Temperature stable bragg grating package with post tuning for accurate setting of centre frequency

Abstract

A method of accurately setting the center wavelength of a fiber grating fixed in a temperature compensation package, the method comprising the steps of: fixing the grating to the package and altering the size of the package in a post processing step. The altering step can comprise elongating or compressing the package so as to substantially permanently alter the size of the package. The temperature compensation package can comprise: a first elongated member having a first coefficient of thermal expansion; two second elongated members, one each attached to the ends of the first elongated member and having their other second ends closer together than the ends of the first elongated member, the second elongated members having a second coefficient of thermal expansion relatively more than the first coefficient of thermal expansion; and two material matching members attached to the second ends and adapted to provide for material matching fixing mixtures to the second elongated members; the fixing mixtures to the second elongated members; the fixing mixtures fixing ends of the fiber grating to the temperature compensation package. The fixing mixture can comprise glass of metal solder. The material matching members are preferably located within an aperture in the second ends.