Optical combiner and laser apparatus

An optical combiner comprising:

• a plurality of first input optical fibers that each include a core;
• a bridge fiber that includes:
• a bridge input surface including a single core, the single core being optically connected to all of the cores of the plurality of first input optical fibers;
• a diameter reduction portion having a diameter that decreases away from the bridge input surface along an optical axis of the optical combiner;
• and
• a bridge output surface located opposite to the bridge input surface along the optical axis;
• an intermediate optical fiber that includes a core connected to the bridge output surface of the bridge fiber;
• a second input optical fiber that includes a core;
• and
• an output optical fiber that includes:
• a first optical waveguide connected to the core of the intermediate optical fiber;
• and
• a second optical waveguide connected to the core of the second input optical fiber.