Laser interferometry boasts high sensitivity, a wide measurement range, and robustness in harsh environments. Light waves directly define the meter and are easily traceable. Chotest independently developed PLR3000 series fiber optic laser ruler, based on laser interferometry, is a cutting-edge position detection device renowned for its high precision, sensitivity, and speed. In non-contact precision measurement, it offers unparalleled advantages over traditional steel tape measures or glass gratings, featuring more accurate pitch and higher resolution. Its thermal isolation design ensures superior stability, while its quick installation and easy alignment make it user-friendly. The PLR3000 series finds wide applications in modern ultra-precision manufacturing, such as microelectronics, micromechanics, and micro-optics, as well as in lithography and aerospace.

Components of a fiber optic laser ruler
A fiber optic laser ruler typically consists of a laser source, an interferometric measurement probe, and a retroreflector. The laser source emits a coherent light beam, which is divided and recombined by the interferometer to create an interference pattern. The retroreflector reflects the light back to the interferometer, allowing for precise displacement measurement.

1.Laser emission device:

The laser emission device features a built-in helium-neon laser source with exceptional frequency stability, achieving a precision of 0.05ppm (or 0.02ppm). The laser beam is delivered to the interferometric measurement probe via armored fiber, ensuring thermal isolation. The device includes a sophisticated signal processing unit that provides real-time RS422 digital quadrature signals and analog quadrature signals with customizable resolution. Furthermore, a USB software development kit (SDK) is available for secondary development.

2.Interferometer probe:

2.1 Differential Interferometer (DI) Probe Our DI probe offers unmatched precision by employing a differential interferometry technique. The probe splits a laser beam into two paths, one reflecting off a fixed mirror and the other off a moving surface. This configuration quadruples the sensitivity, enabling nanometer-level resolution and minimizing nonlinear errors. It's perfect for applications requiring precise measurement of relative motion, especially in the presence of thermal fluctuations and vibrations.

2.2 Plane Mirror Interferometer (PI) Probe Our PI probe offers superior performance for XY stage motion control and measurement. The probe's unique dual-beam interferometer design and plane mirror configuration provide unmatched resolution and accuracy. The dual-axis option and adjustable output angle make it highly adaptable to various applications.

2.3 Retroreflector Interferometer (RI) Probe Our RI probe offers a versatile and accurate solution for linear measurement applications. With easy installation and a measurement range up to 40 meters, it is perfect for positioning and calibrating equipment. The probe's retroreflector design ensures high reliability and accuracy.

Key Features of Fiber Optic Laser Rulers

Fiber optic laser rulers offer a high level of precision and versatility for linear measurement applications. Here are some of their key technical features:

• High Measurement Accuracy: Linear measurement accuracy can reach up to 0.5ppm.
• High Laser Frequency Stability: Laser frequency stability is as high as 0.05ppm (0.02ppm is optional).
• High Resolution: Native resolution can be as high as 10nm, and can be configured to even higher resolutions through further subdivision.
• High-Speed Measurement: Maximum measurement speed can exceed 2000mm/s.
• Long Measurement Range: Measurement range can reach 4m or more, with customizable options up to 40m.
• Easy Installation and Alignment: Compact size, flexible installation, and significant reduction in Abbe error. The interferometer probe is equipped with an angle adjustment device for easy beam alignment.
• Thermal Isolation of Measurement Optical Path: The laser emission device and the measurement probe are separated, eliminating the impact of host heat dissipation on the measurement path.
• Multi-Channel Output: Up to three probes can be connected simultaneously, enabling multi-axis simultaneous measurement and multi-degree-of-freedom measurement.
• Diverse Output Interfaces: The host output interface includes USB and position output interfaces. Position output interfaces include differential TTL (RS-422/EIA-422), sine and cosine signals (SinCos1Vpp), and USB-SDK.

Application Verification of PLR3000 Series Fiber Optic Laser Ruler

The PLR3000 series fiber optic laser ruler has undergone precision verification in numerous customer applications. By employing a differential interferometer (DI) probe for closed-loop control of a high-precision nanometer positioning stage, nanometer-level position control accuracy has been achieved at any point within a 10mm travel range.