Experimental demonstration of TE/TM polarization-independent frequency upconversion assisted by polarization coupling

Abstract

Optical frequency conversion based on the second-order nonlinearity (χ 2 ) only occurs in anisotropic media (or at interfaces) and thus is intrinsically polarization-dependent. But for practical applications, polarization-insensitive or independent operation is highly sought after. Here, by leveraging polarization coupling and second-order nonlinearity, we experimentally demonstrate a paradigm of TE/TM polarization-independent frequency upconversion, i.e., sum frequency generation, in the periodically poled lithium niobate-on-insulator ridge waveguide. The cascading of quasi-phase-matched polarization coupling and nonlinear frequency conversion is exploited. With a proper transverse electric field, TE and TM mode fundamental waves can be frequency-upconverted with an equal efficiency in the frequency converter. The proposed method may find ready application in all-optical wavelength conversion and upconversion detection technologies.

Microwave Photonic Frequency Multiplier with Low Phase Noise Based on an Optoelectronic Oscillator

“…Thus far, various photonic approaches for frequency multiplication have been proposed and demonstrated [9,10], such as optical heterodyne techniques [11,12], external modulation [13][14][15], the use of optical nonlinear effects of stimulated Brillouin scattering (SBS) [16,17], and so on. In [18], low-noise repetition-rate multiplication is obtained via harmonic injection locking and gain-saturated amplification.…”