Variable optical attentuator (VOA) having an absorber for receiving residual light outputfrom the VOA
AssigneeInfinera Corporation
InventorRadhakrishnan L. Nagarajan
Life of this patent
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Abstract
A variable optical attenuator (VOA), which may include a Mach-Zehnder interferometer, is configured such that a substantial part of an input signal is output on a first waveguide, and a relatively small part of the input signal may be output on a second waveguide due to manufacturing process variations and/or other non-idealities. Such residual or extraneous light may interfere with light in the first waveguide, especially if the VOA is integrated on substrate. Accordingly, consistent with an aspect of the present disclosure, a photodiode may be provided to receive and absorb the residual light, thereby minimizing interference or cross-talk with light in the first waveguide.
Claims8
An optical device, comprising:
- an input waveguide configured to receive an optical signal;
- a first coupler receiving the optical signal from the input waveguide;
- a first branch waveguide configured to receive a first portion of the optical signal from the coupler;
- a second branch waveguide configured to receive a second portion of the optical signal from the coupler;
- a second coupler receiving the first and second portions of the optical signal from the first and second branch waveguides, respectively;
- a first output waveguide, the second coupler being configured to combine first parts of the first and second portions of the optical signal onto the first output waveguide, the first parts of the first and second portions of the optical signal constituting a first combined signal;
- a second output waveguide, the second coupler further being configured to combine second parts of the first and second portions of the optical signal onto the second waveguide, the second parts of the first and second portions of the optical signal constituting a second combined signal;
- and
- a photodiode configured to receive the second combined signal.
Dependencies are inferred from the claim text.