Erbium-doped planar optical device

Claim 1

An optical device, comprising: a) an elongate, active glass core which extends along a longitudinal axis and comprises silicon, oxygen, and erbium, the erbium being at least partially in the form of Er 3+ ions, the active core having a refractive index greater than about 1.5 at 633 nm; b) a glass cladding comprising at least one layer which at least partially surrounds the active core and has a refractive index which is smaller than the core refractive index; c) means for coupling signal radiation, having a signal wavelength, into the active core and means for coupling the signal radiation out of the active core; and d) means for coupling pump radiation into the active core such that pump radiation of an appropriate wavelength will excite at least some of the Er 3+ ions to a lasing level, leading to amplification of the signal radiation by stimulated emission, CHARACTERIZED IN THAT e) the device further comprises a substrate having a substantially planar principal surface; f) the active core is a body that overlies a portion of the principal surface; g) the cladding comprises a lower cladding layer disposed between the active core and the principal surface, and an upper cladding layer which overlies and partially surrounds the active core; h) the active core further comprises modifier comprised of at least two elements, one of which is selected from the group consisting of the Group IIIB, Group IVB and Group IIIA metals from the Mendeleef Periodic Table in an effective quantity to prevent clustering of erbium atoms and wherein none of the modifier elements are alkali metal or alkaline earth metals; i) the active core has an erbium-to-silicon atomic ratio of at least about 0.005 and an absolute erbium concentration of at least about 0.5×10 20 atoms per cubic centimeter; and j) the lasing level has a radiative lifetime of at least about 5 ms.