High‐Performance Electro‐Optic Modulator on Silicon Nitride Platform with Heterogeneous Integration of Lithium Niobate

Abstract

Silicon nitride (SiN) emerges as an important platform for ultralow loss photonic integrations with complementary metal‐oxide‐semiconductor compatibility. However, active devices, such as modulators, are difficult to realize on pure SiN due to the lack of any electro‐optic (EO) properties of the material. Here, an SiN and lithium niobate (LN) heterogenous integration platform supporting high‐performance EO modulators on SiN waveguide circuits is introduced. An efficient evanescent coupling structure is realized for low‐loss light transitions between the SiN waveguide and the LN ridge waveguide with a measured mode transition loss of only 0.4 dB. Based on this heterogeneous platform, an EO Mach–Zender interference modulator on SiN is built with unprecedented loss, efficiency, and bandwidth performances. A half‐wave voltage of 4.3 V with a modulation bandwidth of 37 GHz and an overall insertion loss of 1 dB is measured for a 7‐mm long device. Data transmission up to 128 Gb s−1 with a bit‐error‐rate of <2.4 × 10‐4 is also demonstrated.

Perspectives of thin-film lithium niobate and electro-optic polymers for high-performance electro-optic modulation

“…Based on this, a 7 mm long hybrid SiN/LN MZM with a bandwidth of 37 GHz and V p of 4.3 V was demonstrated. 75 Generally, compared to the EO modulator based on bulk LN, TFLN modulators show significant improvement in footprint, V p and bandwidth. The length of the commercial packaged LN modulator is about 10 cm, while this length can be significantly reduced to less than 3 cm.…”

“…Based on this, a 7 mm long hybrid SiN/LN MZM with a bandwidth of 37 GHz and V π of 4.3 V was demonstrated. 75…”

Compact and Efficient Thin‐Film Lithium Niobate Modulators

“…Table 1 and 2 summarize the progress of different TFLN modulators with the MZI structure. [ 5,6,12,15,26–107 ] Figure summarizes the half‐wave voltage, device length, and bandwidth of etched and non‐etched TFLN modulators. Both these two kinds of modulators can realize a very high bandwidth.…”

Design of MZI electro-optic modulator on lithium niobate heterogeneous integration platforms

“…The precise processing of lithium niobate materials still poses challenges, which limits the further development of lithium niobate electro-optic modulators. There are some demonstrations that use hybrid optical modes formed by bonding LN to planarized silicon photonic waveguide circuits [3,[10][11][12][13][14] . These devices achieve 3-dB bandwidth greater than 100 GHz at 1550 nm, and a typical VπL product of 2~3 V•cm [1] .…”

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Applying various functional materials to silicon to enhance the functionality of silicon photonics is a potential solution for silicon photonics platform under the requirement of CMOS compatibility [1][2][3] . In this paper, two LN heterogeneous integration platforms have been proposed.

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