The Nonlinear Lab is dedicated to the characterization of nonlinear optical processes and their application in integrated devices. In particular, the most investigated devices are optical waveguides in silicon. A butt-coupling setup is present, used to inject/extract the light in/from the chip. A high power pulsed pump laser at 1550 nm is available in order to trigger the nonlinearities in the sample. A monochromator with single-photon sensitivity is present, able to characterize the spectrum of the light generated in the nonlinear process. In the lab is also available an up-conversion system for the detection of mid infrared light down to the single photon level.

The measurements performed in the lab can characterize both the classical and quantum properties of the nonlinear processes. In particular, applications like wavelength conversion and single photon generation are standard experiments carried out in the laboratory. The main nonlinear effect studied is the intermodal four wave mixing in silicon-on-insulator waveguides. Particular focus has been recently devoted to the characterization of single photon sources, therefore the laboratory is equipped with single photon detectors, timing electronics (correlators, start/stop time to digital converters) and all the optical components required for quantum effects measurements.

Instrumentation:

• ONEFIVE KATANA HP HIGH POWER PICOSECOND LASER:
  pulsed laser, 40 ps pulse width, 1 – 100 MHz repetition rate, 1550 nm central wavelength
• Id210 SINGLE PHOTON DETECTOR:
  InGaAs SPAD, up to 100 MHz gating frequency, up to 25% detection efficiency
• Excelitas Si-SPADs (visible range)
• Two up-converter devices for the conversion of the mid infrared light to visible photons
• Several tunable CW lasers (1475-1575 nm, 1510-1610 nm, 1260-1650nm), ASE C band source (1530-1565nm), Erbium-doped fiber amplifier (EDFA) 5W (1535-1565nm)
• OSA (600 – 1700 nm)