9沼津工業高等専門学校研究報告
第 52 号，2018 年 1 月㏻ಙᕤᏛࡢࡓࡵࡢග㏿ᐃᐇ㦂బ⸨ ᠇ྐ*Experiments of Light-velocity Measurements for Communication Engineering
Kenji Sato*
Abstract: Experiments of light-velocity measurements have been described for the education ofcommunication engineering. Light velocities in air and via several cables are measured.
Accuracy of three digits is realized through a short propagation distance of 1-2 m by utilizing
high-frequency technologies.
Key Words: light-velocity measurement, communication engineering, high-frequency technology㟁☢Ἴࢆᛂ⏝ࡍࡿ㏻ಙᢏ⾡࡛ࡣ㸪ග㏿ࡣᇶ♏ⓗ࡛㔜せ࡞䠍䠊䛿䛨䜑䛻ࣃ࣓࣮ࣛࢱ࡛࠶ࡿ㸬ᮏሗ࿌࡛ࡣ㸪ᐇ㦂ᐊ࡛⡆౽࡟ග㏿ࢆ

2017 ᖺࡢࣀ࣮࣋ࣝ≀⌮Ꮫ㈹ࡣ㸪㔜ຊἼࡢほ ࡟ࡘ࠸࡚୚࠼ࡽࢀࡓ[1]㸬ࡑࡢᐇ㦂࡛ࡣ㔜ຊἼࡑࡢࡶࡢࢆほᐃࡍࡿ᪉ἲ࡜ᚓࡽࢀࡓ⤖ᯝࢆ㏙࡭ࡿ㸬ࡑࢀࡽ࡟᪂つᛶࡣ࡞ࡋ࡚࠸࠸ࡀ㸪ලయⓗ࡞ᐇ㦂⣔ࡢᵓᡂࡸᡭ㡰ࢆグ㏙ࡋ㸪Ꮫ⏕ᐇ㦂ࢆࡿࢃࡅ࡛ࡣ࡞ࡃ㸪㔜ຊἼࡢ㐍⾜᪉ྥ࡟ᑐࡍࡿග㊰ࡢ┦㐪࡟ᐇ᪋ࡍࡿࡓࡵࡢᮦᩱࢆᥦ౪ࡍࡿ㸬⏝࠸ࡽࢀࡓᐇ㦂⣔ࡣ㸪ྛࡼࡗ࡚ග㏿ࡀኚ໬ࡍࡿࡇ࡜ࢆほ ࡋ࡚࠾ࡾ㸪࣐࢖ࢣࣝࢯࣥ

✀㏻ಙࡢᇶᮏⓗ࡞ᵓᡂ࡜࡞ࡗ࡚࠾ࡾ㸪㏻ಙᕤᏛࡢᏛ⩦࡟࡜̺࣮࣮ࣔࣞࡢᐇ㦂ࡢ෌᮶࡛࠶ࡿ㸬࣐࢖ࢣࣝࢯ̺࣮࣮ࣥࣔࣞࡗ࡚᭷ຠ࡛࠶ࡿ㸬≉࡟㸪࣐࢖ࢡࣟἼ㡿ᇦࢆᢅ࠺㧗࿘Ἴᢏ⾡ࡢᐇ㦂ࡣ㸪ගࢆఏᦙࡍࡿ࢚࣮ࢸࣝࡢᏑᅾࢆド᫂ࡍࡿࡓࡵ࡟ࡢಟᚓ࡟ᐤ୚ࡍࡿ࡜⪃࠼ࡿ㸬⾜ࢃࢀࡓࡀኻᩋ࡟⤊ࢃࡗࡓ[2]㸬࢔࢖ࣥࢩࣗࢱ࢖ࣥࡣ࢚࣮ࢸ➨㸰❶࡟࠾࠸࡚㸪኱Ẽ୰ࡢྍどග࡜࣐࢖ࢡࣟἼࡢఏᦙ㏿ࣝࡢᏑᅾࢆྰᐃࡋ㸪ග㏿ᗘ୙ኚࡢཎ⌮࡟ᇶ࡙ࡃ┦ᑐᛶ⌮ㄽᗘ ᐃ࡟ࡘ࠸࡚㏙࡭ࡿ㸬➨㸱❶࡛ࡣ㸪ྛ✀ࢣ࣮ࣈࣝࡢఏᦙࢆᵓ⠏ࡋࡓ㸬ࡑࡇ࡛㔜ຊἼࡢᏑᅾࡀ⌮ㄽⓗ࡟ᑟฟࡉࢀࡓ㸬㏿ᗘ ᐃ࡟ࡘ࠸࡚㏙࡭ࡿ㸬࣐࢖ࢣࣝࢯ̺࣮࣮ࣥࣔࣞࡢᐇ㦂ࡀ㸪௒ᗘࡣ㔜ຊἼࡢᏑᅾࢆ

Oscilloscopeド᫂ࡍࡿࡓࡵ࡟෌ࡧⓏሙࡋࡓ㸬ࡇࡢ᪉ἲ࡟ࡼࡿ㔜ຊἼࡢ᳨

Oscillator

Bias TEEࡀ㸪⌧௦ࡢ⛉Ꮫᢏ⾡ࡀࡑࢀࢆྍ⬟࡜ࡋࡓࡇ࡜ࡣ㦫Ⴣ࡟್ࡍࡿ㸬ග㏿ᗘ୙ኚࡢཎ⌮ࡸࡑࢀ࡟ᇶ࡙ࡃ┦ᑐᛶ⌮ㄽࡣ㸪≀⌮Ꮫࡢ᰿ᖿࢆ࡞ࡍ㔜せ࡞ࢸ࣮࣐࡛࠶ࡿ㸬┿✵୰ࡢග㏿ࡣ㸪c =47 :Divider

2.99792458 x 108 m/s ࡜ᐃ⩏ࡉࢀ࡚࠾ࡾ㸪㛗ࡉࡢᇶ‽ࢆ୚㻰㻯

ฟ࡟ࡣ 21 ࢣࢱ௨ୖ࡜࠸࠺㸪ᴟࡵ࡚㧗࠸⢭ᗘࢆせồࡉࢀࡓ㻰㻯LD࠼ࡿ࡞࡝≀⌮㔞ࡢᇶ♏࡟࡞ࡗ࡚࠸ࡿ㸬኱Ẽ୰㸪࠶ࡿ࠸ࡣᏱLensPDᐂ✵㛫࡛ࡢග㏿ࢆ ᐃࡍࡿヨࡳࡣ㸪࢞ࣜࣞ࢜࡟ጞࡲࡿ࡜ࡉ
ࢀ࡚࠸ࡿ[2]㸬ࡑࡢᚋ㸪㛗࠸Ṕྐࢆ⤒࡚࠸ࡃࡘ࠿ࡢ᪉ἲࡀ⪃᱌ࡉࢀ㸪⌧௦࡛ࡣ┿✵୰࡛ࡢ㧗⢭ᗘ࡞ ᐃࡀ࡞ࡉࢀ࡚࠸ࡿ㸬ⴭ⪅ࡣ㸪ᮏᰯ࡛ 2 ᖺ⏕ࡀᒚಟࡍࡿࠕ࣑ࢽ◊✲ࠖ࡟࠾࠸࡚㸪2017 ᖺᗘ㸪ࠕගࢆ ࡿ㸪ࢃ࠿ࡿࠖࢆࢸ࣮࣐࡜ࡋ࡚ᐇ᪋ࡋࡓ㸬≀⌮⌧㇟ࢆ⌮ゎࡍࡿୖ࡛ග㏿ࢆయ㦂ࡍࡿࡇ࡜ࡀ㔜せ࡛࠶ᅗ㸯㸬኱Ẽ୰ࡢྍどගࡢග㏿ࢆ ᐃࡍࡿᐇ㦂⣔㸬䠎䠊኱Ẽ୰䛾ග㏿ ᐃ
㸰㸬㸯 ྍどගࡾ㸪┦ᑐㄽ࡬ࡢᡬࢆ㛤ࡃࡁࡗ࠿ࡅ࡟࡞ࡿ࡜⪃࠼ࡓ㸬ග㏿

ᅗ 1 ࡟㸪኱Ẽ୰࡛ࡢྍどගࡢග㏿ࢆ ᐃࡍࡿᐇ㦂⿦⨨ࡢᐃࡢṔྐࡸᐇ㝿ࢆᏛࡧ㸪ග㏿ ᐃࢆయ㦂ࡋࡓ㸬ࡲࡓ㸪࣮ࣞᵓᡂࢆ♧ࡍ㸬ග※࡟ࡣ㉥Ⰽ༙ᑟయ࣮ࣞࢨ(LD; Laser Diode)ࢨගࢆᛂ⏝ࡋࡓ㊥㞳ィࢆධᡭࡋ㸪ཎ⌮➼ࢆㄪ࡭ࡓ㸬ࡇࡢᤵࢆ⏝࠸࡚࠾ࡾ㸪ཷගჾࡣࢩࣜࢥࣥ࣍ࢺࢲ࢖࣮࢜ࢻ(PD;ᴗࢆ㏻ࡋ࡚㸪ග㏿ࢆ㧗⢭ᗘ࡟ ᐃࡍࡿࡇ࡜ࡣᐜ࡛᫆ࡣ࡞ࡃ㸪Photo-diode)࡛ᵓᡂࡉࢀࡿ㸬࣮ࣞࢨࡢὀධ㟁ὶ࡟㧗࿘Ἴಙ

㏻ಙᢏ⾡ࡸ㧗࿘Ἴᢏ⾡ࡀ㔜せ࡛࠶ࡿࡇ࡜ࢆ෌ㄆ㆑ࡋࡓ㸬ྕࢆ㔜␚ࡋ࡚ኚㄪࡋ㸪✵㛫ࢆఏᦙᚋ㸪ཷගჾ࡛ཷಙࡋ࢜ࢩ* 㟁Ẽ㟁ᏊᕤᏛ⛉ࣟࢫࢥ࣮ࣉ࡛Ἴᙧࢆほ ࡍࡿ㸬ࡇࢀࡣ㸪✵㛫ග㏻ಙࡢᇶᮏ

Department of Electrical and Electronics Engineeringⓗ࡞ᐇ㦂⣔࡛࠶ࡿ㸬ග㏿ࡣ㸪LD ࡜ PD ࡢ㊥㞳ࢆኚ໬ࡉࡏ

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沼津工業高等専門学校研究報告

第 52 号ࡓ᫬ࡢ㐜ᘏࢆ ᐃࡍࡿࡇ࡜࡛ホ౯࡛ࡁࡿ㸬㐜ᘏࡣ㸪LD ࡟ᅗ㸰࡟㸪࢜ࢩࣟࢫࢥ࣮ࣉ࡛ほ ࡉࢀࡓἼᙧࡢ㸯౛ࢆ♧ࡍ㸬㔜␚ࡍࡿಙྕ※࠿ࡽศᒱࡉࢀࡓ㟁Ẽಙྕ(ཧ↷ಙྕ)࡜ගཷ

ᅗ୰ RF ࡣ 300 MHz ṇᘻἼࡢ㟁Ẽಙྕ㸦ཧ↷ಙྕ㸧࡛࠶ಙಙྕ࡜ࢆẚ㍑ࡍࡿࡇ࡜࡛ ᐃࡉࢀࡿ㸬Ꮫ⏕ᐇ㦂࡛౑⏝ࡍࡾ㸪PD ࡣཷಙࡋࡓಙྕἼᙧ࡛࠶ࡿ㸬2.111 ns ࡢ㐜ᘏࡀほࡿᐇ㦂ྎ⛬ᗘࡢᗈࡉ࡛ᐇ᪋࡛ࡁࡿࡼ࠺࡟㸪LD ࡜ PD ࡢ㊥ࡉࢀ࡚࠸ࡿ㸬ࡇࡢ㐜ᘏࡣ┦ᑐⓗ࡞್࡛࠶ࡾ㸪LD ࡜ PD

㞳ࢆ 1 m ⛬ᗘ࡜ࡍࡿࡓࡵ࡟ࡣ㸪㧗㏿࡞ಙྕࡀᚲせ࡟࡞ࡿ㸬㛫ࡢ㊥㞳ࢆቑῶࡍࡿࡇ࡜࡛ኚ໬ࡍࡿ㸬LD ࡸࣞࣥࢬࡢᵓᡂᮏᐇ㦂࡛ࡣ㸪
LD ࡢኚㄪಙྕࢆ 300 MHz ࡢṇᘻἼ࡜ࡋࡓ㸬➼ࢆኚ࠼࡚㸲ᅇ⾜ࡗࡓ ᐃ⤖ᯝࢆ㸪ᅗ㸱࡟♧ࡍ㸬ྛ ᐃ࡛300 MHz ࡢ࿘ᮇࡣ 3.3 ns ࡛࠶ࡾ㸪1 ࿘ᮇ࡛ࡢගࡢఏᦙ㊥LD ࡜ PD 㛫㊥㞳ࢆ㸱Ⅼྲྀࡗ࡚࠾ࡾ㸪ᅗ୰ࡢ┤⥺ࡣᅇᖐ┤㞳ࡣ 1 m ࡜࡞ࡿ㸬LD ࢆ㧗㏿࡛ኚㄪࡍࡿࡓࡵ㸪ࣂ࢖࢔ࢫࢸ⥺࡛࠶ࡿ㸬ࡇࡢ┤⥺ࡢഴࡁ࠿ࡽග㏿ࢆホ౯ࡍࡿ㸬㐜ᘏ᫬㛫࢕࣮(Bias TEE; Anritsu, A3N1001)ࢆ⏝࠸࡚┤ὶ㟁ὶ࡜ࡢ ᐃ࡛ࡣ㸪࢜ࢩࣟࢫࢥ࣮ࣉࡢ᫬㛫ศゎ⬟ 1 ps ࡛⢭ᗘࡀỴ㧗࿘Ἴಙྕࢆ㔜␚ࡋ࡚࠸ࡿ㸬ࡲࡓ㸪LD ࡟ࡣ࢖ࣥࣆ࣮ࢲࣥࡲࡿ㸬LD ࡜ PD 㛫ࡢ㊥㞳ࢆ࣓ࢪ࣮ࣕ࡟ࡼࡾ 1 mm ࡢศゎࢫᩚྜ⏝ࡢ 47 :᢬ᢠࢆ┤ิ࡟᥋⥆ࡋ࡚࠸ࡿ㸬Ᏻ౯࡞ CAN⬟࡛ ᐃࡋ࡚࠸ࡿ㸬⤖ᯝ࡜ࡋ࡚㸪 ᐃࡉࢀࡓග㏿ࡢ᭷ຠᩘᆺ LD (SANYO, DL-3247-165)࡛࠶ࡿࡀ㸪300 MHz ௨ୖᏐࡣ㸱ࢣࢱ࡛࠶ࡿ㸬⾲㸯࡟㸪ᚓࡽࢀࡓ⤖ᯝࢆ♧ࡍ㸬㸲ᅇࡢ࡛ࡢኚㄪࡀྍ⬟࡛࠶ࡗࡓ㸬300 MHz ࡢಙྕ※࡜ࡋ࡚㸪ࢩᐃ࡛ࡣ㸪ᖹᆒ 3.02 x 108 m/s ࡢ್ࡀᚓࡽࢀࡓ㸬No. 2 ࡢࣥࢭࢧ࢖ࢨ࣮(HP, 8341A)ࢆ⏝࠸ࡓ㸬ཷಙ࡟ࡣ㸪ᖏᇦ 300ᐃ್ࢆ㝖ࡅࡤ㸪ᖹᆒࡣ 3.00 x 108 m/s ࡜࡞ࡾ㸪᭷ຠᩘᏐMHz ࡢ Si PD (Hamamatsu, S3883)ࢆ⏝࠸ࡓ㸬PD ࡟࠾࠸ෆ࡛ᐃ⩏್࡟୍⮴ࡍࡿ㸬 ᐃ್࡟ࡸࡸࡤࡽࡘࡁࡀࡳࡽࢀࡓ㸬࡚ࡶࣂ࢖࢔ࢫࢸ࢕ࢆ⏝࠸࡚㏫᪉ྥࡢ┤ὶ㟁ᅽࢆ㔜␚ࡋ࡚ࢸ࣮ࣈࣝୖ࡛ PD ࡢ఩⨨ࢆኚ࠼࡚ࣞࣥࢬࢆㄪᩚࡋᐇ㦂ࡋࡓ࠸ࡿ㸬㟁ὶࣔࢽࢱᶵ⬟ࡀ࠶ࡿ㟁※(ADVANTEST, R6240A)

ࡀ㸪ගᏛ࣋ࣥࢳࢆ⏝࠸ࢀࡤ㸯㍈ୖ࡛ࡢ఩⨨ኚ໬࡜࡞ࡾ㸪⢭ࢆ⏝࠸࡚࣍ࢺ㟁ὶ㸦┤ὶᡂศ㸧ࢆ ᐃࡋ࡚࠸ࡿ㸬PD ࡢฟᗘࡸ෌⌧ᛶࢆྥୖ࡛ࡁࡿ㸬ຊࡣ㸪ྠ㍈ࢣ࣮ࣈࣝࢆ௓ࡋ࡚┤᥋࢜ࢩࣟࢫࢥ࣮ࣉ(Agilent,MSO9254A)࡟᥋⥆ࡉࢀࡿ㸬࢜ࢩࣟࢫࢥ࣮ࣉ࡛ࡣධຊ࢖ࣥ
ࣆ࣮ࢲࣥࢫࢆ 50 : ࡟タᐃࡍࡿ㸬PD ࡢཷග㠃ࡣ┤ᚄ 1.5mm ࡜ᑠࡉࡃ㸪ཷಙಙྕࢆቑᖜჾ➼⏝࠸࡞࠸࡛┤᥋ほ ࡍࡿࡓࡵ࡟ࡣ࣮ࣞࢨගࢆ㞟ගࡍࡿᶵᵓࡀ୙ྍḞ࡛࠶ࡿ㸬ᮏᐇ㦂࡛ࡣ CD ࡟⏝࠸ࡽࢀ࡚࠸ࡓࣞࣥࢬࢆᚤືྎୖ࡟タ⨨ࡋ㸪PD ࡟᥋⥆ࡋࡓ┤ὶ㟁※ࡢ㟁ὶࡀ᭱኱࡜࡞ࡿࡼ࠺࡟఩⨨ㄪᩚࡋ࡚࠸ࡿ㸬⾲㸯㸬኱Ẽ୰ࡢග㏿ ᐃ⤖ᯝ㸬No1234ᖹᆒ

ග㏿ (x108 m/s)
2.99
3.06
2.99
3.02
3.02

㸰㸬㸰 ࣐࢖ࢡࣟἼගࡀ㟁☢Ἴ࡛࠶ࡿࡇ࡜ࡣ࣐ࢡࢫ࢙࢘ࣝࡀ᫂ࡽ࠿࡟ࡋࡓࡇ࡜࡛࠶ࡿࡀ㸪㟁☢Ἴࡢఏᦙ㏿ᗘࢆ ᐃࡍࡿࡇ࡜࡛ග㏿࡜୍⮴ࡍࡿࡇ࡜ࢆ☜ㄆࡍࡿ㸬 ᐃཎ⌮ࡣ࣮ࣞࢨගࡢሙྜ࡜ྠᵝ࡛࠶ࡿࡀ㸪ኚㄪ࡞ࡋ࡛ࡼࡾ⡆౽࡞ᵓᡂ࡜࡞ࡿ㸬ᐇ㦂ࡢᵓᡂࢆᅗ㸲࡟♧ࡍ㸬ᅗ㸯࡜ྠࡌ㧗࿘Ἴಙྕ※ࢆ⏝࠸࡚㸪Ἴ㛗ࢆ▷ࡃࡍࡿࡓࡵ㸪࿘Ἴᩘࢆ 2 GHz ࡜ࡋࡓ㸬┤᥋࢔ࣥࢸࢼᅗ㸰㸬㧗࿘Ἴಙྕ(RF)࡜ཷಙಙྕ(PD)Ἴᙧ㸬(Antenna 1) ࡟ ࣐ ࢖ ࢡ ࣟ Ἴ ࢆ ౪ ⤥ ࡋ 㸪 ู ࡢ ࢔ ࣥ ࢸ ࢼ(Antenna 2)࡛ཷಙࡋࡓᚋ㸪࢜ࢩࣟࢫࢥ࣮ࣉ࡛Ἴᙧࢆほࡋ࡚࠸ࡿ㸬ᅗ㸯ࡢග㏿ᐇ㦂࡛ࡣ⩌㏿ᗘࡢ ᐃ࡛࠶ࡿࡀ㸪ᅗ㸲࡛ࡣ఩┦㏿ᗘࡢ ᐃ࡜࡞ࡿ㸬࢔ࣥࢸࢼ࡟ࡣ༞ᴗ◊✲࡛స〇ࡋࡓ㸪ࣈࣛ࢘ࣥ࢔ࣥࢸࢼ࡜ࣃࢵࢳ࢔ࣥࢸࢼ[3]ࢆ⏝࠸ࡓ㸬

Antenna 1

Antenna 2

Oscillator
Dividerᅗ㸱㸬LD㸫PD 㛫㊥㞳࡟ᑐࡍࡿ㐜ᘏ᫬㛫㸬

Oscilloscopeᅗ㸲㸬࣐࢖ࢡࣟἼࡢ఩┦㏿ᗘࢆ ᐃࡍࡿᐇ㦂⣔㸬

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通信工学のための光速測定実験⣔ 1.55 Pm ᖏ࢝ࢵࢺ࢜ࣇࢩࣇࢺࣇ࢓࢖ࣂ࡛࠶ࡾ㸪࣎ࣅࣥ࡟ᕳ࠿ࢀ࡚࠸ࡿ㸬
Function
Generator

Fiber

Oscilloscope

㻰㻯

PIN PDDFB LDᅗ㸳㸬 2 GHz ࡢ࣐࢖ࢡࣟἼࡢほ Ἴᙧ㸬ᅗ㸳࡟㸪ほ ࡉࢀࡓἼᙧࢆ♧ࡍ㸬 ࢔ࣥࢸࢼࢆ௓ࡋ࡚✵㛫ࢆఏᦙࡋࡓἼᙧ࡜ࢣ࣮ࣈࣝࢆ௓ࡋ࡚᥋⥆ࡉࢀࡓཧ↷ಙ

3 dB Couplerᅗ㸵㸬ගࣇ࢓࢖ࣂ୰ࡢග㏿ࢆ ᐃࡍࡿᐇ㦂⣔㸬ྕࡀ࡯ࡰ㔜࡞ࡗࡓ≧ែ࡜࡞ࡿࡼ࠺࡟ㄪᩚࡋ࡚࠸ࡿ㸬ࡑࡢᚋ㸪࢔ࣥࢸࢼ㛫ࡢ㊥㞳ࢆኚ࠼ࡿ࡜✵㛫ఏᦙᚋࡢಙྕࡀ㐜ᘏ࡟ࡼࡾ⛣ືࡍࡿ㸬㸳࿘ᮇ࡜㸯㸮࿘ᮇࡎࢀࡓ఩⨨ࢆ ᐃࡋࡓ⤖ᯝࢆ㸪ᅗ㸴࡟♧ࡍ㸬ᅗ୰ࡢ┤⥺ࡣᅇᖐ┤⥺࡛࠶ࡿ㸬ࡇࡢ⤖ᯝ࠿ࡽ㸪఩┦㏿ᗘࢆホ౯ࡍࡿ࡜㸪3.00 x 108 m/s ࡢ್ࡀᚓࡽࢀ㸪ග㏿࡜୍⮴ࡍࡿࡇ࡜ࡀ☜ㄆࡉࢀࡓ㸬࢔ࣥࢸࢼࡢ኱ࡁ
ࡉࡀἼ㛗ࡢ 1/4 ⛬ᗘ࡛࠶ࡾ㸪ࡑࢀ࡟ẚ࡭࡚༑ศ኱ࡁ࡞㊥㞳ࡀᚲせ࡜࡞ࡿ㸬2 GHz ࡟࠾ࡅࡿἼ㛗ࡣ 15 cm ࡛࠶ࡾ㸪2 m⛬ᗘࡢ㊥㞳ኚ໬࡛ග㏿ࢆ ᐃࡍࡿࡇ࡜ࡀྍ⬟࡜࡞ࡗࡓ㸬ᅗ㸶㸬400 m ࡢගࣇ࢓࢖ࣂఏᦙᚋࡢほ Ἴᙧ㸬
400 m ࡢගࣇ࢓࢖ࣂ࡟ࡘ࠸࡚ほ ࡉࢀࡓἼᙧࢆᅗ㸶࡟

Delay (ps)♧ࡍ㸬㸰ࡘࡢࣃࣝࢫἼࡣ㸪▷࠸⤒㊰ࢆ㏻ࡗࡓࣃࣝࢫ࡜ 400
5000

m ࡢගࣇ࢓࢖ࣂࢆ㏻㐣ࡋࡓࣃࣝࢫ࡛࠶ࡿ㸬㸰ࡘࡢࣃࣝࢫࡢ

4000᣺ᖜࡢ㐪࠸ࡣගࢥࢿࢡࢱࡸࣇ࢓࢖ࣂࡢᦆኻ࡟ࡼࡿ㸬ࡑࢀࡽ

3000

ࡢ᫬㛫ᕪࡼࡾග㏿ࢆホ౯ࡍࡿ㸬100 m ࡢගࣇ࢓࢖ࣂ࡟ࡘ࠸
࡚ࡶྠᵝࡢ ᐃࢆ⾜࠸㸪㸰ࡘࡢ ᐃ࠿ࡽఏᦙ㏿ᗘ࡜ࡋ࡚㸪2000

2.03 x 108 m/s ࡀᚓࡽࢀࡓ㸬1000㸱㸬㸰 ྠ㍈ࢣ࣮ࣈࣝ

040

ྠ㍈ࢣ࣮ࣈ࡛ࣝࡣ㸪᫬㛫㡿ᇦ཯ᑕ⋡ィ
80

120

160

200

Distance (cm)240ᅗ㸴㸬࢔ࣥࢸࢼ㛫㊥㞳࡟ᑐࡍࡿ㐜ᘏ᫬㛫㸬䠏䠊䜿䞊䝤䝹୰䛾ග㏿ ᐃTime-domain Reflectometry)ࡢཎ⌮ࢆ⏝࠸ࡿ㸬ᅗ㸷࡟♧ࡍࡼ࠺࡟㸪ࣃࣝࢫⓎ⏕ჾࡼࡾⓎ⏕ࡉࢀࡓ▴ᙧἼಙྕ(ࣃࣝࢫᖜ50 ns㸪❧ࡕୖࡾ᫬㛫 8 ns)ࢆ T ศᒱࢆ௓ࡋ࡚ྠ㍈ࢣ࣮ࣈࣝ࡟ఏᦙࡍࡿ㸬ࢣ࣮ࣈࣝࡢ⤊➃ࡣ࣮࢜ࣉࣥ࡜ࡍࡿ㸬⤊➃࡛ࡢ཯ᑕἼࢆ T ศᒱࢆ௓ࡋ࡚࢜ࢩࣟࢫࢥ࣮ࣉ࡛ほ ࡍࡿ㸬Oscilloscope㸱㸬㸯 ගࣇ࢓࢖ࣂࢣ࣮ࣈࣝ㏻ಙ࡛⏝࠸ࡿྛ✀ࢣ࣮ࣈࣝෆࡢಙྕఏᦙ㏿ᗘࢆ ᐃࡍࡿ㸬᭱ึ࡟㸪ගࣇ࢓࢖ࣂࢣ࣮ࣈࣝ࡟ࡘ࠸࡚㸪 ᐃ⣔ࢆᅗ㸵

(TDR;FunctionGeneratorCable࡟♧ࡍ㸬ග※࡟ࡣ㸪1.55 Pm ᖏศᕸᖐ㑏ᆺ༙ᑟయ࣮ࣞࢨ(DFB LD)ࣔࢪ࣮ࣗࣝ(NEL, NLK5C5E2LK)ࢆ⏝࠸ࡓ㸬࣮ࣞࢨගࡣ㸪ࣃࣝࢫⓎ⏕ჾ(Agilent, 33500B)ࡢ▴ᙧἼಙྕ(ࣃࣝࢫᖜ 100 ns㸪❧ࡕୖࡾ᫬㛫 8 ns)࡛ኚㄪࡉࢀࡿ㸬ฟᑕ

T Branchᅗ㸷㸬ྠ㍈ࢣ࣮ࣈࣝ୰ࡢఏᦙ㏿ᗘࢆ ᐃࡍࡿᐇ㦂⣔㸬

ගࢆ 3 dB ࢝ࣉࣛ࡟ࡼࡾ 2 ࡘ࡟ศᒱࡋ㸪∦᪉ࡢ⤒㊰࡟㛗ᑻ 50 m ࡢྠ㍈ࢣ࣮ࣈࣝࢆ᥋⥆ࡋࡓ࡜ࡁほ ࡉࢀࡓἼᙧࢆࣇ࢓࢖ࣂࢆ⤖ྜࡍࡿ㸬2 ࡘࡢ⤒㊰ࡢගࡣ 3 dB ࢝ࣉࣛ࡟ࡼᅗ㸯㸮࡟♧ࡍ㸬཯ᑕἼࡢࣃࣝࢫᙧ≧ࡀ␗࡞ࡿࡀ㸪ࢣ࣮ࣈࣝࡾ෌ࡧ⤖ྜࡉࢀ㸪InGaAs PIN PD ࣔࢪ࣮ࣗࣝ(NEC,ࡢᦆኻ࡟ࡼࡿ㸬㸰ࡘࡢࣃࣝࢫࡢ᫬㛫ᕪࡣྠ㍈ࢣ࣮ࣈࣝࢆ NDL547PIC)࡟ࡼࡾ᳨ฟࡉࢀࡿ㸬PD ࡟ࡣ㟁ụ࡜࢟ࣕࣃࢩ

᚟ࡋࡓ᫬㛫࡛࠶ࡿࡇ࡜࠿ࡽఏᦙ㏿ᗘࢆホ౯ࡍࡿ㸬20 m ࡢࢱ࡟ࡼࡿࣂ࢖࢔ࢫᅇ㊰ࢆ᥋⥆ࡋ࡚࠸ࡿ㸬ࣇ࢓࢖ࣂࡣ㸪▼ⱥྠ㍈ࢣ࣮ࣈࣝ࡟ࡘ࠸࡚ࡶྠᵝࡢ ᐃࢆ⾜࠸㸪㸰ࡘࡢ ᐃ࠿

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沼津工業高等専門学校研究報告

ࡽ㸪ఏᦙ㏿ᗘ㸪1.96 x 108 m/s ࡀᚓࡽࢀࡓ㸬第 52 号 ኱Ẽ୰࡟ẚ࡭ࢣ࣮ࣈࣝ୰࡛ࡢග㏿ࡣ⣙ 2/3 ࡜࡞ࡗ࡚࠸ࡿ㸬ࢣ࣮ࣈࣝ୰࡛ࡢග㏿ vp ࡣ㸪࣮ࣔࢻศᩓࢆ↓どࡋᖹ㠃Ἴ࡜ࡳ࡞ࡏࡤḟᘧ࡛୚࠼ࡽࢀࡿ㸬‫ݒ‬௣ ൌଵ

ξఢఓ

(1)

ࡓࡔࡋ㸪Hࡣㄏ㟁⋡㸪Pࡣ㏱☢⋡࡛࠶ࡿ㸬ග㏿ࡣㄏ㟁⋡ࡢᖹ᪉᰿࡟཯ẚ౛ࡍࡿ㸬ẚㄏ㟁⋡ࡢᖹ᪉᰿ࡀᒅᢡ⋡࡛࠶ࡾ㸪ග㏿ࡀᒅᢡ⋡࡟཯ẚ౛ࡍࡿࡇ࡜ࢆព࿡ࡋ࡚࠸ࡿ㸬≉ᛶ࢖ࣥࣆᅗ㸯㸮㸬50 m ࡢྠ㍈ࢣ࣮ࣈ࡛ࣝほ ࡉࢀࡓἼᙧ㸬࣮ࢲࣥࢫ Z0 ࡀ᪤▱ࡢྠ㍈ࢣ࣮ࣈࣝࡸ LAN ࢣ࣮ࣈ࡛ࣝࡣ㸪༢఩㛗ࡉᙜࡓࡾࡢ㟼㟁ᐜ㔞 C ࢆ㸪㸱㸬㸱 LAN ࢣ࣮ࣈࣝ‫ܥ‬ൌ LAN ࢣ࣮ࣈࣝ࡟ࡘ࠸࡚ࡶྠ㍈ࢣ࣮ࣈࣝ࡜ྠᵝࡢ ᐃࢆଵ௩೛ ௓బ(2)⾜࠺㸬࢝ࢸࢦ࣮ࣜ5e ࡢ LAN ࢣ࣮ࣈࣝࢆ⏝࠸ࡓ㸬⿕ ᐃࢣ࠿ࡽぢ✚ࡶࡿࡇ࡜ࡀ࡛ࡁࡿ㸬ྠ㍈ࢣ࣮ࣈࣝࡢ≉ᛶ࢖ࣥࣆ࣮࣮ࣈࣝ௨እࡢ ᐃ⣔ࡣྠ㍈ࢣ࣮ࣈ࡛ࣝᵓᡂࡉࢀ࡚࠸ࡿࡓ

C = 102 pF/m ࡀᚓࡽࢀࡿ㸬ࢲࣥࢫࡀ 50 :࡛࠶ࡿࡇ࡜࠿ࡽ㸪ࡵ㸪LAN ࢣ࣮ࣈࣝ࡜ࡢ᥋⥆࡟ࡣࣂࣛࣥࡀᚲせ࡜࡞ࡿ㸬ᮏࡇࢀࡣ㸪ᕷ㈍ࡉࢀ࡚࠸ࡿྠ㍈ࢣ࣮ࣈࣝࡢ௙ᵝ್ 100 pF/mᐇ㦂࡛ࡣ Ethernet Test Fixture (Agilent, N5392-66404)

࡟࡯ࡰ➼ࡋ࠸㸬LAN ࢣ࣮ࣈ࡛ࣝࡣ㸪Z0 = 100 :࠿ࡽ㸪C =ࢆ⏝࠸ࡓ㸬ࡲࡓ㸪ಙྕ※࡜ࡋ࡚࢜ࢩࣟࢫࢥ࣮ࣉࡢࢸࢫࢺಙ

45.8 pF/m ࡀᚓࡽࢀࡓ㸬ྕ㸦᪉ᙧἼ㸪❧ࡕୖࡾ᫬㛫 0.4 ns㸧ࢆ⏝࠸ࡓ㸬10 m ࡢ LANࢣ࣮ࣈ࡛ࣝほ ࡉࢀࡓἼᙧࢆᅗ㸯㸯࡟♧ࡍ㸬 ᐃࡉࢀࡓ᫬㛫ᕪ࠿ࡽ㸪ఏᦙ㏿ᗘ 2.18 x 108 m/s ࡀᚓࡽࢀࡓ㸬䠑䠊䛚䜟䜚䛻
㏻ಙᢏ⾡࡟ᇶ࡙࠸ࡓග㏿ ᐃᐇ㦂࡟ࡘ࠸࡚㸪ᵓᡂࡸ ᐃἲࡢヲ⣽࡜ᚓࡽࢀࡓ⤖ᯝ࡟ࡘ࠸࡚㏙࡭ࡓ㸬✵㛫ࢆఏᦙࡍࡿྍどග࡜࣐࢖ࢡࣟἼ㸪ཬࡧྛ✀ࢣ࣮ࣈࣝࢆఏᦙࡍࡿಙྕ㏿ᗘࢆホ౯ࡋࡓ㸬✵㛫ఏᦙ࡛ࡣ㸪Ꮫ⏕ᐇ㦂ᐊෆ࡛ᐇ᪋ࡍࡿࡇ
࡜ࢆ᝿ᐃࡋ㸪㧗࿘Ἴᢏ⾡ࢆ⏝࠸࡚ 1-2 m ⛬ᗘࡢ㊥㞳࡛ග㏿ᐃࡀྍ⬟࡛࠶ࡿࡇ࡜ࢆ♧ࡋࡓ㸬ᚓࡽࢀࡓග㏿ࡢ᭷ຠᩘᏐࡣ㸱ࢣࢱ࡛࠶ࡗࡓ㸬ࡇࢀࡽࡢෆᐜࡣ㸪㏻ಙᕤᏛࡢᏛ⩦㸪≉ᅗ㸯㸯㸬10 m ࡢ LAN ࢣ࣮ࣈ࡛ࣝほ ࡉࢀࡓἼᙧ㸬࡟㧗࿘Ἴᢏ⾡ࡢಟᚓ࡟ᙺ❧ࡘࡶࡢ࡜⪃࠼ࡿ㸬ㅰ㎡䠐䠊⪃ᐹ2017 ᖺᗘ㸪ᮏᰯ 2 ᖺࡢඹ㏻⛉┠ࠕ࣑ࢽ◊✲ࠖ࡟ྲྀࡾ⤌␗࡞ࡿಙྕ※࡜ᵓᡂࢆ⏝࠸࡚㸪኱Ẽ୰࡜ࢣ࣮ࣈࣝ୰ࡢග㏿ࢆ ᐃࡋࡓ⤖ᯝࢆ⾲㸰࡟ࡲ࡜ࡵࡿ㸬᭷ຠᩘᏐࡣ㸱ࢣࢱ࡛࠶ࡿ㸬㊥㞳ࡢ ᐃ⢭ᗘࢆ㧗ࡵࡿࡇ࡜࡛㸲ࢣࢱ௨ୖࡢ⢭ᗘࡀࢇࡔᑠ㔝ᑎṌ㍤ྩ㸪㈅ᔱᚿᩯྩ㸪㤶ᕝ㣁ኴྩ࡟ឤㅰࡋࡲࡍ㸬ཧ⪃ᩥ⊩[1] The Royal Swedish Academy of Science, “The Laserྍ⬟࡛࠶ࡿ㸬㸰㸬㸰⠇࡛㏙࡭ࡓ኱Ẽ୰ࡢ࣐࢖ࢡࣟἼࡢᐇ㦂࡛ࡣ㸪఩┦Interferometer Gravitational-wave Observatory and㏿ᗘࡀ ᐃࡉࢀࡓࡀ㸪௚ࡢ ᐃ࡛ᚓࡽࢀࡓ್ࡣ⩌㏿ᗘ࡛࠶

the First Direct Observation of Gravitational Waves,”ࡿ㸬ගࣇ࢓࢖ࣂ࡛ࡣἼ㛗ศᩓ࡟ࡼࡾ఩┦㏿ᗘ࡜⩌㏿ᗘࡣ㸪Kungl. Vetenskaps Akademien㸪Oct. 2017.

1.55 Pm ᖏ࡛ 1 %௨ୖ␗࡞ࡿ㸬ࡲࡓ㸪⩌㏿ᗘศᩓࡀ㛗㊥㞳
ఏ㏦࡟࠾࠸࡚ၥ㢟࡜࡞ࡗ࡚࠸ࡿ㸬⾲㸰㸬 ᐃࡉࢀࡓග㏿ࡢẚ㍑㸬
ఏ㏦㊰✵㛫㸦኱Ẽ㸧ගࣇ࢓࢖ࣂྠ㍈ࢣ࣮ࣈࣝLAN ࢣ࣮ࣈࣝග㏿ (x108 m/s)
3.00
2.03
1.96
2.18

[2] ౛࠼ࡤ௨ୗࡢᩥ⊩ཧ↷㸹㟖⏣ග୍㸪͇Ṕྐࢆኚ࠼ࡓ≀⌮ᐇ㦂㸪͆ ୸ၿ(ᰴ)㸪Jun. 1996.
[3] ෆᒣ┤ဢ㸪͆⎔ቃ㟁Ἴࡢ㟁ຊኚ᥮ᢏ⾡࡟㛵ࡍࡿ◊✲㸪͇ᖹᡂ 24 ᖺᗘ἟ὠᕤᴗ㧗➼ᑓ㛛Ꮫᰯ㟁Ẽ㟁ᏊᕤᏛ⛉༞ᴗㄽᩥ㸪Mar. 2013.