A novel method to calibrate LiNbO3-based polarization controllers

BENEDETTO S., DJUPSJOBACKA A., HUI R. Q. +3 more

Chang‐Qing Xu, Hideaki Okayama, T. Kamijoh

Xueying Ren, Meinan Guo, Xuyang Wang +8 more

Dynamic polarization controllers are key devices with broad applications in many fields. However, most on-chip polarization controllers still rely on traditional blind-search methods, whereas analytical optical-computing approaches remain insufficiently explored, particularly with respect to calibration and endless polarization control. With the accurate relative phase of Mach-Zehnder interferometer (MZI) being fully controllable on an integrated photonics chip, we present an analytical polarization control (APC) method using four phase shifters and optical computing, eliminating the need for the traditional inefficient blind-search procedure. The basic structures and operations of APC are clarified. The proposed calibration method and endless control method enable continuous APC while compensating for phase differences within the MZI structures. We simulate the influence of the endless control unit on polarization control and quantify the effect of the fourth phase difference on the output extinction ratio. With the fourth phase shifter, the phase difference encountered during Stokes vector measurement can be effectively compensated, and rotations around all three axes on the Poincaré sphere can be realized. These results establish a practical APC architecture based on optical computing for photonics chips. The proposed APC methods, combined with a FPGA-based hardware acceleration, will enable high speed on-chip polarization controllers.

Mieno, Watanabe †↑, Shinada +2 more

Kai Li

The principle,the method and the experimental system of mid-infrared radiance calibration based on parametric amplification technique were introduced.The equation between different polarization source and its photons per mode was deduced.A high power CW laser stabilized at 532 nm was used to pump a LiNbO_3 nonlinear crystal,producing two correlated-photons whose wavelengths were 632.8 nm and 3.34μm,respectively.The under-calibrated blackbody at 3.34μm was injected along the direction of the infrared down-converted photons.With the high relativity of the VIS-IR photon pairs,through the measurement of the visible down-converted photons at 632.8 nm,the radiance of the blackbody source at 3.34μm can be calibrated and 1.53%relative standard uncertainty was reported.

Tetsuya Kawanishi, Takahide Sakamoto, Akito Chiba +1 more