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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 19, Iss. 9 — Apr. 25, 2011
  • pp: 8406–8412
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Population inversion and low cooperative upconversion in Er-doped silicon-rich silicon nitride waveguide

Jee Soo Chang, In Yong Kim, Gun Yong Sung, and Jung H. Shin  »View Author Affiliations


Optics Express, Vol. 19, Issue 9, pp. 8406-8412 (2011)
http://dx.doi.org/10.1364/OE.19.008406


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Abstract

Single-mode, strip-loaded silicon-rich silicon nitride (SRSN) waveguide with 11 at.% excess Si and 1.7×1020 cm−3 Er was fabricated and characterized. By using a 350 nm thick SRSN:Er core layer and a 850 nm wide SiO2 strip, a high core-mode overlap of 0.85 and low transmission loss of 2.9 dB/cm is achieved. Population inversion of 0.73-0.75, close to the theoretical maximum, is estimated to have been achieved via 1480 nm resonant pumping, indicating that nearly all doped Er in SRSN are optically active. Analysis of the pump power dependence of Er3+ luminescence intensity and lifetime indicate that the Er cooperative upconversion coefficient in SRSN:Er is as low as 2.1×10−18 cm3/sec.

© 2011 OSA

1. Introduction

There has been a long quest to develop a Si-based light source that is compatible with the complementary metal-oxide-semiconductor (CMOS) technology for a monolithic, low-cost electro-photonic convergence [1

1. See, for instance, “Silicon Photonics,Topics in Applied Physics Vol. 94, edited by L. Pavesi and D. J. Lockwood (Springer, 2004). [PubMed]

]. Among the many diverse approaches, there has been a renewed interest in using silicon nitride (SiN), in combination with Er-doping, for such a purpose. SiN is widely used in CMOS process, and has many attractive optical properties as well. It has a high and controllable refractive index (≥2.0), enabling compact size and tight mode confinement, even when cladded with standard SiO2 or polymers [2

2. D. S. Gardner and M. L. Brongersma, “Microring and microdisk optical resonators using silicon nanocrystals and erbium prepared using silicon technology,” Opt. Mater. 27(5), 804–811 (2005). [CrossRef]

]. SiN is also highly transparent in the technologically important 1.5 μm region, enabling fabrication of devices such as low-loss waveguides [3

3. N. Daldosso, M. Melchiorri, F. Riboli, M. Girardini, G. Pucker, M. Crivellari, P. Bellutti, A. Lui, and L. Pavesi, “Comparison among various Si3N4 waveguide geometries grown within a CMOS fabrication pilot line,” J. Lightwave Technol. 22(7), 1734–1740 (2004). [CrossRef]

,4

4. M. Melchiorri, N. Daldosso, F. Sbrana, L. Pavesi, G. Pucker, C. Kompocholis, P. Bellutti, and A. Lui, “Propagation loss of silicon nitride waveguides in the near-infrared range,” Appl. Phys. Lett. 86(12), 121111 (2005). [CrossRef]

] and high-Q resonators [5

5. A. Gondarenko, J. S. Levy, and M. Lipson, “High confinement micron-scale silicon nitride high Q ring resonator,” Opt. Express 17(14), 11366–11370 (2009). [CrossRef] [PubMed]

7

7. S. Zheng, H. Chen, and A. W. Poon, “Microring-resonator cross-connect filters in silicon nitride: rib waveguide dimensions dependence,” IEEE J. Sel. Top. Quantum Electron. 12(6), 1380–1387 (2006). [CrossRef]

]. Finally, when doped with Er, SiN:Er emits light at 1.54 μm due to the 4I13/24I15/2 Er3+ intra-4f transition [8

8. J. S. Chang, K. Suh, M.-S. Yang, and J. H. Shin, “Development and application of Er-doped silicon-rich silicon nitrides and Er silicates for on-chip light sources,” “Silicon Photonics II,” Topics in Applied Physics Vol. 119, 95–130 (2011).

11

11. S. Yerci, R. Li, S. O. Kucheyev, T. van Buuren, S. N. Basu, and L. Dal Negro, “Energy transfer and 1.54 µm emission in amorphous silicon nitride films,” Appl. Phys. Lett. 95(3), 031107 (2009). [CrossRef]

], enabling fabrication and integration of light-emitting devices such as microdisk resonators [12

12. J. S. Chang, S. C. Eom, G. Y. Sung, and J. H. Shin, “On-chip, planar integration of Er doped silicon-rich silicon nitride microdisk with SU-8 waveguide with sub-micron gap control,” Opt. Express 17(25), 22918–22924 (2009). [CrossRef]

], photonic crystals [13

13. Y. Gong, M. Makarova, S. Yerci, R. Li, M. J. Stevens, B. Baek, S. W. Nam, R. H. Hadfield, S. N. Dorenbos, V. Zwiller, J. Vuckovic, and L. Dal Negro, “Linewidth narrowing and Purcell enhancement in photonic crystal cavities on an Er-doped silicon nitride platform,” Opt. Express 18(3), 2601–2612 (2010). [CrossRef] [PubMed]

], and light-emitting diodes [14

14. G. Y. Sung, N.-M. Park, J.-H. Shin, K.-H. Kim, T.-Y. Kim, K. S. Cho, and C. Huh, “Physics and device structures of highly efficient silicon quantum dots based silicon nitride light-emitting diodes,” IEEE J. Sel. Top. Quantum Electron. 12(6), 1545–1555 (2006). [CrossRef]

,15

15. S. Yerci, R. Li, and L. Dal Negro, “Electroluminescence from Er-doped Si-rich silicon nitride light emitting diodes,” Appl. Phys. Lett. 97(8), 081109 (2010). [CrossRef]

] on a Si chip.

Still, many questions remain. For instance, unlike other Er-doped thin film materials such as Al2O3, silicate glass, and silicates [16

16. W. J. Miniscalco, “Er-doped glasses for fiber amplifiers at 1500 nm,” J. Lightwave Technol. 9(2), 234–250 (1991). [CrossRef]

19

19. J. D. B. Bradley, L. Agazzi, D. Geskus, F. Ay, K. Wörhoff, and M. Pollnau, “Gain bandwidth of 80 nm and 2 dB/cm peak gain in Al2O3:Er3+ optical amplifiers on silicon,” J. Opt. Soc. Am. B 27(2), 187–196 (2010). [CrossRef]

], important optical parameters such as Er3+ optical absorption/emission cross-sections and the cooperative upconversion coefficient (CUC) of Er in SiN have not yet been reported. The most serious question, however, is whether doped Er in SiN can be inverted at all. There have been several reports that defect removal, and possibly optical activation of Er in SiN, may be incomplete even after annealing in excess of 1100 °C [8

8. J. S. Chang, K. Suh, M.-S. Yang, and J. H. Shin, “Development and application of Er-doped silicon-rich silicon nitrides and Er silicates for on-chip light sources,” “Silicon Photonics II,” Topics in Applied Physics Vol. 119, 95–130 (2011).

,20

20. A. Polman, D. C. Jacobson, D. J. Eaglesham, R. C. Kistler, and J. M. Poate, “Optical doping of waveguide materials by MeV Er implantation,” J. Appl. Phys. 70(7), 3778–3784 (1991). [CrossRef]

,21

21. I. Y. Kim, J. H. Shin, and K. J. Kim, “Extending the nanocluster-Si/erbium sensitization distance in Er-doped silicon nitride: The role of Er-Er energy migration,” Appl. Phys. Lett. 95(22), 221101 (2009). [CrossRef]

]. Unfortunately, in oxide-based materials, such a high temperature anneals have been shown to lead to optical de-activation of Er, down to levels where population inversion is impossible, especially if excess Si is present to provide higher refractive index contrast and broad-band sensitization for Er [22

22. P. Pellegrino, B. Garrido, J. Arbiol, C. Garcia, Y. Lebour, and J. R. Morante, “Site of Er ions in silica layers codoped with Si nanoclusters and Er,” Appl. Phys. Lett. 88(12), 121915 (2006). [CrossRef]

24

24. S. Minissale, T. Gregorkiewicz, M. Forcales, and R. G. Elliman, “On optical activity of Er3+ ions in Si-rich SiO2 waveguides,” Appl. Phys. Lett. 89(17), 171908 (2006). [CrossRef]

].

As high refractive index and possibility of broadband sensitization are two important motivations for investigating Er-doped SiN, these issues need to be resolved if research into Er-doped SiN for an on-chip light source is to be meaningful. In this letter, we report on the result of fabricating and characterizing single-mode, strip-loaded silicon-rich silicon nitride (SRSN) waveguides doped with 1.7×1020 cm−3 Er and 11 at.% excess Si. Due to the presence of excess Si, some degree of sensitization is observed. However, in this paper, we will focus on the conventional, resonant pumping of Er in SRSN. We find the peak emission cross section of Er is 0.8± 0.02 ×10−20 cm2 at 1536 nm. Even with a compact mode radius of 2.7 μm × 0.48 μm, a waveguide propagation loss of 2.9 ± 0.4 dB/cm at 1536 nm, which is lower than the maximum Er optical gain of 5 dB/cm, is obtained. Under resonant optical pumping at 1480 nm, a population inversion level of 0.73~0.75 out of maximum possible 0.75 is obtained, demonstrating that even with excess Si, nearly all of the doped Er is active. In addition, the CUC is determined to be as low as ≤ 2.1×10−18 cm3/sec, indicating that Er-doped SRSN has a high potential for applications in silicon based optical light devices and amplification.

2. Sample fabrication

350 nm thick, Er doped SRSN film was deposited on a 10 μm thermal oxide wafer by the ion beam sputtering deposition (IBSD) method. High temperature annealing in flowing N2 environment at 1100 °C for 20 min followed by hydrogenation by annealing at 650 °C for 30 min in forming gas was used to activate doped Er and passivate defects. The composition of the nitride layer was analyzed by the Rutherford backscattering spectroscopy to be 49 at. % Si, 51 at.% N, and 0.2 at.% (1.7×1020 cm−3) Er (data not shown). Note that such a composition indicates an excess Si content of 11 at. % over stoichiometric Si3N4. Afterward, a 230 nm thick SiO2 layer was deposited on top of the nitride layer, and 850 nm wide SiO2 strips were fabricated by e-beam lithography and dry etching. Figure 1(a)
Fig. 1 (a) Refractive index of the Er doped SiN film measured by ellipsometry and fitted by the single-pole Sellmeier equation. Calculated absorption coefficient (a=4pk/l) using the extinction coefficient (k), obtained by ellipsometry. (b) Measured Er3+ emission spectrum and estimated absorption spectrum by the relation, σem(ν)=σabs(ν)e(ε-hν)/kT [25,26]. (c) SEM image of a strip-loaded SRSN:Er waveguide prior to polishing. Inset shows the calculated single TE mode profile with same parameters.
shows the refractive index and absorption coefficient of SRSN:Er measured by ellipsometry, respectively. The refractive index of SRSN, was estimated using Sellmeier equation to be 2.055 at 1550 nm, while the absorption coefficient (α) was found to be negligible. Using the same method, refractive index of deposited SiO2 at 1550 nm was estimated to be 1.452 (data not shown).

The room temperature photoluminescence (PL) spectrum of the SRSN:Er film is as shown in Fig. 1(b). Knowing the emission spectrum allows us to calculate the absorption spectrum by the McCumber relation [25

25. D. E. McCumber, “Theory of phonon-terminated optical masers,” Phys. Rev. 134(2A), A299–A306 (1964). [CrossRef]

,26

26. P. C. Becker, N. A. Olsson, and J. R. Simpson, Erbium-Doped Fiber Amplifiers: Fundamentals and Technology (Academic Press, 1997).

]. Figure 1(c) shows a scanning electron microscope (SEM) image of a fully processed waveguide. The top surface of the waveguide and nitride layer is smooth and clean, but some sidewall roughness of the waveguide is noticeable. Shown in the inset is the calculated TE-like mode profile based on the SEM image, indicating that the waveguide is a single-mode with core-mode overlap (Γ) of 0.85.

3. Results and analysis

Figure 2(a)
Fig. 2 (a) Measured transmission spectrum (black) of a 0.58 cm length waveguide, fitted by the absorption spectrum (red) in Fig. 1(b). Er absorption is 2.9 dB at 1536 nm. (b) A linear fitted, waveguide length dependent transmission loss without Er loss.
shows the background-corrected transmission spectrum of a 0.58 cm long waveguide, obtained using a tunable laser, with the input polarization controlled by a polarization controller to a transverse electric-field (TE) mode. Also shown in red is the expected Er3+ absorption spectrum from Fig. 1(b), normalized to fit the observed transmission spectrum. We obtain a very good fit, indicating a good accuracy of the correction procedure. We observe a maximum Er3+ absorption loss of 2.9 dB, or 5.0 dB/cm at 1536 nm. As the Er3+ absorption loss is given by aErabs×NEr×Γ where σabs = Er absorption cross section, NEr = Er concentration, and Γ = the mode overlap of Er, σabs in SRSN is estimated to be 0.8 ±0.02 × 10−20 cm2 which is slightly larger, but is still very close to, the values of 0.5-0.7×10−20 cm2 for Er3+ in oxide-based materials [16

16. W. J. Miniscalco, “Er-doped glasses for fiber amplifiers at 1500 nm,” J. Lightwave Technol. 9(2), 234–250 (1991). [CrossRef]

]. Given σabs, the waveguide coupling and propagation losses at 1536 nm were determined by cut-back method, as is shown in Fig. 2(b). Each data point represents the average of at least five identically prepared waveguides. Using linear fit, we obtain waveguide coupling and propagation losses of 1.9 ± 0.3 dB/facet and 2.9 ± 0.4 dB/cm, respectively.

Population inversion and optical gain was investigated by pumping the 0.58 cm long waveguide with a co-propagating 1480 nm laser diode with a maximum pump power of 40 mW/40 mW (measured in front of lensed fiber) [17

17. K. Suh, M. Lee, J. S. Chang, H. Lee, N. Park, G. Y. Sung, and J. H. Shin, “Cooperative upconversion and optical gain in ion-beam sputter-deposited Er(x)Y(2-x)SiO(5) waveguides,” Opt. Express 18(8), 7724–7731 (2010). [CrossRef] [PubMed]

]. The black, green and red lines in Fig. 3(a)
Fig. 3 (a) An absorption (black) and gain (red) spectrum with co-propagating 1480 nm laser diode (LD) pumping at 40 mW/40 mW maximum pump power. A signal enhancement of 4.46 dB is observed. The green spectrum was measured at a lower pump power, 5 mW. The colored lines are estimated transmission spectra for different inversion levels (0, 0.4, 0.5, 0.6, 0.65, 0.75). (b) The signal enhancement as a function of input pump power. Note that the pump power is measured from input fiber, and not calibrated by the waveguide-fiber coupling loss.
show the signal transmission spectra under pump powers of 0, 5 and 40 mW, respectively. Also shown for comparison is the transmission spectra expected for various levels of population inversion [26

26. P. C. Becker, N. A. Olsson, and J. R. Simpson, Erbium-Doped Fiber Amplifiers: Fundamentals and Technology (Academic Press, 1997).

]. Upon pumping, we clearly observe increased transmission over all wavelengths. In particular, the dip in the transmitted intensity near 1536 nm due to Er absorption first disappears, and then changes into an emission peak, indicating population inversion. Based on comparison with the calculated transmission spectra, we estimate the level of population inversion to be ~0.75. Figure 3(b) shows the pump-power dependent increase in transmitted signal intensity at 1536 nm in more detail. The signal enhancement saturates at 4.46 dB, corresponding to on/off gain of 7.7 dB/cm. This is much larger than the Er absorption loss of 5 dB/cm shown in Fig. 2(a), and indicates a successful achievement of an internal gain of 2.7 dB/cm, As the amplified spontaneous emission is measured to be less than −40 dBm (data not shown), this confirms that the observed on/off gain is due to population inversion and not due to mere bleaching of Er3+ atoms. Since absorption by Er is given by α = σEr(N1-N2)Γ [26

26. P. C. Becker, N. A. Olsson, and J. R. Simpson, Erbium-Doped Fiber Amplifiers: Fundamentals and Technology (Academic Press, 1997).

], using the value of 0.8×10−20 cm2 for σEr derived above, we calculate level of population inversion to be 0.73, in good agreement with Fig. 3(a).

It should be noted, however, that due to non-zero emission cross-section of Er3+ at pump wavelength of 1480nm as shown in Fig. 1(b), the maximum possible inversion level is limited to 1-σemabs (=0.75) since the pump light can also lead to stimulated emission of excited Er3+ [28

28. E. Snoeks, G. N. Hoven, A. Polman, B. Hendriksen, M. B. J. Diemeer, and F. Priolo, “Cooperative upconversion in erbium-implanted soda-lime silicate glass optical waveguides,” J. Opt. Soc. Am. B 12(8), 1468–1474 (1995). [CrossRef]

,28

28. E. Snoeks, G. N. Hoven, A. Polman, B. Hendriksen, M. B. J. Diemeer, and F. Priolo, “Cooperative upconversion in erbium-implanted soda-lime silicate glass optical waveguides,” J. Opt. Soc. Am. B 12(8), 1468–1474 (1995). [CrossRef]

]. The fact that we achieve an inversion level of 0.75 is therefore demonstrates that even with 11 at. % excess Si and annealing temperature of 1100 °C, nearly all of the doped Er is active in SRSN. Still, the internal gain of 2.7 dB/cm is lower than the waveguide propagation loss of 2.9 dB/cm, so no net optical gain is yet possible. However, SiN-based resonators with Q-factors of 3×106, corresponding to propagation loss of 0.12 dB/cm, have already been reported [5

5. A. Gondarenko, J. S. Levy, and M. Lipson, “High confinement micron-scale silicon nitride high Q ring resonator,” Opt. Express 17(14), 11366–11370 (2009). [CrossRef] [PubMed]

]. Thus, with better fabrication processes, net optical gain should be achievable.

In Er-based light sources, the main factor limiting optical gain in many cases is cooperative upconversion: one excited Er3+ ion decays non-radiatively by exciting another excited Er3+ ion to a higher excited state, resulting in a net loss of an excited Er3+ ion [17

17. K. Suh, M. Lee, J. S. Chang, H. Lee, N. Park, G. Y. Sung, and J. H. Shin, “Cooperative upconversion and optical gain in ion-beam sputter-deposited Er(x)Y(2-x)SiO(5) waveguides,” Opt. Express 18(8), 7724–7731 (2010). [CrossRef] [PubMed]

,27

27. M. P. Hehlen, N. J. Cockroft, T. R. Gosnell, A. J. Bruce, G. Nykolak, and J. Shmulovich, “Uniform upconversion in high-concentration Er3+-doped soda lime silicate and aluminosilicate glasses,” Opt. Lett. 22(11), 1468–1474 (1997). [CrossRef]

29

29. G. N. van den Hoven, E. Snoeks, A. Polman, C. van Dam, J. W. M. van Uffelen, and M. K. Smit, “Upconversion in Er-implanted Al2O3 waveguides,” J. Appl. Phys. 79(3), 1258–1266 (1996). [CrossRef]

]. A hallmark of cooperative upconversion process is the appearance of 980 nm PL due to second-excited state to ground state (4I11/24I15/2) transition even when pumped at 1480 nm. However, as Fig. 4(a)
Fig. 4 (a) Photoluminescence observed by 1480 nm pumping shows no emission peak near wavelength 980 nm. (inset) Er3+ lifetime at 1536 nm when pumped resonantly (Ar 488 nm) with various pump powers. (b) The 1536 nm PL intensity was measured twice by increasing/decreasing the pump power. CUC of 2.1×10−18 cm3/sec was derived by fitting Eq. (1) (green line). The 2-level model without CUC (σabsϕ/(σabsϕ+σemϕ+1/tEr)) was also calculated for comparison (blue line). The absorption/emission cross section used for calculation at 1480 nm, was 4.7×10−21 cm2/1.53×10−21 cm2 based on Fig. 1(b).
shows, no such 980 nm PL could be measured from the SRSN:Er waveguides under 1480 nm pump even at pump powers sufficient to induce maximum population inversion. Furthermore, as the inset shows, the decay traces of 1536 nm Er3+ luminescence remains single exponential with a luminescent lifetime of 2.44 msec even when pumped at 430 mW with the 488nm line (4F7/24I15/2) of an Ar laser, without the double-exponential shape with a rapid initial decay that indicates significant cooperative upconversion [17

17. K. Suh, M. Lee, J. S. Chang, H. Lee, N. Park, G. Y. Sung, and J. H. Shin, “Cooperative upconversion and optical gain in ion-beam sputter-deposited Er(x)Y(2-x)SiO(5) waveguides,” Opt. Express 18(8), 7724–7731 (2010). [CrossRef] [PubMed]

,28

28. E. Snoeks, G. N. Hoven, A. Polman, B. Hendriksen, M. B. J. Diemeer, and F. Priolo, “Cooperative upconversion in erbium-implanted soda-lime silicate glass optical waveguides,” J. Opt. Soc. Am. B 12(8), 1468–1474 (1995). [CrossRef]

,29

29. G. N. van den Hoven, E. Snoeks, A. Polman, C. van Dam, J. W. M. van Uffelen, and M. K. Smit, “Upconversion in Er-implanted Al2O3 waveguides,” J. Appl. Phys. 79(3), 1258–1266 (1996). [CrossRef]

]. Taken together, Fig. 4(a) indicates that the effect of cooperative upconversion is small. Therefore, we have analyzed the 1480 nm pump power dependence of 1536 nm Er3+ luminescence intensity using the following equation for a 2-level model system that has been widely used to approximate the cooperative upconversion process in the weak limit [17

17. K. Suh, M. Lee, J. S. Chang, H. Lee, N. Park, G. Y. Sung, and J. H. Shin, “Cooperative upconversion and optical gain in ion-beam sputter-deposited Er(x)Y(2-x)SiO(5) waveguides,” Opt. Express 18(8), 7724–7731 (2010). [CrossRef] [PubMed]

,26

26. P. C. Becker, N. A. Olsson, and J. R. Simpson, Erbium-Doped Fiber Amplifiers: Fundamentals and Technology (Academic Press, 1997).

,28

28. E. Snoeks, G. N. Hoven, A. Polman, B. Hendriksen, M. B. J. Diemeer, and F. Priolo, “Cooperative upconversion in erbium-implanted soda-lime silicate glass optical waveguides,” J. Opt. Soc. Am. B 12(8), 1468–1474 (1995). [CrossRef]

,29

29. G. N. van den Hoven, E. Snoeks, A. Polman, C. van Dam, J. W. M. van Uffelen, and M. K. Smit, “Upconversion in Er-implanted Al2O3 waveguides,” J. Appl. Phys. 79(3), 1258–1266 (1996). [CrossRef]

]
IErσabsϕ+σemϕ+1/τ2CN{[1+4CNσabsϕ(σabsϕ+σemϕ+1/τ)2]1/21}
(1)
where σabs, σem, ϕ, τ, C, N is the absorption (excitation) cross section, emission cross section at 1480 nm, pump photon flux, Er3+ decay lifetime (measured to be 2.44 msec), CUC, and concentration of Er, respectively.

The result is shown in Fig. 4(b). The best fit is obtained with a CUC of 2.1×10−18 cm3/sec. This value is among the lowest reported from an Er-doped waveguide with comparable Er concentration [27

27. M. P. Hehlen, N. J. Cockroft, T. R. Gosnell, A. J. Bruce, G. Nykolak, and J. Shmulovich, “Uniform upconversion in high-concentration Er3+-doped soda lime silicate and aluminosilicate glasses,” Opt. Lett. 22(11), 1468–1474 (1997). [CrossRef]

] – in fact, as the blue line shows, a reasonable fit can still be obtained even if we completely neglect the cooperative upconversion process. Such a low value of CUC is of great importance for developing Er-doped SRSN based light sources, as it indicates that population inversion can be achieved at lower pump powers, or equivalently, higher Er concentrations may be used for higher optical gain at the same given pump power.

4. Conclusion

In conclusion,we have demonstrated fabrication and characterization of a single-mode, strip loaded SRSN:Er waveguide with 11 at.% excess Si and Er concentration, 1.7×1020 cm−3. The SRSN:Er thin films provide peak emission cross section of 0.8±0.02 × 10−20 cm2 which is comparable to the values reported for Er3+ in oxide-based materials. Also, maximum achievable optical inversion of 0.75 is achieved via 1480 nm resonant pumping, with internal gain of 2.7 dB/cm. The cooperative upconversion coefficient (CUC) was 2.1×10−18 cm3/sec, which is lower than the reported values for comparable Er concentration. Based on these results, we find that nearly all Er in SRSN are optically active and that population inversion is achievable at low pump power. Thus, we expect that Er doped silicon-rich silicon nitride (SRSN) thin films can be used as compact silicon based optical devices and in amplification.

Acknowledgments

This work was supported in part by the Korean Ministry of Education, Science and Technology (MEST) grant No. 2009-0087691 (BRL), 20100029255 (GRL), and the Mega Convergence R&D program of MKE (10ZC1110: Basic Research of the Ubiquitous Lifecare Module Development). J. H. Shin acknowledges support by WCU (World Class University) program, grant No. (R31-2008-000-10071-0). J. S. Chang acknowledges support by the POSCO TJ Park Postdoctoral Fellowship.

References and links

1.

See, for instance, “Silicon Photonics,Topics in Applied Physics Vol. 94, edited by L. Pavesi and D. J. Lockwood (Springer, 2004). [PubMed]

2.

D. S. Gardner and M. L. Brongersma, “Microring and microdisk optical resonators using silicon nanocrystals and erbium prepared using silicon technology,” Opt. Mater. 27(5), 804–811 (2005). [CrossRef]

3.

N. Daldosso, M. Melchiorri, F. Riboli, M. Girardini, G. Pucker, M. Crivellari, P. Bellutti, A. Lui, and L. Pavesi, “Comparison among various Si3N4 waveguide geometries grown within a CMOS fabrication pilot line,” J. Lightwave Technol. 22(7), 1734–1740 (2004). [CrossRef]

4.

M. Melchiorri, N. Daldosso, F. Sbrana, L. Pavesi, G. Pucker, C. Kompocholis, P. Bellutti, and A. Lui, “Propagation loss of silicon nitride waveguides in the near-infrared range,” Appl. Phys. Lett. 86(12), 121111 (2005). [CrossRef]

5.

A. Gondarenko, J. S. Levy, and M. Lipson, “High confinement micron-scale silicon nitride high Q ring resonator,” Opt. Express 17(14), 11366–11370 (2009). [CrossRef] [PubMed]

6.

E. Shah Hosseini, S. Yegnanarayanan, A. H. Atabaki, M. Soltani, and A. Adibi, “Systematic design and fabrication of high-Q single-mode pulley-coupled planar silicon nitride microdisk resonators at visible wavelengths,” Opt. Express 18(3), 2127–2136 (2010). [CrossRef] [PubMed]

7.

S. Zheng, H. Chen, and A. W. Poon, “Microring-resonator cross-connect filters in silicon nitride: rib waveguide dimensions dependence,” IEEE J. Sel. Top. Quantum Electron. 12(6), 1380–1387 (2006). [CrossRef]

8.

J. S. Chang, K. Suh, M.-S. Yang, and J. H. Shin, “Development and application of Er-doped silicon-rich silicon nitrides and Er silicates for on-chip light sources,” “Silicon Photonics II,” Topics in Applied Physics Vol. 119, 95–130 (2011).

9.

L. Dal Negro, R. Li, J. Warga, and S. N. Basu, “Sensitized erbium emission from silicon-rich nitrides/silicon superlattice structures,” Appl. Phys. Lett. 92(18), 181105 (2008). [CrossRef]

10.

R. Li, S. Yerci, and L. Dal Negro, “Temperature dependence of the energy transfer from amorphous silicon nitride to Er ions,” Appl. Phys. Lett. 95(4), 041111 (2009). [CrossRef]

11.

S. Yerci, R. Li, S. O. Kucheyev, T. van Buuren, S. N. Basu, and L. Dal Negro, “Energy transfer and 1.54 µm emission in amorphous silicon nitride films,” Appl. Phys. Lett. 95(3), 031107 (2009). [CrossRef]

12.

J. S. Chang, S. C. Eom, G. Y. Sung, and J. H. Shin, “On-chip, planar integration of Er doped silicon-rich silicon nitride microdisk with SU-8 waveguide with sub-micron gap control,” Opt. Express 17(25), 22918–22924 (2009). [CrossRef]

13.

Y. Gong, M. Makarova, S. Yerci, R. Li, M. J. Stevens, B. Baek, S. W. Nam, R. H. Hadfield, S. N. Dorenbos, V. Zwiller, J. Vuckovic, and L. Dal Negro, “Linewidth narrowing and Purcell enhancement in photonic crystal cavities on an Er-doped silicon nitride platform,” Opt. Express 18(3), 2601–2612 (2010). [CrossRef] [PubMed]

14.

G. Y. Sung, N.-M. Park, J.-H. Shin, K.-H. Kim, T.-Y. Kim, K. S. Cho, and C. Huh, “Physics and device structures of highly efficient silicon quantum dots based silicon nitride light-emitting diodes,” IEEE J. Sel. Top. Quantum Electron. 12(6), 1545–1555 (2006). [CrossRef]

15.

S. Yerci, R. Li, and L. Dal Negro, “Electroluminescence from Er-doped Si-rich silicon nitride light emitting diodes,” Appl. Phys. Lett. 97(8), 081109 (2010). [CrossRef]

16.

W. J. Miniscalco, “Er-doped glasses for fiber amplifiers at 1500 nm,” J. Lightwave Technol. 9(2), 234–250 (1991). [CrossRef]

17.

K. Suh, M. Lee, J. S. Chang, H. Lee, N. Park, G. Y. Sung, and J. H. Shin, “Cooperative upconversion and optical gain in ion-beam sputter-deposited Er(x)Y(2-x)SiO(5) waveguides,” Opt. Express 18(8), 7724–7731 (2010). [CrossRef] [PubMed]

18.

G. N. van den Hoven, R. J. I. M. Koper, A. Polman, C. van Dam, J. W. M. van Uffelen, and M. K. Smit, “Net optical gain at 1.53 μm, in Er-doped Al2O3 waveguides on silicon,” Appl. Phys. Lett. 68(14), 1886–1888 (1996). [CrossRef]

19.

J. D. B. Bradley, L. Agazzi, D. Geskus, F. Ay, K. Wörhoff, and M. Pollnau, “Gain bandwidth of 80 nm and 2 dB/cm peak gain in Al2O3:Er3+ optical amplifiers on silicon,” J. Opt. Soc. Am. B 27(2), 187–196 (2010). [CrossRef]

20.

A. Polman, D. C. Jacobson, D. J. Eaglesham, R. C. Kistler, and J. M. Poate, “Optical doping of waveguide materials by MeV Er implantation,” J. Appl. Phys. 70(7), 3778–3784 (1991). [CrossRef]

21.

I. Y. Kim, J. H. Shin, and K. J. Kim, “Extending the nanocluster-Si/erbium sensitization distance in Er-doped silicon nitride: The role of Er-Er energy migration,” Appl. Phys. Lett. 95(22), 221101 (2009). [CrossRef]

22.

P. Pellegrino, B. Garrido, J. Arbiol, C. Garcia, Y. Lebour, and J. R. Morante, “Site of Er ions in silica layers codoped with Si nanoclusters and Er,” Appl. Phys. Lett. 88(12), 121915 (2006). [CrossRef]

23.

J. S. Chang, J.-H. Jhe, M.-S. Yang, J. H. Shin, K. J. Kim, and D. W. Moon, “Effects of silicon nanostructure evolution on Er3+ luminescence in silicon-rich silicon oxide/Er-doped silica multilayers,” Appl. Phys. Lett. 89(18), 181909 (2006). [CrossRef]

24.

S. Minissale, T. Gregorkiewicz, M. Forcales, and R. G. Elliman, “On optical activity of Er3+ ions in Si-rich SiO2 waveguides,” Appl. Phys. Lett. 89(17), 171908 (2006). [CrossRef]

25.

D. E. McCumber, “Theory of phonon-terminated optical masers,” Phys. Rev. 134(2A), A299–A306 (1964). [CrossRef]

26.

P. C. Becker, N. A. Olsson, and J. R. Simpson, Erbium-Doped Fiber Amplifiers: Fundamentals and Technology (Academic Press, 1997).

27.

M. P. Hehlen, N. J. Cockroft, T. R. Gosnell, A. J. Bruce, G. Nykolak, and J. Shmulovich, “Uniform upconversion in high-concentration Er3+-doped soda lime silicate and aluminosilicate glasses,” Opt. Lett. 22(11), 1468–1474 (1997). [CrossRef]

28.

E. Snoeks, G. N. Hoven, A. Polman, B. Hendriksen, M. B. J. Diemeer, and F. Priolo, “Cooperative upconversion in erbium-implanted soda-lime silicate glass optical waveguides,” J. Opt. Soc. Am. B 12(8), 1468–1474 (1995). [CrossRef]

29.

G. N. van den Hoven, E. Snoeks, A. Polman, C. van Dam, J. W. M. van Uffelen, and M. K. Smit, “Upconversion in Er-implanted Al2O3 waveguides,” J. Appl. Phys. 79(3), 1258–1266 (1996). [CrossRef]

OCIS Codes
(160.5690) Materials : Rare-earth-doped materials
(230.7370) Optical devices : Waveguides

ToC Category:
Optical Devices

History
Original Manuscript: November 16, 2010
Revised Manuscript: January 24, 2011
Manuscript Accepted: April 6, 2011
Published: April 18, 2011

Citation
Jee Soo Chang, In Yong Kim, Gun Yong Sung, and Jung H. Shin, "Population inversion and low cooperative upconversion in Er-doped silicon-rich silicon nitride waveguide," Opt. Express 19, 8406-8412 (2011)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-19-9-8406


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References

  1. See, for instance, “Silicon Photonics,”Topics in Applied Physics Vol. 94, edited by L. Pavesi and D. J. Lockwood (Springer, 2004). [PubMed]
  2. D. S. Gardner and M. L. Brongersma, “Microring and microdisk optical resonators using silicon nanocrystals and erbium prepared using silicon technology,” Opt. Mater. 27(5), 804–811 (2005). [CrossRef]
  3. N. Daldosso, M. Melchiorri, F. Riboli, M. Girardini, G. Pucker, M. Crivellari, P. Bellutti, A. Lui, and L. Pavesi, “Comparison among various Si3N4 waveguide geometries grown within a CMOS fabrication pilot line,” J. Lightwave Technol. 22(7), 1734–1740 (2004). [CrossRef]
  4. M. Melchiorri, N. Daldosso, F. Sbrana, L. Pavesi, G. Pucker, C. Kompocholis, P. Bellutti, and A. Lui, “Propagation loss of silicon nitride waveguides in the near-infrared range,” Appl. Phys. Lett. 86(12), 121111 (2005). [CrossRef]
  5. A. Gondarenko, J. S. Levy, and M. Lipson, “High confinement micron-scale silicon nitride high Q ring resonator,” Opt. Express 17(14), 11366–11370 (2009). [CrossRef] [PubMed]
  6. E. Shah Hosseini, S. Yegnanarayanan, A. H. Atabaki, M. Soltani, and A. Adibi, “Systematic design and fabrication of high-Q single-mode pulley-coupled planar silicon nitride microdisk resonators at visible wavelengths,” Opt. Express 18(3), 2127–2136 (2010). [CrossRef] [PubMed]
  7. S. Zheng, H. Chen, and A. W. Poon, “Microring-resonator cross-connect filters in silicon nitride: rib waveguide dimensions dependence,” IEEE J. Sel. Top. Quantum Electron. 12(6), 1380–1387 (2006). [CrossRef]
  8. J. S. Chang, K. Suh, M.-S. Yang, and J. H. Shin, “Development and application of Er-doped silicon-rich silicon nitrides and Er silicates for on-chip light sources,” “Silicon Photonics II,” Topics in Applied Physics Vol. 119, 95–130 (2011).
  9. L. Dal Negro, R. Li, J. Warga, and S. N. Basu, “Sensitized erbium emission from silicon-rich nitrides/silicon superlattice structures,” Appl. Phys. Lett. 92(18), 181105 (2008). [CrossRef]
  10. R. Li, S. Yerci, and L. Dal Negro, “Temperature dependence of the energy transfer from amorphous silicon nitride to Er ions,” Appl. Phys. Lett. 95(4), 041111 (2009). [CrossRef]
  11. S. Yerci, R. Li, S. O. Kucheyev, T. van Buuren, S. N. Basu, and L. Dal Negro, “Energy transfer and 1.54 µm emission in amorphous silicon nitride films,” Appl. Phys. Lett. 95(3), 031107 (2009). [CrossRef]
  12. J. S. Chang, S. C. Eom, G. Y. Sung, and J. H. Shin, “On-chip, planar integration of Er doped silicon-rich silicon nitride microdisk with SU-8 waveguide with sub-micron gap control,” Opt. Express 17(25), 22918–22924 (2009). [CrossRef]
  13. Y. Gong, M. Makarova, S. Yerci, R. Li, M. J. Stevens, B. Baek, S. W. Nam, R. H. Hadfield, S. N. Dorenbos, V. Zwiller, J. Vuckovic, and L. Dal Negro, “Linewidth narrowing and Purcell enhancement in photonic crystal cavities on an Er-doped silicon nitride platform,” Opt. Express 18(3), 2601–2612 (2010). [CrossRef] [PubMed]
  14. G. Y. Sung, N.-M. Park, J.-H. Shin, K.-H. Kim, T.-Y. Kim, K. S. Cho, and C. Huh, “Physics and device structures of highly efficient silicon quantum dots based silicon nitride light-emitting diodes,” IEEE J. Sel. Top. Quantum Electron. 12(6), 1545–1555 (2006). [CrossRef]
  15. S. Yerci, R. Li, and L. Dal Negro, “Electroluminescence from Er-doped Si-rich silicon nitride light emitting diodes,” Appl. Phys. Lett. 97(8), 081109 (2010). [CrossRef]
  16. W. J. Miniscalco, “Er-doped glasses for fiber amplifiers at 1500 nm,” J. Lightwave Technol. 9(2), 234–250 (1991). [CrossRef]
  17. K. Suh, M. Lee, J. S. Chang, H. Lee, N. Park, G. Y. Sung, and J. H. Shin, “Cooperative upconversion and optical gain in ion-beam sputter-deposited Er(x)Y(2-x)SiO(5) waveguides,” Opt. Express 18(8), 7724–7731 (2010). [CrossRef] [PubMed]
  18. G. N. van den Hoven, R. J. I. M. Koper, A. Polman, C. van Dam, J. W. M. van Uffelen, and M. K. Smit, “Net optical gain at 1.53 μm, in Er-doped Al2O3 waveguides on silicon,” Appl. Phys. Lett. 68(14), 1886–1888 (1996). [CrossRef]
  19. J. D. B. Bradley, L. Agazzi, D. Geskus, F. Ay, K. Wörhoff, and M. Pollnau, “Gain bandwidth of 80 nm and 2 dB/cm peak gain in Al2O3:Er3+ optical amplifiers on silicon,” J. Opt. Soc. Am. B 27(2), 187–196 (2010). [CrossRef]
  20. A. Polman, D. C. Jacobson, D. J. Eaglesham, R. C. Kistler, and J. M. Poate, “Optical doping of waveguide materials by MeV Er implantation,” J. Appl. Phys. 70(7), 3778–3784 (1991). [CrossRef]
  21. I. Y. Kim, J. H. Shin, and K. J. Kim, “Extending the nanocluster-Si/erbium sensitization distance in Er-doped silicon nitride: The role of Er-Er energy migration,” Appl. Phys. Lett. 95(22), 221101 (2009). [CrossRef]
  22. P. Pellegrino, B. Garrido, J. Arbiol, C. Garcia, Y. Lebour, and J. R. Morante, “Site of Er ions in silica layers codoped with Si nanoclusters and Er,” Appl. Phys. Lett. 88(12), 121915 (2006). [CrossRef]
  23. J. S. Chang, J.-H. Jhe, M.-S. Yang, J. H. Shin, K. J. Kim, and D. W. Moon, “Effects of silicon nanostructure evolution on Er3+ luminescence in silicon-rich silicon oxide/Er-doped silica multilayers,” Appl. Phys. Lett. 89(18), 181909 (2006). [CrossRef]
  24. S. Minissale, T. Gregorkiewicz, M. Forcales, and R. G. Elliman, “On optical activity of Er3+ ions in Si-rich SiO2 waveguides,” Appl. Phys. Lett. 89(17), 171908 (2006). [CrossRef]
  25. D. E. McCumber, “Theory of phonon-terminated optical masers,” Phys. Rev. 134(2A), A299–A306 (1964). [CrossRef]
  26. P. C. Becker, N. A. Olsson, and J. R. Simpson, Erbium-Doped Fiber Amplifiers: Fundamentals and Technology (Academic Press, 1997).
  27. M. P. Hehlen, N. J. Cockroft, T. R. Gosnell, A. J. Bruce, G. Nykolak, and J. Shmulovich, “Uniform upconversion in high-concentration Er3+-doped soda lime silicate and aluminosilicate glasses,” Opt. Lett. 22(11), 1468–1474 (1997). [CrossRef]
  28. E. Snoeks, G. N. Hoven, A. Polman, B. Hendriksen, M. B. J. Diemeer, and F. Priolo, “Cooperative upconversion in erbium-implanted soda-lime silicate glass optical waveguides,” J. Opt. Soc. Am. B 12(8), 1468–1474 (1995). [CrossRef]
  29. G. N. van den Hoven, E. Snoeks, A. Polman, C. van Dam, J. W. M. van Uffelen, and M. K. Smit, “Upconversion in Er-implanted Al2O3 waveguides,” J. Appl. Phys. 79(3), 1258–1266 (1996). [CrossRef]

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