Optical Polarization and Dispersion Precise polarization control, measurement, and analysis

• Comprehensive polarization stabilization/control
• Fast switching capability
• Enables single-sweep spectral PDL measurements with photonic application software suite
• 1240 nm to 1650 nm operating wavelength range
• Robust, no moving optical part

The Keysight Technologies N7786C contains a high-speed lithium niobate based polarization controller and a polarization analyzer that monitors the output signal and provides feedback to the controller. This unit can operate in several modes:

• As a polarization stabilizer, it provides a stable output state of polarization (SOP) even with fluctuations and drifts of the input SOP. The stabilized output signal is guided in a standard single-mode fiber (SMF). The output SOP can be defined in the following ways:
  - When the set-and-forget switch in the user interface is activated, the current SOP is stored and maintained, even if polarization changes occur on the instrument input.
  - Defined Stokes: the target output SOP can be defined by the user using the Stokes parameters, which are then set using the polarization analyzer feedback,
  - Defined sequence: the device switches the SOP of the output signal in a chosen pattern with a cycling speed of up to 100 kSOPs/s.
• As an SOP switch, the N7786C cycles through a sequence of SOPs at a chosen rate up to more than 40 kHz. The internal settings for the SOP sequence are first determined with the stabilizer function for rapid direct switching. SOP switching occurs within a few microseconds. An electrical trigger input can be used to synchronize the scrambler with external events.
• As a traditional scrambler, the N7786C varies the output SOP in a random way. Full coverage of the Poincaré Sphere can be achieved within a few milliseconds.
• As a polarization analyzer, the instrument provides truly high-speed capabilities: Up to 1 M samples can be taken with a sample rate of up to 1 M samples per second.
• As fast-switching polarization controller for single-sweep wavelength dependent PDL measurements in combination with the photonics application software suite (PAS). See the PAS literature for details: www.keysight.com/find/n7700

Many applications of the N7786C are supported by the built-in user interface. Programming uses a new SCPI command set and the instrument is addressed as a VISA resource.
The instrument comes in a compact form factor of just one rack unit height, with LAN and USB interfaces.