The OD1-28 Optical Attenuation Meter is designed for signal attenuation in the optical range and is used for optical signal regulation in optical channels, for testing and verification of optical measurement instrumentation in optical wavelength range.


The Attenuation Meter principle of operation is based on optical signal power regulation by introducing seven 2, 3, 4, 8, 16, 30, 32 dB absorptive neutral density filters and 0–3 dB circular variable filter. The absorptive neutral density filters are inserted into optical channel by electromagnetic drives and circular variable filter is controlled with an electrical motor with a reducer. To provide full coverage of the optical channel the electromagnetic drive with a shutter is mounted.

The Optical Attenuation Meter comprises the Mainframe and three Built-in Units with a corresponding wavelength range.

The Mainframe houses power supply and control Units.

The Built-in Unit comprises Optical Unit with a filter drive and a Control device.

The Optical Unit represents a fiber optic section with a line discontinuity. At input and output of line discontinuity lens matching elements are mounted.

The Instrument Control Unit comprises four devices: display and control device, interface bus display device, interface bus communication device. The Instrument is controlled by the front panel buttons (display and control device). The Optical Attenuation Meter operating modes, measured values or the parameters set are displayed on graphical vacuum luminescent indicator. The Control Unit (Microcontroller) controls various Optical Attenuator components, processes and corrects measurement results and supports various communication protocols with a PC (GPIB and RS 232).

Standard “FC-PC” fiber optic connectors are mounted at the Optical Attenuation Meter input.


Operating wavelength range: 0.85±0.05, 1.31±0.05,

1.55 +0.15 mm

Attenuation range: 0–90 dB (the additional fixed attenuation 3±0.5 dB may be introduced)

Attenuator absolute permissible setting error: ±0.2+0.013∙А dB, where A – nominal value of the insertion attenuation (dB)

Initial (insertion) attenuator loss are not more than 3 dB


Operating temperature range: 10–35 °С

Relative humidity at 30 °С: up to 90%

Power: 220±22 V, 50±1 Hz

Power consumption: not more than 40 VA

Dimensions: 368x392x130 mm

Weight: 15 kg