Brian Stern's research while affiliated with Columbia University and other places

... By individually controlling the phase of light of wavelength λ, emitted from a sufficiently high number (10 2 < N ch < 10 4 ) of closely spaced (d < λ) emitters, a low divergence (<1 mRad) beam may be scanned at high frequencies (>1 MHz) over a wide (>90°) field of view (FOV) without the emergence of higher order beams and thus maintaining a high (>90%) power fraction in the main output beam 6 . Numerous proof-of-concept demonstrations based on silicon and/or siliconnitride photonics technology have been presented over the last decade, in general using wire-bonded chips with several tens or hundreds of electrical/ optical channels [7][8][9][10] . More recently, the application of more advanced electronic integration techniques shows a pathway to a low unit-cost device consisting of a one dimensional emitter array with N ch > 1000 and d < λ, allowing beam properties compatible with demanding applications such as automotive LIDAR [11][12][13] . ...

... The large mechanical steering solution is less desired because it is susceptible to vibration, temperature, acceleration, and inertial forces, and hence declines in performance. Moreover, they need a time-consuming construction and calibration process, resulting in a high unit price [9][10][11]. Furthermore, arbitrary pointing and quick steering, both of which are required for sophisticated communication and sensor applications, become difficult, if not impossible, to accomplish [12,13]. ...

... The on-chip optical-interconnect approach emerges as an attractive solution, having the advantages of large bandwidth and low power consumption. Silicon photonics (SiPh) is regarded as a promising technology to significantly enhance the transmission capacity [6][7][8][9][10][11][12]. High performance SiPh devices can be fabricated and manufactured by using complementary metal-oxide-semiconductor (CMOS) fabrication technologies at high yield and low cost. ...

... In this process, The survey of Si3N4 waveguide loss evolution over the years. The blue shaded elliptical area indicates prior work using EBL [4,7,10,12,[46][47][48][49][50][51][52][53][54][55], while the red shaded elliptical area highlights those using DUV lithography [9,[56][57][58][59]. The dashed red circle indicates the propagation loss of our device, the lowest recorded for the nonlinear Si3N4 waveguide, achieved with DUV stepper lithography and subtractive processing. ...

... In this regard, 1-D beam steering has been demonstrated with 1-D OPAs that can tightly assemble long and narrow radiators [26][27][28]. These systems are capable of steering the beam in one direction only, unless utilized with a highly precise tunable laser, making 2-D beam steering possible [29]. Furthermore, 2-D beam steering has also been shown by dispersive OPAs [30], circular OPAs [31], and planar OPAs [32]. ...

... Over the past few years, the global demand for bandwidth and capacity has increased exponentially (Ahmad et al. 2021). This rapid increase in data traffic is typically caused by the proliferation of various bandwidth-intensive applications, such as search engines, online combs are reported based on FWM in an optical parametric oscillator with silicon nitride ring resonator (Jacob et al. 2010), an integrated semiconductor laser (Stern et al. 2018), Kerr effect in micro-resonator (Xue et al. 2017) and lithium niobate on insulator modulators (Xu et al. 2022). ...

... Furthermore, a void-free encapsulation is critical in order to guarantee a reduced scattering at the coupling region, minimizing systematic excess losses due to the inter-mode interactions, and increasing the threshold power of failure events. This is of the utmost importance, especially in the perspective of the co-integration of III-V-based reflective semiconductor amplifiers (RSOAs) or even free-running multimode laser sources butt-coupled to ultra-high Q Kerr microresonators for compact, chip-based and power-efficient optical frequency comb sources [31][32][33][34][35][36]. ...

... Recently, integrated OPAs have garnered significant research interest [26][27][28][29][30][31][32][33][34][35][36][37][38][39]. Many researchers have demonstrated integrated OPAs on various platforms, such as silicon-on-insulator (SOI) [28, 29, 31, 33-35, 37, 39], silicon nitride ( Si 3 N 4 ) [26,27,31], and indium phosphide (InP) [40,41]. ...

... Nevertheless, achieving a large FSR necessitates adopting a small bend radius, potentially leading to increased bend losses and decreased Q factors. Consequently, these factors exert a detrimental influence on attributes such as laser linewidth [31] and the efficiency of nonlinear optical processes [32]. ...

... Modulators are indispensable in constructing an on-chip communication system. There are many on-chip modulation methods to implement optical signal processing such as electro-optic modulations 1, 2, 3 , thermo-optic modulations 4,5,6,7,8 and electro-absorption modulations 9 . Especially, thermo-optic modulations with advantages of easy fabrication, low cost and compactness have been applied in many optical devices 10,11,12,13 . ...