Optical Single Loop Control

Principle of Operation

The OSLC is designed to control the operation of a recirculating fiber loop and to provide electrical signals as trigger/gating for measurement equipment operated together with the recirculating fiber loop. A recirculating fiber loop is used to emulate long transmission lines in optical transmission experiments or, in general, to study the influence of multiple transitions through an optical device under test (DUT), emulating a cascade of the DUT.

The electrical signals which control the optical switches (acousto-optic modulators) are generated by a delay generator inside the OSLC. A graphical user interface is provided to define the loop load time, the loop roundtrip time and the number of loop roundtrips. The proper trigger repetition rates and delays are then set automatically by the software.

The electrical control signals (Gating/trigger outputs) to gate or trigger additional equipment (such as bit error-analyzer, real-time or sampling oscilloscopes, optical spectrum analyzer, polarization scrambler) are also generated by the delay generator inside the OSLC and can be controlled via the graphical user interface.


Remote Control via Graphical User Interface

The graphical user interface (GUI) provides remote control access to the OSLC via RS232 serial port. It allows the following actions:

  • Connecting to the OSLC
  • Set the loop state ("loop off", "back-to-back", "startup" or "recirculating")
  • Set the loop parameters (roundtrip time and number of roundtrips)
  • Fine tune the timing of the optical switches within the OSLC (gating window width offset and delay offset)
  • Set the parameters for the gating outputs (on/off state, polarity, width, roundtrip)
  • Set the signal at the clock output
  • Quit the software and closing the GUI window