Stress free and thermally stabilized dielectric fiber

11) A process for making a multilayer interference filter having substantially reduced net stress, the process comprising the steps of:

• a) providing a first substrate,
• b) depositing a removable multilayer interference filter having a net stress greater than 50 MPa over said first substrate,
• c) removing the multilayer interference filter from the first substrate to form a free standing filter,
• d) removing the multilayer interference filter from the first substrate whereby the net stress is reduced to less than 50% of the initial net stress.

17) A multilayer optical interference filter comprising:

• a) a least two optical cavities,
• i) the cavities having an optical thickness that results in a passband region with a center wavelength of between 1 and 2 microns;
• b) a dielectric reflector stack comprising an alternating sequence of 2 or more layer of a material with a first refractive index and a second material with a higher refractive index,
• c) said filter having at least a central region that is unsupported by a substrate and substantially free of stress.

19) A method of separating optical communication signal channel, the method comprising:

• a) providing at least one optical waveguide,
• b) providing an optical element selected from the group consisting of second output waveguide, a detector, a transmitter, and an optical modular,
• c) disposing between the input waveguide and the output waveguide a filter assembly, the filter assembly comprising;
• i) a frame member having a first planar surface that substantially surrounds a central opening therein,
• ii) an multilayer interference filter having a first surface attached to the planar surface of said frame member to define an unobstructed optical aperture through said multilayer interference filter,
• d) whereby at least one optical signal channel of a first characteristic wavelength is transmitted through the optical aperture of the filter assembly on passage between the optical waveguide and the optical element and a co-propagating optical signal is reflected by the multilayer interference filter.