Tunable single-mode laser on thin film lithium niobate

Abstract

The erbium-doped lithium niobate on insulator (LNOI) laser plays an important role in the complete photonic integrated circuits (PICs). Here, we demonstrate an integrated tunable whispering gallery single-mode laser (WGSML) by making use of a coupled microdisk and microring on LNOI. A 974 nm single-mode pump light can have an excellent resonance in the designed microdisk, which is beneficial to the whispering gallery mode (WGM) laser generation. The WGSML at 1560.40 nm with a maximum 31.4 dB side mode suppression ratio (SMSR) has been achieved. By regulating the temperature, the output power of the WGSML increases, and the central wavelength can be changed from 1560.30 to 1560.40 nm. Furthermore, 1560.60 and 1565.00 nm WGSMLs have been achieved by changing the coupling gap width between the microdisk and microring. We can also use the electro-optic effect of LNOI to obtain more accurate adjustable WGSMLs in further research.

Integrated Photonics Based on Rare‐Earth Ion‐Doped Thin‐Film Lithium Niobate

“…[138] This phenomenon indicates that the pump light mainly resonates in the in-coupling microdisk, avoiding lasing emission with other longitudinal modes excited by pump light resonating in the out-coupling microdisk. Similar experimental results suggested by the excited green up-conversion fluorescence can be found in the coupled microrings proposed by Zhang et al and the coupled microdisk/ring structures proposed by Liu et al [133,135] B. With a view to achieving single-frequency/mode laser with high output power, one of the two coupled micro-resonators can be well designed to have a relatively long cavity length for stronger light-matter interaction.…”

“…Up to now, C-band single-frequency/mode lasing based on Er:LNOI on-chip coupled dual-cavity design has been successively demonstrated by Gao et al (with a minimum linewidth of 348.139 kHz), [138] Zhang et al (with a side-mode suppression ratio (SMSR) of 26.3 dB, see Figure 9c), [133] Xiao et al (with a minimum linewidth of 1.2 MHz and an SMSR of 31 dB, see Figure 9d), [134] and Liu et al (with an SMSR of 31.4 dB, see Figure 9e). [135] The basic information of these fabricated coupled micro-resonators can be found in Table 2. In addition, we summarize some key features of these single-frequency/mode lasers in the following:…”

Dynamic Bandwidth Allocation for C-Band Shared FBG Sensing and Telecommunications

“…Therefore, it will be impossible to operate TS of impacted wavelengths in affected TChs. Suitable short-pulse narrowband tunable lasers for FBG sensing or TS applications were described by [26], [27], [28], [29], [30]. Using values from Table I we can find that a wavelength is occupied by the laser sweeping for a duration of Tsp laser ≈ 3.766 ms. Each TCh is affected by nλ TCh  10 laser wavelengths, see Fig.…”

Fabrication of the high-Q Si3N4 microresonators for soliton microcombs

“…For soliton comb generation, the pump laser needs to be scanned across the resonance mode from the blue side to the red side. However, because of the existence of the thermal effect [38,51,52] , once the laser is scanned to the red side, the resonance frequency will experience a blue shift, making the soliton state unstable, as shown in Fig. 6(a).…”