1550‐nm Band Soliton Microcombs in Ytterbium‐Doped Lithium‐Niobate Microrings

Abstract

Micro‐optical frequency combs are miniaturized coherent light sources exhibiting a tremendous influence on precision spectroscopy, optical clocks, and high‐speed optical communications. The rare‐earth‐doped lithium niobate (LN) is a promising platform to integrate the lasers and comb sources on the same chip of single material. However, microcombs generated in rare‐earth‐doped LN thin film (LNTF) have not yet been fully explored. To explore the protocols of generating optical combs in ytterbium‐doped LNTF, the comb‐like laser is studied in the 1060 nm band, and the dissipative Kerr soliton is experimentally demonstrated in the telecom band in a Z‐cut wafer. The over‐coupled fundamental transverse electric mode with anomalous dispersion is excited at an on‐chip pump power of 75.7 mW to generate the robust bright soliton. The broadband spectrum of the Kerr soliton ranges from 1480 to 1660 nm with 110 comb lines, whose repetition rate is 197.8 GHz. The mode‐locking of the soliton can be achieved as a result of the photorefractive effect of ytterbium‐doped LNTF instead of complex feedback schemes. Numerical simulations are highly accordant with the experimental results. This work expands the microcomb‐generating platform and increases the potential for integrated on‐chip applications including precision ranging and frequency division.

Scalable parallel ultrafast optical random bit generation based on a single chaotic microcomb

“…It should be pointed that there is also no limit on the materials for MRRs. The other materials such as silicon nitride (SiN) 32 , silicon dioxide (SiO 2 ) 33 and lithium niobate (LiNbO 3 ) 34 should be also feasible for chaotic micro-combs. The main reason why we chose the HIDSG MRR in our experiment is its reliable packaging: this kind of MRR can be easily coupling using a fiber array with a low coupling loss.…”

Electro-Optical Comb Envelope Engineering Based on Mode Crossing

“…The lithium niobate has a large transparency window (400 nm–5 μm), strong second-order nonlinearity ( d 33 = 34 pm/V), the ability of periodic poling, and a high-speed optical switch through the EO effect [ 19 ]. Many high-performance optical devices based on TFLN have been demonstrated, such as low-pump wavelength convertors [ 20 , 21 , 22 ], tunable frequency combs [ 23 , 24 , 25 ], and EO modulators with a high frequency and low driving voltage [ 26 , 27 ].…”

Erbium-ytterbium co-doped lithium niobate single-mode microdisk laser with an ultralow threshold of 1 µW

“…An intense desire for high-performance photonic integrated devices such as electro-optic modulators [1][2][3] , optical frequency conversion [4][5][6][7][8][9][10][11] , quantum light sources [12][13][14][15] , optical frequency combs [16][17][18][19][20][21][22] , and ultrafast pulse generation [23] , rapidly motivates the photonic integration platforms to lithium-niobateon-insulator (LNOI) wafer [24][25][26][27] , owing to the outstanding material properties of lithium niobate, such as a broad transparency window (350 nm to 5 μm), a large linear electro-optic, second-order nonlinear, acoustic-optic, and piezo-electric coefficients [24][25][26][27][28] . All the above-mentioned applications have been successfully demonstrated on passive LNOI wafers with unparalleled performance due to the accessible highly confined photonic structures with ultralow loss due to the rapid developments in ion-slicing technique and LNOI nanofabrication technology.…”