These optical delay lines are high‑performance fiber‑based devices designed to provide precisely controlled time delays for light signals over a wide wavelength range of 400–2000 nm. By combining high quality input and output fiber collimators with a carefully engineered free‑space propagation region, the delay lines enable exceptionally fine control of optical path length and therefore signal timing. The result is low insertion loss and sub‑picosecond resolution, making them ideal for modern high‑speed photonics, test and measurement, and coherent communication systems.

At the core of each delay line is an optical architecture that projects light from an input fiber into free space, controls the distance traveled in air, and efficiently couples the light back into an output fiber. The optical path length is varied either by changing the physical separation between the collimators or by reflecting the beam from a precisely positioned movable reflector. Because the speed of light in free space is well known and the mechanical motion is accurately controlled, the devices provide a direct and repeatable relationship between mechanical displacement and temporal delay, which can be calibrated in picoseconds for straightforward use in timing‑critical experiments and systems.

The delay line family includes several mechanical formats tailored to different integration needs and performance requirements. Lead screw‑based models, such as the ODL‑100 and ODL‑300, deliver stable, linear motion with excellent repeatability, and are available in manual or motorized configurations. For users who prefer direct micrometer adjustment, the ODL‑200 offers intuitive, fine‑resolution control suitable for benchtop experiments and quick optical path optimization. Reflector‑style designs, including manual and servo‑driven versions of the ODL‑600 and ODL‑650, extend the delay range while preserving low loss and robust alignment, supporting ranges from tens of picoseconds up to over 1200 picoseconds.

For applications where space is at a premium, the ODL‑700 miniature delay line provides up to approximately 13 picoseconds of delay in a footprint not much larger than a standard fiber patch connection. This compact design is particularly attractive for OEM integration in instruments such as portable interferometers, compact optical coherence tomography systems, and embedded fiber sensors, where mechanical stability, ease of mounting, and minimal added insertion loss are essential.

These optical delay lines are available with singlemode, multimode, or polarization maintaining (PM) fibers to match a broad variety of system architectures. For polarization‑sensitive applications, PM implementations typically use PANDA‑style fibers, offering excellent polarization extinction and stability. This is especially important for coherent detection, interferometric metrology, and polarization‑encoded communication schemes where any unwanted polarization rotation or fluctuation directly degrades signal quality and measurement accuracy.

The ability to build delay lines from alternative PM fiber structures or customer‑supplied fibers increases flexibility for specialized use cases, such as non‑standard operating wavelengths, custom numerical apertures, or fibers optimized for specific dispersion characteristics. This customizable fiber approach aligns the delay line’s behavior with the rest of the optical system, improving coupling efficiency, polarization alignment, and long‑term reliability in both laboratory and industrial environments.

Users can select between purely manual adjustment and advanced electrically controlled versions depending on their workflow and automation needs. Manual devices rely on precision lead screws or micrometers, delivering smooth mechanical motion and stable delay settings suitable for alignment tasks, static operating points, or occasional reconfiguration. The mechanical assemblies are engineered for low backlash and good thermal stability, ensuring that the set delay remains consistent over time and under typical laboratory conditions.

Electrically controlled delay lines incorporate servo motors with position encoders, enabling closed‑loop motion control with sub‑micron positioning accuracy. This translates into temporal resolution better than 0.003 picoseconds, more than sufficient for characterizing ultrafast pulses, compensating path length fluctuations, or conducting automated scan routines.