50GHz gallium arsenide electro-optic modulators for spaceborne telecommunications

Abstract

Travelling-wave electro-optic modulators designed for V-band space applications using gallium arsenide guided-wave technology are presented. The designs feature a low-loss folded optical configuration giving straight-line RF access at one end of the chip, with all optical I/O via the opposite end. This configuration enables the close-packed monolithic modulator arrays needed for phased-array applications, contributes to high modulation bandwidths with low ripple by eliminating directional change in the RF feed arrangements and facilitates compact packaging. While only 1550nm designs are reported here, the AlGaAs material system is versatile, permitting modulators to be realized for a wide range of optical wavelengths, with particular advantage in drive-power at shorter wavelengths. Both single MZ and monolithic dualparallel (IQ) modulators have been assessed up to 70GHz; bandwidths around 50GHz are achieved with low-frequency V of 4.6V. Typically, the folded devices are half the length of conventional format modulators and can accommodate 4 device arrays in the same width package.

Telecommunication Gallium: The Future and Metal of Data Transmission

“…The AlGaAs material system is versatile, permitting designs to be realized for a wide range of optical wavelengths. We have presented basic design data to demonstrate the potential for significant advantage in terms of drive-power at shorter wavelengths 25 . Gallium is a semiconductor, which means it can be used to create faster and more efficient data transmission.…”

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].…”

Expanding the Quantum Photonic Toolbox in AlGaAsOI

“…As a QPIC platform, AlGaAsOI is attractive for its large χ (2) and χ (3) nonlinear coefficients, which enable more efficient spontaneous parametric down conversion (SPDC) and spontaneous four wave mixing (SFWM) than silicon, strong modal confinement due to its large refractive index 15 , a thermo-optic coefficient comparable to silicon for efficient tuning [16][17][18] , and electro-optic 19 and piezo-optic 20 effects for cryogenic tuning. Additionally, varying the aluminum content of AlGaAs enables bandgap engineering such that two-photon absorption, a major challenge in silicon QPICs, is minimal at telecommunication wavelengths 21 .…”