Compact MZI modulators on thin film Z-cut lithium niobate

Abstract

In this paper, we designed, implemented, and characterized compact Mach-Zehnder interferometer-based electro-optic modulators. The modulator utilizes spiral-shaped optical waveguides on Z-cut lithium niobate and the preeminent electro-optic effect which is applied using top and bottom electrodes. Optical waveguides are made of rib etched lithium niobate waveguides with bottom silicon oxide cladding, while SU8 polymer covers the top and sides of the rib waveguides. The proposed implementation resulted in low optical losses < 1.3 dB/cm. Moreover, we achieved compact modulators that fit 0.286 cm and 2 cm long optical waveguides in 110 µm × 110 µm and 300 µm × 300 µm areas, respectively. For single arm modulation, the modulators achieved a VπL of 7.4 V.cm and 6.4 V.cm and 3-dB bandwidths of 9.3 GHz and 2.05 GHz, respectively. Push-pull modulation is expected to cut these VπL in half. The proposed configuration avoids traveling wave modulation complexities and represents a key development towards miniature and highly integrated photonic circuits.

Chip-Based Brillouin Processing for Microwave Photonic Phased Array Antennas

“…For example, the lowest V π RF of an E-O modulator is 2.12 V at 50 GHz [165] and has a length of 2 cm, which can be challenging to integrate at each element of a PAA where space is highly constrained. However, folded [183]- [185], or spiral [186] E-O modulators have smaller maximum linear dimension when compared to their straight counterparts, and are attractive solutions for space constrained applications, such as at every element of a PAA. Similarly, acousto-optic non-reciprocal devices have been folded to reduce their onchip footprint, as demonstrated by Kittlaus et al [155].…”

Compact and Efficient Thin‐Film Lithium Niobate Modulators

“…In such a device, the electrodes are above and below the waveguide to accommodate the crystal orientation. [ 13 ] Such a configuration makes the electrical field direction perpendicular to the optical transmission direction. Therefore, the optical waveguide can be bent in any direction without considering the electric field direction as X / Y ‐cut LN.…”

“…Figure 9c shows an example of a compact MZI modulator with spiral arms demonstrated in Z ‐cut LN. [ 13 ] By bending the waveguide, its overall device size is greatly reduced compared with a typical X / Y ‐cut LN‐based modulator. In a total footprint of 110 by 110 μm 2 area, the authors achieved a modulator that fits a 0.286 cm long optical waveguide and a of about 7.4 V · cm.…”

“…a–c) Adapted with permission under the terms of the Optica Open Access Publishing Agreement. [ 13 ] Copyright 2022, Optica Publishing Group. d,e) Adapted with permission.…”

Design and Investigation of Three-Dimensional Polarization-Independent Polymer Mach-Zehnder Interferometers at 1550 Nm

“…For the application of complicated wiring, Mach-Zehnder Interferometer exhibits much interest by meeting several features such as switching (Krishnamurthy et al, 2014), multiplexing/demultiplexing (Ahmmed et al, 2021), sensors (El Shamy et al, 2019), and modulators (Hassanien et al, 2022), etc. in the optical communication system.…”