Spatial-mode optical power measurement method and apparatus
AssigneeSumitomo Electric Industries, Ltd.
InventorsTetsuya Hayashi, Tetsuya Nakanishi
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Abstract
Light output from a light source is distributed to intensity modulators that are associated with different spatial modes and that have different modulation conditions. An operation for receiving modulated light from each of the intensity modulators is performed for SDM fibers of different lengths while the light source is in operation, and pieces of optical power information are determined for respective spatial modes to be measured, from difference information regarding the lengths and the received optical powers.
Claims12
An optical power measurement method for measuring optical powers for respective spatial modes in a measurement-target optical fiber in which M spatial modes are transmittable, where M is greater than or equal to 2, the optical power measurement method comprising:
- a modulating step of individually modulating M light beams using different modulation conditions and generating M modulated light signals;
- an input step of inputting the M modulated light signals to the measurement-target optical fiber from a first end of the measurement-target optical fiber to cause the M modulated light signals to transmit in the respective M spatial modes;
- a light-receiving step of collectively receiving output beams from a second end of the measurement-target optical fiber without distinguishing between the spatial modes and converting optical power of the output beams collectively received into a first electric signal, the second end of the measurement-target optical fiber opposing the first end of the measurement-target optical fiber, the first electric signal being analog data or digital data;
- and
- an optical power obtaining step of analyzing the first electric signal and obtaining, as pieces of optical power information for the respective M modulated light signals, optical powers Pm (m=1, 2, . . . , M) for the respective M spatial modes output from the second end of the measurement-target optical fiber.
A spatial-mode optical power measurement apparatus comprising:
- a light source;
- a splitter that splits light from the light source into a number of beams, the number of beams is equal to M that represents the number of two or more spatial modes to be measured;
- a spatial mode input device including:
- a plurality of modulators that modulate the respective beams obtained by the splitter using different modulation conditions and that generate M modulated light signals,
- input ends to which the respective M modulated light signals are separately input, and
- an output end from which the M modulated light signals are output to a measurement-target optical fiber in which M spatial modes are transmittable;
- a photoelectric converter that collectively receives output signals of the spatial mode input device via the measurement-target optical fiber and converts optical power of the output signals collectively received into a first electric signal, the first electric signal being analog data or digital data;
- and
- an optical power information obtaining unit including a first calculator that performs a method comprising:
- analyzing the first electric signal;
- and
- measuring, as pieces of optical power information for the respective M modulated light signals, optical powers Pm (m=1, 2, . . . , M) for the respective M spatial modes output from the measurement-target optical fiber.
Dependencies are inferred from the claim text.