Extinction ratio monitoring type polarization rotation system
The extinction ratio monitoring type polarization rotation system addresses ghosting issues by outputting orthogonal polarization states without a polarizer, ensuring accurate optical circuit measurements by determining polarization states based on light intensity ratios.
JP2026099115APending Publication Date: 2026-06-18OPT GATE
Patent Information
- Application Number
- JP2024213256
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-12-06
- Publication Date
- 2026-06-18
AI Technical Summary
Technical Problem
The polarization controller in existing low coherence reflectometers generates ghosts due to the presence of a polarizer, leading to erroneous detection of abnormal locations in the measured optical circuit.
Method used
An extinction ratio monitoring type polarization rotation system that outputs orthogonal polarization states without a polarizer, comprising a polarization controller, a branching unit, a polarizer unit, and a monitor unit, which determines the polarization states based on maximum and minimum light outputs.
Benefits of technology
The system effectively suppresses ghosting, a defect caused by the polarizer, leading to erroneous detection of abnormal locations in the measured optical circuit.
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Smart Images

Figure 2026099115000001_ABST
Abstract
This suppresses the generation of ghosting in the optical path from the polarization controller to the multiplexing optical coupler. [Solution] The extinction ratio monitoring type polarization rotation system 10 is installed in the optical path between a third optical coupler 3 that is incident on the measurement light from the light source and emits reflected light L2 reflected by the optical circuit under test, and a fourth optical coupler 4 that combines the reference light L1 and the reflected light L2. It includes a polarization controller 11 that can change the polarization state of the incident light in various ways and controls the emitted light to a predetermined polarization state, a branching unit 12, a polarizer unit 13, and a monitor unit 14 that monitors the extinction ratio. Based on the output of the monitor unit 14, the set values of the polarization controller 11 that result in the output of the maximum light intensity and the output of the minimum light intensity where the polarization states are orthogonal are stored in the memory unit. After switching these settings, the intensity of each beat signal is measured using a differential amplifier 7, making it possible to detect defective parts of the optical circuit X under test without false detection.
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Citation Information
Patent Citations
Low-coherence reflectometer
JP2002250675A