Lasing in a Hybrid Rare‐Earth Silicon Microdisk

Abstract

Silicon photonics is an ideal platform for low-cost, energy-efficient, and high-performance optical microsystems. However, because silicon is an inefficient light emitting material, the development of simple, inexpensive, and scalable monolithic amplifiers and light sources has been a significant challenge. Here, optical gain and lasing in an ultra-compact hybrid rare-earth silicon microdisk resonator are reported. The microdisk design is straightforward and compatible with the fabrication steps and device dimensions available in all silicon photonics foundries, while the thulium-doped tellurite gain medium is added in a low-temperature single-step sputter deposition. This approach allows for low-cost and high-volume wafer-scale manufacturing and co-integration of rare-earth amplifiers and light sources with silicon passive and active devices with no adjustment to standard process flows. The hybrid laser is pumped at standard telecom wavelengths around 1.6 µm and exhibits stable single-mode emission at 1.9 µm, with an internal slope efficiency of 60% and >1 mW on-chip output power. The laser is highly promising for emerging communications and sensing applications and opens new possibilities for the development of monolithic rare-earth optical amplifiers and lasers directly on silicon.

Advances in lithium niobate thin-film lasers and amplifiers: a review

“…For example, REI-doped TeO2 and REI-doped Al2O3 materials were widely used in active integrated photonics for their high rare-earth solubility, large emission cross section, as well as wafer-level deposition techniques 99 , 100 . One consideration in this design is that sufficient overlap between the pattern of the LN layer and the gain material is required to obtain large gains or power output, for example, by depositing the gain material into the microtrenches design to improve the gain performance of the device 101 , 102 . In addition, by introducing the design of REI-doped loaded waveguide, the fabrication process of active devices based on LNOI can be simplified.…”

“…99,100 One consideration in this design is that sufficient overlap between the pattern of the LN layer and the gain material is required to obtain large gains or power output, for example, by depositing the gain material into the microtrenches design to improve the gain performance of the device. 101,102 In addition, by introducing the design of REI-doped loaded waveguide, the fabrication process of active devices based on LNOI can be simplified. For example, silicon nitride materials featuring low transmission loss, refractive index close to LN, and CMOS compatibility are successfully applied on the LNOI platform.…”

Subwavelength Grating Metamaterial Waveguides and Ring Resonators on a Silicon Nitride Platform

“…We quantify the optical intensity overlap with the upper cladding, which we consider the active region, by calculating the electric field energy density factor ( γ A ) using the equation γ A = ∫ A ε | E | 2 dA / ∫ ∞ ε | E | 2 dA , where the integration domain extends over the 2D transverse cross‐sectional area of the waveguide. [ 31,32 ] The overlap is maximized when n SWG and w wg are reduced but a trade‐off is observed between the overlap factor and increasing substrate leakage loss penalty as the mode effective index ( n eff ) decreases and the mode expands deeper into the BOX layer, as shown in Figure 2c. The bend losses also increase significantly for low n eff .…”

Broadband high-Q multimode silicon concentric racetrack resonators for widely tunable Raman lasers

“…SRS is mediated by a coherent phonon population and does not require phase matching between the pump and Stokes waves. Raman lasers are therefore useful to produce output wavelengths at longer wavelengths than available from the pump laser 7 – 23 . Carefully engineering the resonators to have high Q factors over a broad wavelength range is necessary if the Raman lasers were to have a wide tuning range at every resonant wavelength 24 .…”