Optical fiber leakage loss measurement method
First Claim
1. A method for measuring a leakage loss in a multi-core optical fiber having a plurality of cores comprised of silica-based glass, a common cladding comprised of silica-based glass, and a resin coating, the common cladding having a lower refractive index than each of the plurality of cores and surrounding respective outer peripheries of the plurality of cores, the resin coating being provided on an outer periphery of the common cladding and having a higher refractive index than the common cladding, the method comprising:
- a first measurement step including;
inputting measurement light from one end of a peripheral core, among the plurality of cores of the multi-core optical fiber in a high refractive-index state in which the multi-core optical fiber is provided with the resin coating;
receiving the measurement light outputted from the other end of the peripheral core; and
measuring first transmission power of the measurement light propagated through the peripheral core; and
a second measurement step including;
after the measurement of the first transmission power, providing a low-refractive-index layer having a lower refractive index than the common cladding onto the outer periphery of the common cladding instead of all of the resin coating or part of a predetermined zone of the resin coating to set the multi-core optical fiber to a low-refractive-index state;
inputting the measurement light from the one end of the peripheral core of the multi-core optical fiber in the low refractive-index state;
receiving the measurement light outputted from the other end of the peripheral core;
measuring second transmission power of the measurement light propagated through the peripheral core; and
calculating, as the leakage loss, a power difference between the first transmission power and the second transmission power of the measurement light.
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Abstract
The present embodiment relates to a method of directly measuring a leakage loss from a peripheral core in a MCF with a coating to the coating. In the measurement method, in a high refractive-index state in which the coating is present on an outer periphery of a common cladding, first transmission power of measurement light, which propagates through the peripheral core of the MCF, is measured. On the other hand, in a low refractive-index state in which a low-refractive-index layer with a lower refractive index than the common cladding is provided on the outer periphery of the common cladding, second transmission power of the measurement light, which propagates through the peripheral core of the MCF, is measured. The leakage loss LL from the peripheral core to the coating is calculated as a difference between the first transmission power and the second transmission power.
8 Citations
6 Claims
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1. A method for measuring a leakage loss in a multi-core optical fiber having a plurality of cores comprised of silica-based glass, a common cladding comprised of silica-based glass, and a resin coating, the common cladding having a lower refractive index than each of the plurality of cores and surrounding respective outer peripheries of the plurality of cores, the resin coating being provided on an outer periphery of the common cladding and having a higher refractive index than the common cladding, the method comprising:
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a first measurement step including; inputting measurement light from one end of a peripheral core, among the plurality of cores of the multi-core optical fiber in a high refractive-index state in which the multi-core optical fiber is provided with the resin coating; receiving the measurement light outputted from the other end of the peripheral core; and measuring first transmission power of the measurement light propagated through the peripheral core; and a second measurement step including; after the measurement of the first transmission power, providing a low-refractive-index layer having a lower refractive index than the common cladding onto the outer periphery of the common cladding instead of all of the resin coating or part of a predetermined zone of the resin coating to set the multi-core optical fiber to a low-refractive-index state; inputting the measurement light from the one end of the peripheral core of the multi-core optical fiber in the low refractive-index state; receiving the measurement light outputted from the other end of the peripheral core; measuring second transmission power of the measurement light propagated through the peripheral core; and calculating, as the leakage loss, a power difference between the first transmission power and the second transmission power of the measurement light. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification