User Guide

Remote Control User Guide for the MX / MBX / TLX1 / TLX2 Series Chapter 2: Supported Commands
Rev. E, May 5, 2022 Page 15
2.6. Variable Optical Attenuator (VOA) Commands
The VOA commands described in this section apply to all MX / MBX / TLX1 / TLX2 instrument Item #s. These
commands are provided for controlling the VOA and determining its status are described in the following tables.
Command Syntax Description
Set the Optical
Attenuation Value
VOA:ATTen: N N is a floating point value between 1.0 and 20.0, inclusive,
with units of dB. This command sets optical attenuation of
the VOA and returns 1 on receipt of command. If set while
operating in constant power mode, the operation of the
VOA will not be affected. Instead, the value will be cached
and applied when constant attenuation mode is activated.
Get the Optical
Attenuation Value
VOA:ATTen? Returns the attenuation setting of the VOA as a floating
point value between 1.0 and 20.0, inclusive, with units of
dB.
Get Difference
between Actual and
Setpoint Attenuation
VOA:ERRor? Returns the difference between the attenuation provided by
the VOA and the attenuation setpoint value as a floating
point value with units of dB.
Get Measured
Attenuation Provided
by VOA
VOA:MEASured? Returns the value of attenuation provided by the VOA as a
floating point value with units of dB. The value of
attenuation is the calculated ratio of the optical power
measured before and after the VOA.
Set VOA Mode to
Constant Optical
Output
VOA:MODE: 1 Sets the VOA mode to constant optical output power and
returns 1 on receipt of command. While operating in this
mode, the optical power measured after the VOA is
monitored and the VOA bias voltage is adjusted to maintain
the requested optical output power. Holding the optical
output power constant requires adequate optical power
input.
Set VOA Mode to
Constant Attenuation
VOA:MODE: 0 Sets the VOA mode to constant optical attenuation and
returns 1 on receipt of command. While operating in this
mode, optical power levels measured before and after the
VOA are monitored. The VOA bias voltage is adjusted to
maintain the specified ratio between the two.
Get VOA Mode VOA:MODE? Returns 0 if the VOA mode is set to constant optical
attenuation and 1 if the VOA mode is set to constant optical
output power.
Set the Optical
Output Power Value
in dBm
VOA:OUTput:DBM: N N is interpreted as a floating point value between -20.0 and
20.0, inclusive, and the units are dBm. This command sets
optical output power of the VOA and returns 1 on receipt of
command. While this range exceeds the maximum power
output of the built-in laser, the entire range is supported to
accommodate the use of higher-power external laser
sources. If this value is set while operating in constant
attenuation mode, it will not affect the operation of the
VOA. In this case, the value will be cached and applied
when constant power mode is activated.
Get the Optical
Output Power Value
in dBm
VOA:OUTput:DBM? Returns the power setting of the VOA as floating point
value between -20.0 and 20.0, inclusive, with units of dBm.