光纤通信发展历程与现状

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光纤通信讲座光纤通信发展概述.ppt的资源摘要信息主要涵盖了光纤通信的历史发展、关键技术进步以及当前的国内外状况。以下是对这些知识点的详细说明: 光纤通信的早期阶段始于19世纪末,当时的光通信方式主要是利用光波作为载体,如贝尔的光电话,但这受限于大气传播条件,效率和稳定性较低。真正推动光通信发展的是1960年代激光器的发明,特别是红宝石激光器的出现,使得光通信进入了新的时代。尽管初期的光通信在大气中进行试验,但由于传输介质的问题,如损耗大、稳定性差,研究进入了低潮。 转折点发生在1966年,高锟博士与霍克哈姆提出光纤通信的概念,他们指出通过提纯原材料和改进工艺可以制造出低损耗光纤。这一理论奠定了现代光纤通信的基础,并最终在1970年代取得了重大突破,美国康宁公司成功研制出损耗较低的光纤。 光纤通信的主要部件包括光源(如激光器和LED)、光纤(芯、包层结构)、耦合器、光检测器等。随着技术的进步,光纤的损耗不断降低,传输容量大幅度提升,从最初的单模光纤到后来的多模光纤,再到现在的色散管理光纤,光纤通信系统不断演进,能够实现超高速率、超长距离的信息传输。 光纤通信系统的发展历程也反映了技术的革新,从早期的模拟传输到数字传输,从简单的点对点系统到复杂的光网络系统,如SDH、WDM、ASON等,这些技术使得光通信在长途通信、城域网、接入网等多个领域得到广泛应用。 国内外光纤通信的发展现状呈现出多元化和智能化的趋势。在中国,光纤宽带网络的普及率不断提升,4G/5G移动通信网络的建设大量采用光纤,推动了光纤到户(FTTH)的快速发展。而在国际上,海底光缆系统的建设和升级,以及数据中心间的高速互联,都离不开光纤通信。此外,光纤通信还与云计算、物联网、大数据等新兴技术紧密关联,为信息化社会提供了强大的基础设施支持。 未来,光纤通信将继续向更高的带宽、更低的延迟、更智能的网络管理方向发展,如100Gbps、400Gbps甚至Tbps级别的传输速率,以及灵活的光网络资源调度。同时,光纤通信还将深入到更多的应用场景,如无人驾驶、远程医疗等领域,进一步推动信息社会的进程。

SELECT PIS.SHOW_FLT_DETAIL AS SHOW_FLT_DETAIL -- new , PIS.SHOW_AWB_DETAIL AS SHOW_AWB_DETAIL -- new , PIS.DISPLAY_AIRLINE_CODE AS CARRIER_CODE , DECODE(PIS.REVERT_FLOW,'N',PIS.FLOW_TYPE,DECODE(PIS.FLOW_TYPE,'I','E','I')) AS FLOW_TYPE , PIS.SHIP_TO_LOCATION AS SHIP_TO_LOCATION , PIS.INVOICE_SEQUENCE AS INVOICE_SEQUENCE , PFT.FLIGHT_DATE AS FLIGHT_DATE , PFT.FLIGHT_CARRIER_CODE AS FLIGHT_CARRIER_CODE , PFT.FLIGHT_SERIAL_NUMBER AS FLIGHT_SERIAL_NUMBER , PFT.FLOW_TYPE AS AIRCRAFT_FLOW , FAST.AIRCRAFT_SERVICE_TYPE AS AIRCRAFT_SERVICE_TYPE , PPT.AWB_NUMBER AS AWB_NUMBER , PPT.WEIGHT AS WEIGHT , PPT.CARGO_HANDLING_OPERATOR AS CARGO_HANDLING_OPERATOR , PPT.SHIPMENT_PACKING_TYPE AS SHIPMENT_PACKING_TYPE , PPT.SHIPMENT_FLOW_TYPE AS SHIPMENT_FLOW_TYPE , PPT.SHIPMENT_BUILD_TYPE AS SHIPMENT_BUILD_TYPE , PPT.SHIPMENT_CARGO_TYPE AS SHIPMENT_CARGO_TYPE , PPT.REVENUE_TYPE AS REVENUE_TYPE , PFT.JV_FLIGHT_CARRIER_CODE AS JV_FLIGHT_CARRIER_CODE , PPT.PORT_TONNAGE_UID AS PORT_TONNAGE_UID , PPT.AWB_UID AS AWB_UID , PIS.INVOICE_SEPARATION_UID AS INVOICE_SEPARATION_UID , PFT.FLIGHT_TONNAGE_UID AS FLIGHT_TONNAGE_UID FROM PN_FLT_TONNAGES PFT , FZ_AIRLINES FA , PN_TONNAGE_FLT_PORTS PTFP , PN_PORT_TONNAGES PPT , FF_AIRCRAFT_SERVICE_TYPES FAST , SR_PN_INVOICE_SEPARATIONS PIS --new , SR_PN_INVOICE_SEP_DETAILS PISD--new , SR_PN_INV_SEP_PORT_TONNAGES PISPT --new WHERE PFT.FLIGHT_OPERATION_DATE >= trunc( CASE :rundate WHEN TO_DATE('01/01/1900', 'DD/MM/YYYY') THEN ADD_MONTHS(SYSDATE,-1) ELSE ADD_MONTHS(:rundate,-1) END, 'MON') AND PFT.FLIGHT_OPERATION_DATE < trunc( CASE :rundate WHEN TO_DATE('01/01/1900', 'DD/MM/YYYY') THEN TRUNC(SYSDATE) ELSE TRUNC(:rundate) END, 'MON') AND PFT.TYPE IN ('C', 'F') AND PFT.RECORD_TYPE = 'M' AND (PFT.TERMINAL_OPERATOR NOT IN ('X', 'A') OR (PFT.TERMINAL_OPERATOR <> 'X' AND FA.CARRIER_CODE IN (SELECT * FROM SPECIAL_HANDLING_AIRLINE) AND PPT.REVENUE_TYPE IN (SELECT * FROM SPECIAL_REVENUE_TYPE) AND PPT.SHIPMENT_FLOW_TYPE IN (SELECT * FROM SPECIAL_SHIPMENT_FLOW_TYPE) AND PFT.FLIGHT_OPERATION_DATE >= (select EFF_DATE from SPECIAL_HANDLING_EFF_DATE) )) AND PFT.DELETING_DATETIME IS NULL AND FA.AIRLINE_UID = PFT.AIRLINE_UID AND FA.DELETING_DATETIME IS NULL AND PTFP.FLIGHT_TONNAGE_UID = PFT.FLIGHT_TONNAGE_UID AND PTFP.RECORD_TYPE = 'M' AND PTFP.DELETING_DATETIME IS NULL AND PPT.TONNAGE_FLIGHT_PORT_UID (+)= PTFP.TONNAGE_FLIGHT_PORT_UID AND PPT.RECORD_TYPE (+)= 'M' AND PPT.DISCREPANCY_TYPE (+)= 'NONE' AND PPT.ADJUSTMENT_INC_FLAG (+)= 'Y' AND PPT.DELETING_DATETIME (+) IS NULL AND FAST.AIRCRAFT_SERVICE_TYPE_UID = PFT.AIRCRAFT_SERVICE_TYPE_UID AND FAST.DELETING_DATETIME IS NULL AND PIS.TEMPORAL_NAME = TO_CHAR((CASE :rundate --new WHEN TO_DATE('01/01/1900', 'DD/MM/YYYY') THEN TRUNC(SYSDATE) ELSE TRUNC(:rundate) END ), 'YYYYMM') || '00' AND PIS.INVOICE_SEPARATION_UID = PISD.INVOICE_SEPARATION_UID --new AND PISD.INVOICE_SEP_DETAIL_UID = PISPT.INVOICE_SEP_DETAIL_UID --new AND PISPT.PORT_TONNAGE_UID = PPT.PORT_TONNAGE_UID --new AND PIS.PRINT_SUPPORTING_DOC = 'Y';上面是oracle的写法,请转成spark SQL的写法。

2023-06-02 上传