The VDL-004 from Luna Innovations is a Miniature Variable Optical Delay Line (ODL) that operates at wavelengths of 840, 1060, 1310, or 1550 nm ± 50 nm (polarization mode) and 840 ± 50 nm, 1060 ± 50 nm, 1260 nm to 1650 nm (single-mode). It has an optical delay range of 0 ps - 130 ps, optical delay resolution of 3.34 ps, and a zero point delay offset of 230 ps. This fiber-coupled ODL has a return loss of 55 dB and an insertion loss of less than 0.8 dB with insertion loss variation of up to 0.4 dB. It has an extinction ratio of over 20 dB for polarization mode and a polarization-dependent loss of 0.1 dB for single-mode fiber. This ODL has a delay repeatability of less than 20 μm and an optical damage power threshold of 300 mW.

The VDL-004 offers continuous control with high precision, zero backlashes, and good thermal stability. It features an optional internal mirror that can cause the light to double pass the device, doubling the delay range, and a locking mechanism for locking the delay at a permanent position. This ODL has convenient mounting brackets that allow mounting in any orientation, as well as easy integration of multiple units on a base plate to form an array. It can be easily integrated into larger instruments or assemblies for precision optical path length control or timing alignment.

The VDL-004 is available in a compact module that measures 78 (L) mm x 22 (W) mm x 15 (H) mm with HI780 or PM Panda (for 840 nm), HI1060 or PM Panda (for 1060 nm), and SMF-28 or PM Panda (for 1310 nm & 1550 nm) fibers and FC/PC, FC/APC, SC/PC, & SC/APC fiber connectors. It is ideal for microwave photonics, phased array antennas, coherent detection systems, optical time division multiplexing (OTDM), optical coherence tomography (OCT), optical interferometry, optical Fourier spectrum analysis, fiber sensors, and OEM applications.