The General Photonics VDL-001 is a manually controlled variable optical delay line. Multiple versions are available with path length of up to 1200 picoseconds. A low insertion loss and low variation of insertion loss is critical for most applications and the VDL-001 has less than ±1 dB variation even up to 1200 picoseconds. The delay line is packaged in a small aluminum box to prevent dust or noxious vapors from contaminating the optical path.
Delay is shown on the readout on the side (see below).