INTUN Tunable Laser
12372-D02, 12/15/2007
Page 21
www.thorlabs.com
The Digital Control Signals
Name
Short Description
_WAVELENGTH_TUNING_ENABLE
When enabled, the INTUN TL-T is ready to accept and respond
to wavelength tuning input
_COHERENCE_CONTROL_ENABLE
When enabled, a dither signal is added to the wavelength control
signal to minimize the influence of standing waves.
_OPTICAL_POWER_ENABLE
When enabled, optical power is emitted from the output fiber.
_CONSTANT_CURRENT_ENABLE
When enabled, the unit is operated in constant current mode.
_FINE_TUNING_ENABLE
When enabled, the cavity temperature can be adjusted to fine
tune the wavelength.
Figure 14: Digital Input Circuitry
Digital Control: _WAVELENGTH_TUNING_ENABLE
When the digital control signal _WAVELENGTH_TUNING_ENABLE is set to LOW (0 V), the unit is
ready to accept and respond to wavelength tuning (using the analog control WAVELENGTH_TUNING
control discussed on page 24).
When the _WAVELENGTH_TUNING_ENABLE signal is set to HIGH (5 V), the wavelength
CANNOT be tuned (changed), and it is set to the middle of its range (i.e., the wavelength that
corresponds to 0 V on the control analog WAVELENGTH_TUNING) regardless of the analog
WAVELENGTH_TUNING control voltage (see page 24).
Digital Control: _COHERENCE_CONTROL_ENABLE
When the digital control signal _COHERENCE_CONTROL_ENABLE is set to LOW (0 V), the
effective optical linewidth of the outputted light is broadened.
Digital Control: _OPTICAL_POWER_ENABLE
When the digital control signal _OPTICAL_POWER_ENABLE is set to LOW (0 V), the output optical
power from the unit is set according to the voltage of the analog optical power input.
When the digital control signal _OPTICAL_POWER_ENABLE is set to HIGH (5 V), the laser diode
inside the INTUN TL-T unit is turned off regardless of the analog optical power input voltage.