{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2019:IHAFJTHW4S37Z3RERWPQMLTDJB","short_pith_number":"pith:IHAFJTHW","canonical_record":{"source":{"id":"1907.05948","kind":"arxiv","version":4},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.ins-det","submitted_at":"2019-07-11T11:34:03Z","cross_cats_sorted":["physics.optics","quant-ph"],"title_canon_sha256":"6049430fd3d26881b4e24069915b314189636e7309f87d655fa7ed8a4bd6d11b","abstract_canon_sha256":"fd56a30ed14d266e168b9d2f0989e3bbdb709b63fc6efa520748fe9b9bfc476b"},"schema_version":"1.0"},"canonical_sha256":"41c054ccf6e4b7fcee248d9f062e6348716a1dc476f9368c317777747a223fb3","source":{"kind":"arxiv","id":"1907.05948","version":4},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1907.05948","created_at":"2026-07-05T00:31:53Z"},{"alias_kind":"arxiv_version","alias_value":"1907.05948v4","created_at":"2026-07-05T00:31:53Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1907.05948","created_at":"2026-07-05T00:31:53Z"},{"alias_kind":"pith_short_12","alias_value":"IHAFJTHW4S37","created_at":"2026-07-05T00:31:53Z"},{"alias_kind":"pith_short_16","alias_value":"IHAFJTHW4S37Z3RE","created_at":"2026-07-05T00:31:53Z"},{"alias_kind":"pith_short_8","alias_value":"IHAFJTHW","created_at":"2026-07-05T00:31:53Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2019:IHAFJTHW4S37Z3RERWPQMLTDJB","target":"record","payload":{"canonical_record":{"source":{"id":"1907.05948","kind":"arxiv","version":4},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.ins-det","submitted_at":"2019-07-11T11:34:03Z","cross_cats_sorted":["physics.optics","quant-ph"],"title_canon_sha256":"6049430fd3d26881b4e24069915b314189636e7309f87d655fa7ed8a4bd6d11b","abstract_canon_sha256":"fd56a30ed14d266e168b9d2f0989e3bbdb709b63fc6efa520748fe9b9bfc476b"},"schema_version":"1.0"},"canonical_sha256":"41c054ccf6e4b7fcee248d9f062e6348716a1dc476f9368c317777747a223fb3","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-07-05T00:31:53.165844Z","signature_b64":"dGh89b3CuzeFdrRac0Y62U8YIZhLZJlxu+fcwArxCn1d4lf/tEC+xrjcJcbjQsVxyae4O2ajT0IPqw67js6iDw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"41c054ccf6e4b7fcee248d9f062e6348716a1dc476f9368c317777747a223fb3","last_reissued_at":"2026-07-05T00:31:53.165346Z","signature_status":"signed_v1","first_computed_at":"2026-07-05T00:31:53.165346Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1907.05948","source_version":4,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-07-05T00:31:53Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"YWdoUi7qqMou8bKriJMMfXbnMgYmU9ohY3XWNClkU9ljpyQhlmp2/Kn1tnkxx8QYkzjpG0oVC1JqoQd4c6v0AA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-06T05:10:28.251242Z"},"content_sha256":"1210cf2d653bba4512919af4c716c673da19902629c43346c72543a5e617c0c2","schema_version":"1.0","event_id":"sha256:1210cf2d653bba4512919af4c716c673da19902629c43346c72543a5e617c0c2"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2019:IHAFJTHW4S37Z3RERWPQMLTDJB","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"High Dynamic Range Externally Time-gated Photon Counting Optical Time-domain Reflectometry","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["physics.optics","quant-ph"],"primary_cat":"physics.ins-det","authors_text":"Bin Li, Guangwei Deng, Haizhi Song, Heng Zhou, Kun Qiu, Qiang Zhou, Ruiming Zhang, You Wang, Yun Ling, Yunxiang Wang, Zhonghua Ou","submitted_at":"2019-07-11T11:34:03Z","abstract_excerpt":"Single photon detector (SPD) has a maximum count rate due to its dead time, which results in that the dynamic range of photon counting optical time-domain reflectometry (PC-OTDR) de-creases with the length of monitored fiber. To further improve the dynamic range of PC-OTDR, we propose and demonstrate an externally time-gated scheme. The externally time-gated scheme is realized by using a high-speed optical switch, i.e. a Mach-Zehnder interferometer, to modulate the back-propagation optical signal, and to allow that only a certain segment of the fiber is monitored by the SPD. The feasibility of"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1907.05948","kind":"arxiv","version":4},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/1907.05948/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"},"verdict_id":null},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-07-05T00:31:53Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"GmktJxqMoM2bSJH1C3vr0INZkWOZJJCTfRjkRUJjs0cDoNzhqqPNO13uI39vJkJQoHSurPgXBzhOR4tQJT03Cg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-06T05:10:28.251634Z"},"content_sha256":"17b06599f61fd98f141fdda6bfe166233c80476826169f93549986161505ff86","schema_version":"1.0","event_id":"sha256:17b06599f61fd98f141fdda6bfe166233c80476826169f93549986161505ff86"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/IHAFJTHW4S37Z3RERWPQMLTDJB/bundle.json","state_url":"https://pith.science/pith/IHAFJTHW4S37Z3RERWPQMLTDJB/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/IHAFJTHW4S37Z3RERWPQMLTDJB/bundle.json","status":"primary"}],"public_keys":[{"key_id":"pith-v1-2026-05","algorithm":"ed25519","format":"raw","public_key_b64":"stVStoiQhXFxp4s2pdzPNoqVNBMojDU/fJ2db5S3CbM=","public_key_hex":"b2d552b68890857171a78b36a5dccf368a953413288c353f7c9d9d6f94b709b3","fingerprint_sha256_b32_first128bits":"RVFV5Z2OI2J3ZUO7ERDEBCYNKS","fingerprint_sha256_hex":"8d4b5ee74e4693bcd1df2446408b0d54","rotates_at":null,"url":"https://pith.science/pith-signing-key.json","notes":"Pith uses this Ed25519 key to sign canonical record SHA-256 digests. Verify with: ed25519_verify(public_key, message=canonical_sha256_bytes, signature=base64decode(signature_b64))."}],"merge_version":"pith-open-graph-merge-v1","built_at":"2026-08-06T05:10:28Z","links":{"resolver":"https://pith.science/pith/IHAFJTHW4S37Z3RERWPQMLTDJB","bundle":"https://pith.science/pith/IHAFJTHW4S37Z3RERWPQMLTDJB/bundle.json","state":"https://pith.science/pith/IHAFJTHW4S37Z3RERWPQMLTDJB/state.json","well_known_bundle":"https://pith.science/.well-known/pith/IHAFJTHW4S37Z3RERWPQMLTDJB/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2019:IHAFJTHW4S37Z3RERWPQMLTDJB","merge_version":"pith-open-graph-merge-v1","event_count":2,"valid_event_count":2,"invalid_event_count":0,"equivocation_count":0,"current":{"canonical_record":{"metadata":{"abstract_canon_sha256":"fd56a30ed14d266e168b9d2f0989e3bbdb709b63fc6efa520748fe9b9bfc476b","cross_cats_sorted":["physics.optics","quant-ph"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.ins-det","submitted_at":"2019-07-11T11:34:03Z","title_canon_sha256":"6049430fd3d26881b4e24069915b314189636e7309f87d655fa7ed8a4bd6d11b"},"schema_version":"1.0","source":{"id":"1907.05948","kind":"arxiv","version":4}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1907.05948","created_at":"2026-07-05T00:31:53Z"},{"alias_kind":"arxiv_version","alias_value":"1907.05948v4","created_at":"2026-07-05T00:31:53Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1907.05948","created_at":"2026-07-05T00:31:53Z"},{"alias_kind":"pith_short_12","alias_value":"IHAFJTHW4S37","created_at":"2026-07-05T00:31:53Z"},{"alias_kind":"pith_short_16","alias_value":"IHAFJTHW4S37Z3RE","created_at":"2026-07-05T00:31:53Z"},{"alias_kind":"pith_short_8","alias_value":"IHAFJTHW","created_at":"2026-07-05T00:31:53Z"}],"graph_snapshots":[{"event_id":"sha256:17b06599f61fd98f141fdda6bfe166233c80476826169f93549986161505ff86","target":"graph","created_at":"2026-07-05T00:31:53Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"graph_snapshot":{"author_claims":{"count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","strong_count":0},"builder_version":"pith-number-builder-2026-05-17-v1","claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"integrity":{"available":true,"clean":true,"detectors_run":[],"endpoint":"/pith/1907.05948/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"Single photon detector (SPD) has a maximum count rate due to its dead time, which results in that the dynamic range of photon counting optical time-domain reflectometry (PC-OTDR) de-creases with the length of monitored fiber. To further improve the dynamic range of PC-OTDR, we propose and demonstrate an externally time-gated scheme. The externally time-gated scheme is realized by using a high-speed optical switch, i.e. a Mach-Zehnder interferometer, to modulate the back-propagation optical signal, and to allow that only a certain segment of the fiber is monitored by the SPD. The feasibility of","authors_text":"Bin Li, Guangwei Deng, Haizhi Song, Heng Zhou, Kun Qiu, Qiang Zhou, Ruiming Zhang, You Wang, Yun Ling, Yunxiang Wang, Zhonghua Ou","cross_cats":["physics.optics","quant-ph"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.ins-det","submitted_at":"2019-07-11T11:34:03Z","title":"High Dynamic Range Externally Time-gated Photon Counting Optical Time-domain Reflectometry"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1907.05948","kind":"arxiv","version":4},"verdict":{"created_at":null,"id":null,"model_set":{},"one_line_summary":"","pipeline_version":null,"pith_extraction_headline":"","strongest_claim":"","weakest_assumption":""}},"verdict_id":null}}],"author_attestations":[],"timestamp_anchors":[],"storage_attestations":[],"citation_signatures":[],"replication_records":[],"corrections":[],"mirror_hints":[],"record_created":{"event_id":"sha256:1210cf2d653bba4512919af4c716c673da19902629c43346c72543a5e617c0c2","target":"record","created_at":"2026-07-05T00:31:53Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"attestation_state":"computed","canonical_record":{"metadata":{"abstract_canon_sha256":"fd56a30ed14d266e168b9d2f0989e3bbdb709b63fc6efa520748fe9b9bfc476b","cross_cats_sorted":["physics.optics","quant-ph"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.ins-det","submitted_at":"2019-07-11T11:34:03Z","title_canon_sha256":"6049430fd3d26881b4e24069915b314189636e7309f87d655fa7ed8a4bd6d11b"},"schema_version":"1.0","source":{"id":"1907.05948","kind":"arxiv","version":4}},"canonical_sha256":"41c054ccf6e4b7fcee248d9f062e6348716a1dc476f9368c317777747a223fb3","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"41c054ccf6e4b7fcee248d9f062e6348716a1dc476f9368c317777747a223fb3","first_computed_at":"2026-07-05T00:31:53.165346Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-07-05T00:31:53.165346Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"dGh89b3CuzeFdrRac0Y62U8YIZhLZJlxu+fcwArxCn1d4lf/tEC+xrjcJcbjQsVxyae4O2ajT0IPqw67js6iDw==","signature_status":"signed_v1","signed_at":"2026-07-05T00:31:53.165844Z","signed_message":"canonical_sha256_bytes"},"source_id":"1907.05948","source_kind":"arxiv","source_version":4}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:1210cf2d653bba4512919af4c716c673da19902629c43346c72543a5e617c0c2","sha256:17b06599f61fd98f141fdda6bfe166233c80476826169f93549986161505ff86"],"state_sha256":"eba2b0dfed21bc70492535015b350cc7568d415ce99e8abe37c9ca8494b4d782"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"8QQixDCfYZNv3U28jbz59BNbUSKK380cWhICjVE8+G2/JZjGIUdaRE80rLSAUXXWiu+75oB5wsfWRYrGa1dgBA==","signed_message":"bundle_sha256_bytes","signed_at":"2026-08-06T05:10:28.256052Z","bundle_sha256":"d36aa07497ef4e9f9f4b50bd147d629e55e933449ce38a94fa7716c27c285fdd"}}