 1998, Optics letters.

[20]  A. Polman,et al.  Coupling of Er ions to surface plasmons on Ag , 2005 .

[21]  W. Miniscalco.  Erbium-doped glasses for fiber amplifiers at 1500 nm , 1991 .

[22]  F. Priolo,et al.  Cooperative upconversion in erbium-implanted soda-lime silicate glass optical waveguides , 1995 .

[23]  Larry R. Dalton,et al.  Polymer micro-ring filters and modulators , 2002 .

[24]  K. Vahala,et al.  Kerr-nonlinearity optical parametric oscillation in an ultrahigh-Q toroid microcavity. , 2004, Physical review letters.

[25]  J. Zyskind,et al.  Determination of homogeneous linewidth by spectral gain hole-burning in an erbium-doped fiber amplifier with GeO/sub 2/:SiO/sub 2/ core , 1990, IEEE Photonics Technology Letters.

[26]  T. J. Kippenberg,et al.  Ultra-high-Q toroid microcavity on a chip , 2003, Nature.

[27]  J. Ziegler,et al.  stopping and range of ions in solids , 1985 .

[28]  Vladimir S. Ilchenko,et al.  Quality-factor and nonlinear properties of optical Whispering-Gallery modes , 1989 .