Demonstration of ErSiO superlattice crystal waveguide toward optical amplifiers and emitters
✍ Scribed by Isshiki, H. ;Ushiyama, T. ;Kimura, T.
- Book ID
- 105364673
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 170 KB
- Volume
- 205
- Category
- Article
- ISSN
- 0031-8965
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✦ Synopsis
Abstract
ErSiO superlattice crystal (SC) waveguide is demonstrated. ErSiO‐SC film was formed on a SiO~2~/Si substrate. After the ErSiO preform formation by sol–gel method, high temperature anneal for the crystallization was performed in Ar atmosphere. Then the ErSiO‐SC layer thickness is 220 nm. Then refractive index of ErSiO‐SC was estimated to be 1.8 by ellipsometry and reflection spectroscopy measurements. To obtain the lateral optical confinement, polymer cladding layer (n = 1.54) was coated on the ErSiO‐SC film and the strip‐loaded structures with 5 μm width were formed by focused ion beam (FIB) etching. The optical confinement factor Γ of the ErSiO‐SC waveguide layer was estimated to be 0.42, assuming the lateral confinement factor was 1 because of the sufficient wide waveguide for the light. Optical pumping was performed by using a 1480 nm laser diode through the lensed fiber. The pumping power is 30 mW at the fiber input. Green light emissions corresponding to 4f intra‐shell transitions from ^4^S~3/2~ and ^2^H~11/2~ to ^4^I~15/2~ in the Er^3+^ ions, indicating cooperative upconversion in the ErSiO‐SC waveguide, can be observed by using a conventional CCD system at room temperature. The upconversion emission behaviour through the waveguide with a photon trap for the 1480 nm light reveals that the 1480 nm pumping light is well‐confined into the waveguide. The cooperative upconversion as the gain limitting factor in the ErSiO‐SC waveguide are discussed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)