{"id":6387,"date":"2026-05-25T02:40:50","date_gmt":"2026-05-25T09:40:50","guid":{"rendered":"https:\/\/www.tfngj.com\/?p=6387"},"modified":"2026-05-25T02:40:51","modified_gmt":"2026-05-25T09:40:51","slug":"ocid-technology-optical-interference-and-vibration-signal-demodulation","status":"publish","type":"post","link":"https:\/\/www.tfngj.com\/pt\/ocid-technology-optical-interference-and-vibration-signal-demodulation\/","title":{"rendered":"OCID Technology: Optical Interference and Vibration Signal Demodulation"},"content":{"rendered":"

In core scenarios such as optical cable operation and maintenance, resource inventory, cable splicing, and emergency repair for communication operators, the OCID testers have become the mainstream solution to replace traditional damaging detection methods including bending, freezing, and cutting. OCID<\/a> (Optical Coherence Identification) technology relies on high-precision optical interference and digital vibration signal demodulation to achieve non-destructive, long-distance, and high-reliability optical cable identification on a single fiber. It provides strong support for communication operators to reduce costs, improve efficiency, and ensure stable service transmission in optical networks.<\/p>\n\n\n

1. Principles of OCID Technology: Optical Interference and Phase Demodulation<\/strong><\/h2>\n\n\n\n

1.1 Optical Interference: The Sensing Core of Vibration Detection<\/strong><\/p>\n\n\n\n

OCID technology adopts a hybrid architecture combining Mach\u2013Zehnder interference and Sagnac interference. The internal laser emits stable coherent light, which is divided into two beams by a 2\u00d72 coupler and transmitted in the fiber to form a closed interference loop. When the cable is tapped or disturbed by external force, the fiber core produces micro-strain and transient refractive index changes, resulting in a stable phase difference between the two optical signals.<\/p>\n\n\n\n

The phase difference can be expressed as: \u0394\u03c6 = 4\u03c0n\u0394L\/\u03bb + 4\u03c0L\u0394n\/\u03bb In the formula, \u03bb represents the operating wavelength (usually 1550 nm), n is the refractive index of the fiber core, L is the fiber length, \u0394L is the strain deformation, and \u0394n is the change of refractive index.<\/p>\n\n\n\n

O OCID testers<\/a> capture the intensity change of interference light and converts weak mechanical vibration into measurable electrical signals. It supports single-ended testing without loopback at the remote end, and can accurately identify broken fibers, APC connectors, UPC connectors and other complex end conditions.<\/p>\n\n\n\n

1.2 Vibration Signal Demodulation: From Waveform to Accurate Identification<\/strong><\/strong><\/p>\n\n\n\n

Demodulation is the key link of OCID technology. After photoelectric conversion by PD detector, the interference signal is processed by PGC (Phase Generated Carrier) and quadrature demodulation algorithm to filter out noise and extract effective features such as vibration amplitude, frequency and time sequence.<\/p>\n\n\n\n

High-performance OCID tester\u00a0equipment provides two intuitive output modes:<\/p>\n\n\n