Patent ID: 6970635

Claim:
A method of setting an apparent optical length of a multiplicity of optical fibers for a given optical wavelength, comprising the steps of: (a) trimming the multiplicity of optical fibers to a substantially uniform actual length approximating a desired actual length; (b) launching a monochromatic beam of light into one end of each of the multiplicity of trimmed optical fibers and determining an arrival phase angle imparted by each of the multiplicity of trimmed optical fibers to the monochromatic beam over the actual length of each of the multiplicity of trimmed optical fibers; (c) comparing the determined arrival phase angle with a reference value representing a desired arrival phase shift angle; and (d) heating each of the multiplicity of trimmed optical fibers selectively to vary a refractive index thereof in response to comparison of the determined arrival phase angle with the reference value to change the arrival phase angle so as to set a desired apparent length of each of the multiplicity of trimmed optical fibers.