ИСТИНА

Femtosecond laser writing (FLW) technology is the unrivalled tool for rapid prototyping of integrated photonic devices in various dielectric materials due to its low cost and simplicity. FLW has found a wide range of applications in astrophotonics, optical communications, topological photonics, optofluidics and quantum photonics. Here we report on our latest developments in writing photonic integrated circuits for linear optical quantum computing. Using waveguides at 800 nm based on type-II modification in silica glass, we have fabricated a universal two-qubit processor and a programmable 8-port interferometer with an overall insertion loss of 7-10 dB [1,2]. Thermo-optic phase shifters were created on the top surface by patterning resistive micro-heaters on top of the waveguides in a deposited metal layer by laser ablation performed in the same fabrication setup. Using multiscan waveguides at 920 nm based on a type-I modification in silica glass, we have fabricated a low-loss programmable two-qubit entangled states generator and a 25-port interferometer for boson sampling experiments with an overall insertion loss of 2-3 dB [3,4]. Some of these interferometers were packaged in 19-inch cases with a built-in temperature stabilizer and power sources. Moreover, by varying the size of the waveguide, we created different structures for different tasks in a wide range of wavelengths from 400 to 1550 nm. In addition, depressed cladding waveguides and directional couplers have been fabricated inside crystals doped with rare earth ions [5]. These waveguides can be used as the basis for integrated optical quantum storage based on photon echo.