# US 9,520,938 B2 · Optical transmitting device, fault determining method and fault diagnosis system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,520,938 B2 - Document ID: US9520938B2 - Status: Granted - Kind: B2 - Application number: 14/682,449 - Filed: 2015-04-09 - Published: 2015-12-17 - Granted: 2016-12-13 - Earliest claimed: 2014-06-12 - Assignees: Fujitsu Limited - Applicants: Fujitsu Limited - Inventors: Tsutomu Tsurumi - Web page: https://patentgrep.com/patent/US9520938B2 ## CPC - H04B 10/07955: {Monitoring or measuring power} - H04B 10/0799: {Monitoring line transmitter or line receiver equipment} - H04B 10/50: Transmitters - H04B 10/5057: {using a feedback signal generated by analysing the optical output} - H04B: TRANSMISSION ## Abstract An optical transmitting device includes: a light source; an optical modulator configured to modulate light from the light source based on an electric signal corresponding to transmission data, and output an optical signal based on the electric signal; a measuring section configured to measure power of the optical signal in each of measurement bands which are different from with each other and narrower than a frequency band of the modulated optical signal; a determining section configured to determine whether or not the measured power is within a power range in each of the measurement bands; and an output section configured to output fault information indicating a fault in the optical modulator when the measured power is not within the power range. ## Claims ### Claim 1 An optical transmitting device comprising: a light source; an optical modulator configured to modulate light from the light source based on an electric signal corresponding to transmission data, and output an optical signal based on the electric signal; a measuring section configured to measure power of the optical signal in each of measurement bands which are different from with each other and narrower than a frequency band of the modulated optical signal; a determining section configured to determine whether or not the measured power is within a power range in each of the measurement bands; and an output section configured to output fault information indicating a fault in the optical modulator when the measured power is not within the power range. ### Claim 2 (depends on 1) The optical transmitting device according to claim 1, wherein when the measured power is not within the power range, the output section outputs band information on the measurement band of the measured power together with the fault information. ### Claim 3 (depends on 1) The optical transmitting device according to claim 1, wherein the measuring section includes: a tunable filter capable of changing a wavelength band to be passed; and a photoelectric conversion element configured to output a signal corresponding to the power of the optical signal from the tunable filter. ### Claim 4 (depends on 3) The optical transmitting device according to claim 3, further comprising: a control section configured to measure the power based on the signal output by the photoelectric conversion element in each of the measurement bands while changing the wavelength band of the tunable filter. ### Claim 5 (depends on 3) The optical transmitting device according to claim 3, further comprising: an analog to digital converter configured to convert the signal output by the photoelectric conversion element into a digital signal. ### Claim 6 (depends on 1) The optical transmitting device according to claim 1, further comprising: a retaining section configured to retain a reference value of power in each of the measurement bands in association with a modulation system. ### Claim 7 (depends on 6) The optical transmitting device according to claim 6, wherein the determining section sets the power range in each of the measurement bands based on the reference value. ### Claim 8 (depends on 1) The optical transmitting device according to claim 1, further comprising a power adjusting section configured to adjust power of the light emitted by the light source based on the power of the optical signal. ### Claim 9 (depends on 8) The optical transmitting device according to claim 8, wherein the power adjusting section adjusts the power of the light emitted by the light source based on a total value of the measured power in each of the measurement bands. ### Claim 10 A fault determining method comprising: modulating light from a light source based on an electric signal corresponding to transmission data, and outputting an optical signal by an optical modulator; measuring power of the optical signal in each of measurement bands which are different from with each other and narrower than a frequency band of the optical signal; determining whether or not the measured power is within a power range in each of the measurement bands; and outputting information indicating a fault in the optical modulator when the measured power is not within the power range. ### Claim 11 (depends on 10) The fault determining method according to claim 10, further comprising: outputting band information on the measurement band of the measured power together with the fault information when the measured power is not within the power range. ### Claim 12 (depends on 10) The fault determining method according to claim 10, further comprising: retaining a reference value of power in each of the measurement bands in association with a modulation system. ### Claim 13 (depends on 12) The fault determining method according to claim 12, further comprising: Setting the power range in each of the measurement bands based on the reference value. ### Claim 14 (depends on 11) The fault determining method according to claim 11, further comprising: adjusting power of the light emitted by the light source based on the power of the optical signal. ### Claim 15 (depends on 11) The fault determining method according to claim 11, further comprising: adjusting the power of the light emitted by the light source based on a total value of the power measured in each of the measurement bands. ### Claim 16 A fault diagnosis system comprising: a light source; an optical modulator configured to modulate light from the light source based on an electric signal corresponding to transmission data, and output an optical signal based on the electric signal; a measuring section configured to measure power of the optical signal in each of different measurement bands which are different from with each other and narrower than a frequency band of the modulated optical signal; and a processor configured to process the measured power; the processor performs operations of: determining whether or not the measured power is within a power range in each of the measurement bands, and outputting fault information indicating a fault in the optical modulator when the measured power is not within the power range. ### Claim 17 (depends on 16) The fault diagnosis system according to claim 16, wherein the processor outputs band information on the measurement band of the measured power together with the fault information when the measured power is not within the power range. ### Claim 18 (depends on 16) The fault diagnosis system according to claim 16, wherein the processor retains a reference value of power in each of the measurement bands in association with a modulation system in a retaining section. ### Claim 19 (depends on 18) The fault diagnosis system according to claim 18, wherein the processor sets the power range in each of the measurement bands based on the reference value. ### Claim 20 (depends on 16) The fault diagnosis system according to claim 16, wherein the processor adjusts power of the light emitted by the light source based on the power of the optical signal.