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Routinely used erbium crystal lasers operate at the 3-μm spectral range. In the silica fibers the transparency window corresponds to the eye-safe range of 1.5-μm. The 4I13/2 -4I15/2 transition provides the lasing at this range in a glass matrix. However, in crystals it is of negligibly small intensity. To significantly intensify this transition, the (Gd,Y)3(Ga,Sc)5O12:Er3+ crystal has been chosen as the basis for the new laser crystal that is able to operate at 1.5-μm. The single crystal garnet films with thickness up to 18-μm were grown, using the method of liquid-phase epitaxy on the Gd3Ga5O12 substrates. The 20-mol% maximal concentration of Er3+ ions was achieved without luminescence quenching. The up-conversion processes were blocked by the addition of the Fe-ions sensitizer. As a result, at the same level of absorbed pumping power the luminescence intensity at the 1.5-μm band for the specially doped film was approximately two orders of magnitude higher than that compared with the crystal of the traditional content. The spectral width achieved with a new medium is a little smaller than 300 nm, which makes this crystal convenient for the femtosecond laser design. The laser tunable inside this range may provide hundreds of the optical channels for telecommunication or optical computer devices.
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