8-mV threshold Er/sup 3+/-doped planar waveguide amplifier

Ghosh, Ruby N.; Shmulovich, J.; Kane, C.F.; Barros, M.R.X. de; Nykolak, G.; Bruce, A.J.; Becker, P. C.

doi:10.1109/68.491212

Cited by 62 publications

(22 citation statements)

References 6 publications

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“…Topographic guides have been formed in Er-doped silicate and phosphate glasses deposited by sputtering [5], [6]. Er-doped guides have also been formed by plasma-enhanced chemical vapor deposition (PECVD) [7], [8].…”

mentioning

confidence: 99%

Fiber-device-fiber gain from a sol-gel erbium-doped waveguide amplifier

Huang

Syms

Yeatman

et al. 2002

IEEE Photon. Technol. Lett.

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Abstract-An erbium-doped silica-on-silicon planar waveguide optical amplifier is described. The active core is a topographic guide formed from aluminophosphosilicate glass doped with erbium and ytterbium. The buffer is formed from silica deposited by thermal oxidation and the cladding from borophosphosilicate glass obtained by plasma-enhanced chemical vapor deposition. The use of low process temperatures allows relatively heavy doping and careful control of the core etching allows low background insertion losses to be obtained. Spontaneous emission and gain measurements are given and 5.4-dB fiber-device-fiber gain is demonstrated using a 5-cm-long chip pumped using a 980-nm laser diode at 175-mW pump power.Index Terms-Erbium, optical amplification, sol-gel, waveguides.T HE ERBIUM-DOPED fiber amplifier (EDFA) has been highly successful as a low-noise gain block at 1535-nm wavelength. Er-doped waveguide amplifiers (EDWAs) have also attracted attention, because of their potential for integration with pump lasers and filters [1]. The main difficulty in constructing an EDWA lies in providing suitably high gain in a short length, which requires high Er doping without concentration-dependent effects.Erbium-doped amplifiers and lossless splitters have been formed by ion exchange in silicate [2] at 980 nm, high pump powers are required. However, pump powers are reduced by codoping with Yb , which has a large cross section and which may transfer energy nonradiatively to the I level of Er . Although erbium may be incorporated in silica by PECVD, difficulties are caused by the low vapor pressure of erbium compounds. There is, therefore, a need to investigate alternative processes for depositing Er-doped silicate glasses, which can also incorporate the range of codopants needed to tailor the Er environment. One possibility is the sol-gel process. Thick layers of silicate glasses can be formed as multilayers, using repetitive cycles of spin-coating and rapid thermal annealing (SC-RTA), with careful control of the annealing temperature [9]. These layers may then be formed into buried channel guides by the conventional route of reactive ion etching and cladding.Early sol-gel guides were mainly based on TiO -SiO . However, TiO is unsuitable for sol-gel optics, because of its high process temperatures and tendency to form crystalline phases, including erbium titanate. Since then, improved guides have been developed using a range of dopants such as P O , B O , Al O , and Ga O . Some dopants have been used to control process temperatures in addition to altering the refractive index. Rare earth dopants such as Nb O , Er O , and Yb O have also been incorporated. Some progress has been made toward fabricating EDWAs by SC-RTA. For example, relative gains of 1.1 dB/cm have been obtained using Yb-Er-codoped silica-titania, but only in a striploaded geometry with fiber coupling and propagation losses so high that no external gain was observed [10]. In this letter, we demonstrate the first practical sol-gel EDWA. The device is based on a ...

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confidence: 99%

Fiber-device-fiber gain from a sol-gel erbium-doped waveguide amplifier

Huang

Syms

Yeatman

et al. 2002

IEEE Photon. Technol. Lett.

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“…A useable overall gain may be obtained using a straight waveguide layout [3]- [6]. Sputtered phosphate glasses show similar behavior [7], as do sputtered multicomponent glasses [8], [9] and ion implanted alumina [10]. Unfortunately, planar lightwave circuits (PLCs) based on many of these materials systems are currently incompatible with the low-cost low-loss fiber pigtailing methods widely used with silica-on-silicon PLCs.…”

Section: Introductionmentioning

confidence: 99%

Layout optimization for erbium-doped waveguide amplifiers

Lowe

Syms

Huang³

2002

J. Lightwave Technol.

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Abstract-The optical layout of erbium-doped waveguide amplifiers (EDWAs) based on spiral and folded spiral planar lightwave circuits is considered. It is shown that layouts may be ranked according to their ability to provide maximum gain within a given chip area and an optimum layout based on a spiral containing both straight and curved waveguide sections is identified from an initial set. The analysis is initially based on simple geometric principles. A detailed optical simulation is then carried out using an algorithm that links a five-level rate equation model with beam propagation by the method of lines. The results confirm the choice of optimum layout.Index Terms-Erbium-doped waveguide amplifier (EDWA), optical amplifier.

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“…EDWAs have been reported based on both FHD [3] and PECVD [6]. For the former, high levels of phosphorous co-doping were required, and Er concentrations were limited to under 0.5 wt.% [7].…”

Section: Formats For Edwasmentioning

confidence: 99%

Molecular homogeneity in erbium-doped sol-gel waveguide amplifiers

Laliotis

Yeatman

Ahmad

et al. 2004

IEEE J. Quantum Electron.

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Abstract-High net gain levels have recently been reported in silica-on-silicon waveguide amplifiers, using the sol-gel method of glass deposition. Spectroscopic measurements indicate that high inversion levels are achieved at high erbium concentrations, suggesting a high uniformity in the erbium distribution. Here we show that high inversion and low scattering losses are only achieved in sol-gel waveguides which have had restricted heat treatment and that both degrade upon additional annealing. Evolution of scattering loss spectra are presented, and these are included in a model of the ytterbium-sensitized waveguide amplifiers to show that the gain reduction with heat treatment is not wholly due to pump and signal excess losses, but also to changes in the spectroscopic properties of the erbium ions. In particular, the formation of clusters in which inversion is rapidly quenched is indicated. Thus, we show that the superior performance of the sol-gel method for rare-earth doping of silica waveguides, for amplifier and laser applications, results from its ability to form homogenous molecular structures which are meta-stable and which consequently cannot be formed in glasses that require high-temperature consolidation or annealing.

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8-mV threshold Er/sup 3+/-doped planar waveguide amplifier

Cited by 62 publications

References 6 publications

Fiber-device-fiber gain from a sol-gel erbium-doped waveguide amplifier

Fiber-device-fiber gain from a sol-gel erbium-doped waveguide amplifier

Layout optimization for erbium-doped waveguide amplifiers

Molecular homogeneity in erbium-doped sol-gel waveguide amplifiers

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