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  <xs:element id="cien_PropertyPlantAndEquipmentFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortizationAndOperatingLeaseRightOfUseAsset" abstract="false" name="PropertyPlantAndEquipmentFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortizationAndOperatingLeaseRightOfUseAsset" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cien_TermLoan2030Member" abstract="true" name="TermLoan2030Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="cien_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteAgeReached" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteAgeReached" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="cien_InstallationAndDeploymentMember" abstract="true" name="InstallationAndDeploymentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="cien_LongTermInvestmentsFairValueDisclosure" abstract="false" name="LongTermInvestmentsFairValueDisclosure" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cien_AttMember" abstract="true" name="AttMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="cien_AmortizationOfIntangibleAssetsExcludingAmortizationIncludedInPropertyPlantAndEquipment" abstract="false" name="AmortizationOfIntangibleAssetsExcludingAmortizationIncludedInPropertyPlantAndEquipment" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cien_GlobalServicesMember" abstract="true" name="GlobalServicesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="cien_StockRepurchasedDuringPeriodSharesPurchasedForTaxWithholdingsForShareBasedCompensationValue" abstract="false" name="StockRepurchasedDuringPeriodSharesPurchasedForTaxWithholdingsForShareBasedCompensationValue" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cien_FiniteLivedIntangibleAssetExpectedAmortizationAfterYearFour" abstract="false" name="FiniteLivedIntangibleAssetExpectedAmortizationAfterYearFour" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cien_StockRepurchasedDuringPeriodSharesPurchasedForTaxWithholdingsForShareBasedCompensationShares" abstract="false" name="StockRepurchasedDuringPeriodSharesPurchasedForTaxWithholdingsForShareBasedCompensationShares" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="cien_MaintenanceSupportAndTrainingMember" abstract="true" name="MaintenanceSupportAndTrainingMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="cien_CapitalizedContractAcquisitionCostsMember" abstract="true" name="CapitalizedContractAcquisitionCostsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="cien_BluePlanetAutomationSoftwareandServicesMember" abstract="true" name="BluePlanetAutomationSoftwareandServicesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="cien_ConsultingAndNetworkDesignMember" abstract="true" name="ConsultingAndNetworkDesignMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="cien_SeniorNotes400Due2030Member" abstract="true" name="SeniorNotes400Due2030Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="cien_UnbilledAccountsReceivablesMember" abstract="true" name="UnbilledAccountsReceivablesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="cien_ShareBasedCompensationArrangementByShareBasedPaymentAwardRetirementNoticePeriod" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardRetirementNoticePeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="cien_BusinessCombinationConsiderationTransferredExcludingAdditionalContingentConsideration" abstract="false" name="BusinessCombinationConsiderationTransferredExcludingAdditionalContingentConsideration" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cien_NewTermLoan2025Member" abstract="true" name="NewTermLoan2025Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="cien_NoncashGainLossFromCostMethodEquityInvestment" abstract="false" name="NoncashGainLossFromCostMethodEquityInvestment" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cien_CumulativeSharesRepurchasedExcludingSharesPurchasedForTaxWithholdingsForShareBasedCompensationWeightedAveragePricePerShare" abstract="false" name="CumulativeSharesRepurchasedExcludingSharesPurchasedForTaxWithholdingsForShareBasedCompensationWeightedAveragePricePerShare" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType"/>
  <xs:element id="cien_RoutingAndSwitchingMember" abstract="true" name="RoutingAndSwitchingMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="cien_CustomersAbove10ThresholdMember" abstract="true" name="CustomersAbove10ThresholdMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="cien_TermLoan2025Member" abstract="true" name="TermLoan2025Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="cien_PlatformSoftwareandServicesMember" abstract="true" name="PlatformSoftwareandServicesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
</xs:schema>
