Variable optical attenuator
AssigneeJDS Uniphase Corporation
InventorsMart Diemeer, Peter Edwin Sportel
Life of this patent
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Abstract
The invention provides a variable optical attenuator or array with low PDL by using an embedded polymer channel waveguide with a plurality of resistive heaters fabricated on the top cladding of the polymer waveguide. The resistive heaters create a strong thermal gradient in the polymer layer stack which is associated with a strong refractive index gradient with the lowest refractive index under the heater. This refractive index gradient causes the optical mode in the channel to shift towards the buffer layer. Attenuation is induced by transition losses between heated and unheated regions in the polymer waveguide when an optical signal passes through these regions of the polymer waveguide.
Claims24
A variable optical attenuator comprising:
- a substrate;
- a polymeric waveguide having a core surrounded by a cladding, the waveguide being supported on the substrate;
- and
- at least two refractive index varying means disposed in-line and spaced apart on an external surface of the waveguide along a propagation direction of an optical signal passing through the waveguide for generating a substantially localized refractive index gradient such that the optical signal propagating through the waveguide passes through a plurality of substantially localized varying refractive index regions for generating a transition loss to attenuate the optical signal by causing a shift of a mode field of the optical signal.
A variable optical attenuator comprising:
- a substrate of a heat absorbing material;
- a polymeric waveguide having a polymeric core disposed within a polymeric cladding upon the substrate;
- and
- at least two temperature varying means spaced apart along the polymeric waveguide for one of increasing and decreasing the temperature of said waveguide for generating a substantially localized refractive index gradient in the waveguide near the temperature varying means to shift a mode field of an optical signal propagating through said polymeric waveguide to cause a transition loss of the optical signal for attenuating the optical signal, said refractive index gradient being substantially localized in a propagation direction of the optical signal.
Dependencies are inferred from the claim text.