Optically integrated InP-Si₃N₄ hybrid laser

Abstract

We describe the first demonstration and characterization of an optically integrated InP-Si 3 N 4 hybrid laser. The laser is formed by integration of an InP-based reflective semiconductor optical amplifier with a Si 3 N 4 based feedback waveguide circuit. The circuit comprises a frequency selective and tunable Vernier mirror composed of two microring resonators with slightly different radii. A wide tuning range of more than 43 nm is achieved via the thermo-optic effect. The typical side mode suppression ratio is 35 dB. The narrowest linewidth achieved is about 90 kHz, and the relative intensity noise is less than −135 dBc/Hz.

Photo-induced second-order nonlinearity in stoichiometric silicon nitride waveguides

“…The latter is achieved with extremely thick waveguide cores, fabricated with a novel approach of stepwise filling of pre-etched grooves [13]. This platform has also reached a considerable degree of maturity, allowing two-dimensional tapering [14] for low-loss fiber coupling or realizing hybrid lasers [15,16]. The platform supports also a wide range of optical functionalities [11,17] by offering various different core cross sections for waveguide dispersion engineering, and offers a highly reproducible material dispersion [13,14].…”

Programmable optical processor chips: toward photonic RF filters with DSP-level flexibility and MHz-band selectivity

“…One example of such hybrid integration is an integrated photonic beamformer using a modulator array in InP and a true-time-delay beamforming network in TriPleX [97] as shown in Figure 20. Also shown in Figure 20, Fan et al [32] recently demonstrated a narrow-linewidth laser which is based on a micro-assembly of a gain medium in InP and an external highly selective, low-loss filter in TriPleX. In this work, a key packaging challenge of chipto-chip coupling loss is addressed, which is critical for the performance of the laser.…”

“…More importantly, this system configuration is in favor of full system integration in one unit via the TriPleX-InP hybrid integration. While this particular reconfigurable RF filter has not been demonstrated in such a hybrid integration on the full scale, other parallel works have successfully demonstrated a unit based on the integration of a similar silicon nitride processor chip and an InP chip that provides active components [32]. These works will be discussed further in Section 5.…”

“…A great challenge here is the integration with light sources due to the difficulty of lasing directly in silicon. However, recent advances in hybrid integration of InP and silicon have shown remarkable results tackling this issue [32]. The InP platform features the capability of providing a full range of high-performance active functions including lasers, amplifiers, modulators, and photodetectors [20].…”

“…Although showing a great range of functions, implementing RF signal processing in microwave photonics may require a complex optical system that comprises a combination of many of these functions. In a broad sense, integrating such systems on monolithic chips [28,29] or by means of micro-assembly of multiple chips [30][31][32][33] is a key for the proliferation of their large-scale application in real-world systems. To that scope, we need to simultaneously address the issues of device size, power consumption, and performance stability, as compared with all-electronics solutions [34].…”