Ion Implantation

By using silica/silicon wafers which have been implanted with Erbium with average concentrations of 2x1019 cm-3, we have been able to fabricate a planar microlaser.  The fabrication process is similar to that of  the silica ultra high microtoroids. By using the ultra high microtoroids, single mode lasing should be achieved and the final device is a planar structure.

To confirm that the laser annealing process used in the fabrication of the ultra high Q microtoroids does not effect the Er implantation, a photoluminescence spectra was taken (fig 1) before and after lasing. Additionally, before and after SEM images of the microtoroids are insets in this figure.

The microlaser is pumped at 1480nm, using an evanescently coupled tapered optical fiber. Cavity quality factors as high as 3.9x107 are achieved, corresponding to a modal loss of 0.007 dB/cm, and single-mode lasing is observed (fig 2, inset).  Additionally, a relationship between taper-resonator gap distance and lasing pump threshold was observed (fig 2).

More information can be found in the following papers:

T. J. Kippenberg, J. Kalkman, A. Polman, and K. J. Vahala
"Demonstration of an erbium-doped microdisk laser on a silicon chip"
Physical Review A, Volume 74, Art. No. 051802, November 2006.

J. Kalkman, A. Tchebotareva, A. Polman, T. J. Kippenberg, B. Min, and K. J. Vahala,
"Fabrication and characterization of erbium-doped toroidal microcavity lasers"
Journal of Applied Physics, Volume 99, 083103, 2006.

J. Kalkman, A. Polman, T. J. Kippenberg, K. J. Vahala, and M. L. Brongersma,
"Erbium-implanted silica microsphere laser"
Nuclear Instruments & Methods in Physics Research Section B, Volume 242, issue 1-2, January 2006.

A. Polman, B. Min, J. Kalkman, T. J. Kippenberg and K. J. Vahala
"Ultra-low-threshold erbium-implanted toroidal microlaser on silicon"
Applied Physics Letters, vol.84, No. 7, 1037-1039 February 2004.

B. K. Min, T. J. Kippenberg, L. Yang, K. J. Vahala, J. Kalkman, and A. Polman
“Erbium-implanted high-Q silica toroidal microcavity laser on a silicon chip”
Physical Review A, Volume 70, No. 3, 033803 September 2004.

 

fig 1 implantation

Figure 1: Photoluminescence spectra of Er-implanted microresonators before and after laser annealing (the spectrum for the disk is shifted vertically for clarity). The right inset shows photoluminescence decay traces measured at l=1535 nm for both a disk and a toroid. The left insets show scanning electron microscopy images of a microresonator disk and toroid. Scale bars are both 43 mm.

Er implantation figure 2

Figure 2: Launched pump power threshold for lasing as a function of relative coupling gap distance between fiber taper and Er-implanted microtoroid (diameter 45 mm). lpump=1480 nm, llasing=1578 nm. The drawn line is a guide for the eye. The inset shows a single-mode lasing spectrum measured under 1465 nm pumping.