Xi'an Institute of Optoelectronics has made progress in the research of integrated light sources for applications such as sensors

[China Instrument Network Instrument Development] As the core of modern optics, especially integrated optics, high-quality pulsed and coherent laser light sources have always been an important focus of academic and industrial circles. Under the support of the "Big Scale Photonic Integrated Chip" of the Chinese Academy of Sciences' Class B Strategic Pilot Science and Technology Project, the micro-nano optics and photonics integration team of the Xi'an Institute of Optics and Fine Mechanics, Chinese Academy of Sciences has recently made a series of research progresses on integrating on-chip light sources.

Ultra-high frequency pulsed laser source generation mechanism

First, a multi-frequency (1-15) stable laser pulse source with a fundamental frequency of 49 GHz was implemented on-chip, and the results of this study were published on July 19th in the journal ACS Photonics. By designing different laser parameters and utilizing the interaction of the optical field gain, nonlinearity and dispersion in the laser cavity, various types of pulsed laser sources have been produced in academic and commercial fields. However, ultra-high-speed optical clocks, high-speed optical communication technologies, microwave photonics, spectrometry, and astronomical optical combs have placed higher demands on the repetitive frequency of laser pulse sources. The on-chip micro-ring resonant cavity developed by Xi'an Opto-Electronics Institute based on the dissipative four-wave mixing effect achieves a stable laser pulse output with a fundamental frequency of 49 GHz, which is effectively reduced compared to ultra-short cavity pulsed lasers by Schawlow and Townes limit the high phase noise. At the same time, the on-chip laser mode selection mechanism was used to realize the multi-rate laser pulses from 49 to 735 GHz, which broke the limitation of the repetition frequency in the free spectral range of the laser cavity.

Secondly, an important breakthrough was made in the mode-locked laser technology on the Fourier transform limit super-narrow spectral sheet. Traditional mode-locking techniques are often used to achieve ultra-short pulses. Researchers have used the mode-locking technique more to broaden the spectral bandwidth to achieve ultra-short, sub-picosecond or even sub-second laser pulses, while the Fourier transform limit Ultra-narrow spectral nanosecond pulsed mode-locked lasers are difficult to implement. Because of their narrow spectral bandwidth, these lasers can be widely used in spectroscopy, sensors, coherent optical communications, and quantum optics. The Xi'an Institute of Optics and Light Engines cooperated with a number of foreign companies to implement an ultra-narrow spectrum integrated passive mode-locked laser with a non-linear amplification loop reflector, in which the core loop reflector uses a unique low loss high refractive index difference. Q-valued microring resonators. The full-length full-width at half maximum (FWHM) of the laser pulse output by the laser is 4.31 ns, the average output power is about 2.5 mW, the peak power can reach about 60 mW, the output amplitude is RMS<2.3%, and the spectrum width is 104.9 MHz, which is lower than the conventional one. Orders of magnitude. The research was published in 2017 in Nature Photonics.

Ultra-narrow spectral mode-locked laser experimental device

The above research results are a series of breakthroughs made by the micro-nano optics and photonics integration team of Xi'an Optics and Opticals following the achievement of cross polarized photon pair generation, on-chip multiphoton entanglement generation, realization of visible optical frequency combs, and high-dimensional optical quantum chips. The development of light quantum integrated chips laid an important foundation.

(Original title: Xi'an Institute of Optoelectronics has made progress in integrated optical chip research)