Digital Variable Optical Attenuators (DVOAs), SM Fiber Coupled

Features

• PC Controlled and USB Powered
  • Control with GUI Software or Serial Commands
• Two Modes of Operation:
  • Calibrated Attenuation: Set Attenuation in dB Relative to Factory Calibration
  • Manual: Directly Control the Operating Voltage of the Internal VOA
• Dark Mode VOA: Maximum Attenuation When Powered Off
• Single Mode Fiber Pigtail Input and Output with FC/APC Connectors
  • Custom Units with FC/PC, LC/PC, or SC/APC Connectors Available by Contacting Tech Sales
• Compact Size: 108.7 mm x 27.9 mm x 59.7 mm

Thorlabs' DV Series Digital Variable Optical Attenuators (DVOAs) with Single Mode (SM) Fiber Pigtails provide >30 dB optical attenuation from 980 to 1250 nm or >25 dB optical attenuation from 1250 to 1650 nm, with a fast response time of <0.5 ms. They are designed to be fully controlled from either a PC running the DigitalVOA Application GUI (see the Software tab) or using serial commands. Two operating modes are available. Operating the attenuator in "Calibrated Attenuation" mode allows the user to set a specific attenuation change, in dB, by referencing the internal calibration points at specific wavelengths (see the Specs tab for the standard calibration wavelengths for each item). In this mode the user can hit the REF button in the software (see the image to the lower left) to set the 0 dB value of the attenuation scale to the current Attenuation Target value. "Manual" mode allows the user to control the attenuation by directly setting the VOA voltage target, useful for wavelengths far from the calibration points.

Click to Enlarge
This screenshot shows the GUI set to the Calibrated Attenuation mode, in which the user can request a specific attenuation change, in dB, to be applied to the incoming optical signal. The user can set the 0 dB value of the attenuation scale to the current Attenuation Target by pushing the REF button above the left side of the attenuation scale. Before the REF button is pushed, Calibrated Attenuation mode utilizes the internal calibration points at specific wavelengths to set the attenuation scale and the REF button appears black, as shown here. After the 0 dB reference has been set, the REF button turns green.

The optical input and output ports are 0.5 m long SM optical fiber pigtails terminated with 2.0 mm narrow key FC/APC connectors. Custom units with FC/PC, LC/PC, or SC/APC connectors and custom calibration wavelengths are available upon request; please contact Tech Sales for more information.

The attenuators can both be powered and controlled via USB connection to a PC. A USB-ABL-60 USB 2.0 Type-A to Mini-B Cable with Locking Screw is included with each instrument. An RS-232 serial connection can also be used to send commands to the attenuator; however, if power is not provided by a USB connection to a PC, a separate 5 V USB power supply must be used, such as the DS5 Regulated Power Supply.

Dark Mode VOA
When the DVOA is powered off or "disabled", the device operates at "full-dark" or maximum attenuation. As a fail-safe, the DVOA wil only depart from maximum attenuation if it is enabled and a set point is specified.

Software
The DigitalVOA Application is a user-friendly GUI that allows the user to select between the Calibrated Attenuation and Manual modes, set attenuation parameters, and enable or disable the instrument. Please see the Software tab for details and to download the software package. The USB and RS-232 ports can both be used to connect to the GUI software. Additionally, the DVOAs can be operated without the software GUI with SCPI-type serial commands delivered through either the RS-232 or USB port. In order to use the USB interface, the software package must be installed on the connected PC, as the software package also installs a custom Windows^® USB driver. When both the USB and RS-232 ports are connected, commands can be sent to either port and are executed in the order they arrive (to avoid confusion, it is recommended to send commands to only one port).

Mounting
The DVOAs can be post mounted with the ECM100 or ECM225 aluminum clamps.

Note: These attenuators have fiber optic pigtails for ease of use and connector cleaning. The fiber coupling efficiency is highly dependent on connector quality, fiber type, and concentricity. All these parameters, plus the internal loss of the DVOA, contribute to the base insertion loss of the device that will be different for every user application. As a result, the calibrated attenuation is always relative to (or in addition to) the base insertion loss of the device in the user’s setup.

SM Fiber Coupled Digital Variable Optical Attenuator Panels

Click to Enlarge

Click to Enlarge

Software

Version 1.0.1

Click the link below to download the DigitalVOA Application Software.

Software for the DV Series Digital Variable Optical Attenuators

Control with the DigitalVOA Application
The DigitalVOA Application is designed for straightforward use of the DV Series instruments. This software GUI provides full control over the variable optical attenuators, allowing the user to select between the Calibrated Attenuation or Manual modes, set attenuation parameters, and enable or disable the instrument. The software requires a computer running the Windows^® 10 or 11 operating system.

Control via Serial Commands
Serial commands can also be used to control the DVOAs in either the Calibrated Attenuation or Manual modes, set attenuation parameters, receive instrument status, and disable or enable the attenuator. The commands can be sent from a computer running the Windows^® 10 or 11 operating system to the USB or RS-232 port. Descriptions of each command are included in the manual. Note that the software GUI installer also installs the required driver for USB remote control. The installer is not required for remote control over the RS-232 interface.

DVOA Operation Modes

The images below are examples of the DigitalVOA Application software GUI when used to control the DV Series instrument. The Calibrated and Manual modes are summarized below, please see the manual for additional details. When the DVOA is connected via USB, the GUI will detect the individual instrument's information, such as the product name and serial number as shown in the images below. The appropriate GUI is chosen by selecting the COM port associated with the desired DVOA model and serial number upon starting the software. This basic information will not be available when connecting via RS-232 and the DVOA will be identifiable by COM port only.

Click to Enlarge
Calibrated Attenuation Mode: This operation mode allows the user to request a specific attenuation change, in dB, to be applied to the incoming optical signal. This mode utilizes the internal calibration points at specific wavelengths, which can be selected using the "Calibrated Wavelength (nm)" box (e.g., 1310, 1550, or 1590 nm). The user should pick the calibrated wavelength that most closely matches the input wavelength for the best results. The user can hit the REF button above the left side of the attenuation scale to set the current Attenuation Target as the 0 dB refererence attenuation value on the scale, which will be indicated by the REF button turning green

Click to Enlarge
Manual Mode: This operation mode allows the user to directly control the operating voltage of the internal VOA within its operational limits and step it manually using the on-screen buttons. The "Monotonic Limit" function will limit the voltage range so the actual attenuation changes monotonically with voltage. Outside the monotonic range, the user can drive the attenuator to determine the exact minimum or maximum attenuation voltage (which is slightly different for each unit).