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

Claim 2:
3. The method according to claim 2, wherein
the optical integrated circuit further comprising:
at least one stage of a plurality of 1×2 branching circuits being connected in series to the 1×2 branching circuit; and
corresponding waveguides respectively connected to output ports of the plurality of 1×2 branching circuits at a latter stage; and
the measuring comprises measuring a sum of photocurrents of an equal number of the corresponding waveguides selected respectively from a first waveguide group and a second waveguide group, one branched light from the 1×2 branching circuit on a first stage propagating along the corresponding waveguides of the first waveguide group, another branched light from the 1×2 branching circuit on the first stage propagating along the corresponding waveguides of the second waveguide group.