One aspect relates to a method for the manufacture of doped quartz glass. Moreover, one aspect relates to quartz glass obtainable according to the method including providing a soot body, treating the soot body with a gas, heating an intermediate product and vitrifying an intermediate product.

Hollow ingots of transparent synthetic vitreous silica glass of external diameter greater than 400 mm and internal diameter greater than 300 mm are disclosed. The ingots are substantially free from bubbles or inclusions greater than 100 m in diameter, have no more than 100 ppB of any individual metallic impurity, and have chlorine concentration less than 5 ppM. Also disclosed are methods for producing such ingots, in which a porous soot body of density greater than 0.4 g/cm.sup.3 is deposited on an oxidation resistant mandrel. The soot body is dehydrated on a mandrel comprising graphite, carbon fiber reinforced carbon, silicon carbide, silicon impregnated silicon carbide, silicon carbide-coated graphite or vitreous silica, either under vacuum or in the presence of a reducing gas, and then sintered to transparent pore-free glass under vacuum or in an atmosphere of helium.

Proportions of the element erbium, the element aluminum, and the element phosphorus are adjusted during optical fiber preparation so that aluminum phosphate is formed around the element erbium in a prepared optical fiber, a probability that the element erbium in the optical fiber transits to a high energy level is reduced, and an excited-state absorption effect of the element erbium in the optical fiber on an optical signal is suppressed.

There is provided a photonics device including: a doped material including an oxide host hosting a system of ytterbium oxide and network modifiers, containing above 0.510.sup.26 ions/m.sup.3 of ytterbium; a laser pump directed to the doped material; and the lifetime of an excited state of the ytterbium in response to the laser pump is of above 0.9 ms and a phonon energy of the host material is above 1000 cm.sup.1.