Abstract: A laser initiated process generates a shock wave of sufficient strength to produce a sintered product. The sintered product is prepared from at least a fuel and an oxidizer that will sustain an explosion in a reaction vessel. The explosion is initiated by introducing a laser beam into the reaction vessel and a shock wave begins to propagate at the point where the explosion is initiated. A sintered product is prepared when the shock wave is sufficiently strong to densify the product. Although the reaction will proceed using a two-component fuel-oxidizer mixture, the reaction is especially useful for producing sintered doped or undoped silicon dioxide (SiO.sub.2) from a reaction mixture containing at least silicon tetrachloride, hydrogen and oxygen. The sintered SiO.sub.2 can be deposited on a deposition surface situated in the reaction vessel to produce a preform that can be processed to produce an optical fiber.