Patent ID: 11971590
Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 6:
7. Optical coupling method for an optical integrated circuit comprising at least an input waveguide, and a plurality of branching circuits including at least two stages being connected in series in a tree shape and optically connected to the input waveguide, wherein at least a part of the plurality of branching circuits on a last stage comprises at least two arm waveguides and configures a Mach-Zehnder interferometer (MZI) arranged in parallel,
the method comprising:
measuring a sum of optical power of light propagating along an equal number of the arm waveguides selected respectively from a first waveguide group and a second waveguide group, one branched light from the branching circuit on a first stage propagating along the arm waveguides of the at least two arm waveguides of the first group, another branched light from the branching circuit on the first stage propagating along the arm waveguides of the at least two arm waveguides of the second group;
changing an optical focusing spot position to the input waveguide, such that the sum of the optical power is maximized; and
determining a position of an optical component injecting light to the input waveguide with respect to the optical integrated circuit.