Benzocyclobutene polymer (BCB) as a passivation layer for optical passive elements
AssigneeInfinera Corporation
InventorsCharles H. Joyner, Mark J. Missey, Radhakrishnan L. Nagarajan, Fred A. Kish, Jr.
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Abstract
An InP-based photonic integrated circuit (PIC) includes an optical passive element in the circuit with no bias current applied to such an element. A passivation cladding layer overlies a surface of the optical passive element where the passivation layer comprises benzocyclobutene polymer or BCB.
Claims10
An InP-based photonic integrated circuit (PIC) comprising an optical passive element, said optical passive element having no bias current applied to operate said element, a passivation, low stress cladding layer overlying a surface of the optical passive element, said passivation layer comprising a benzocyclobutene polymer (BCB) having a refractive index sufficient to reduce insertion loss of the optical passive element by minimizing a refractive index step existing between the optical passive element and adjacent waveguide structures;
- and an intermediate dielectric layer formed on said optical passive element surface and sandwiched between said surface and said BCB passivation layer.
An InP-based photonic integrated circuit (PIC) comprising:
- InP-based combiner/decombiner optical passive device having a plurality of optical ridge waveguides with at least one optical free space region fabricated with a lower refractive index InP cladding layer covering a higher refractive index InP-based waveguide core;
- a passivation layer overlying an air-exposed surface of the device;
- the passivation layer selected from the group consisting of BGB (n˜1.6), ZnS (n˜2.2), and ZnSe (n˜2.4) that have an intermediate refractive index between the refractive index of InP (n˜3.3) and the refractive index of air (n=1);
- the intermediate refractive index passivation layer reducing waveguide insertion loss of the device caused by optical scattering losses optical ridge waveguides by minimizing the refractive index step between the device InP cladded ridge waveguides and air.
Dependencies are inferred from the claim text.