- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Mid-infrared dual-comb spectroscopy with room-temperature bi-functional interband cascade lasers and detectors
摘要： Interband cascade (IC) laser structures offer attractive potential for operation at room temperature as both broadband coherent sources of mid-infrared light and fast photodetectors. This makes the realization of extremely compact spectrometers on a monolithic platform possible, and even dual-comb spectroscopy (DCS) configurations. IC comb devices are perfect candidates for this configuration, since they develop near-THz-wide optical frequency comb spectra from a millimeter-sized cavity, using a multi-stage structure that can also function as a very fast photodetector. In this work, we leverage IC photodetectors with a gigahertz bandwidth to demonstrate a self-contained, free-running, room-temperature DCS system in the mid-infrared. The DCS system used detection by the same bi-functional IC device structure to measure 1,1-difluoroethane over (cid:2)600 GHz of optical coverage around 3.6 mm. These results show that the IC platform is suitable for full integration as a broadband, high-resolution on-chip spectrometer in a future chemical sensing system.
关键词： mid-infrared,photodetectors,dual-comb spectroscopy,interband cascade lasers,room-temperature
更新于2025-09-23 15:21:01
-
[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Rate Equation Modeling of Interband Cascade Lasers
摘要： Interband cascade lasers (ICLs) are power-efficient mid-infrared laser sources for applications in sensing of numerous molecules and in free-space optical communications. The static performances of ICLs including the lasing threshold and the output power have been significantly improved since its first demonstration by R. Yang [1]. GaSb-based ICLs have optimal performance in the spectral range of 3-4 μm, which is hard to reach for the quantum cascade laser counterpart [2]. This work proposes a rate equation model for studying dynamical characteristics of ICLs including the intensity modulation (IM) response, the relative intensity noise (RIN), and the frequency noise (FN). Taking into account carrier dynamics in the W-shape active region while ignoring those in the electron and hole injectors [3], the rate equations for the carrier number N, the photon number S, and the phase φ of the electric field read. Based on the standard small-signal analysis of the above rate equations, we obtain analytical formulas for IM response, RIN, and FN, respectively (not shown in this paper). The inset of Fig. 1(a) shows that ICLs exhibit an underdamped resonance peak in the IM response at a low pump current, and the modulation bandwidth increases with increasing pump current as conventional laser diodes. Figure 1(a) proves that more gain stages are desirable for enhancing the modulation bandwidth of ICLs. The inset of Fig. 1(b) shows that the RIN is raised at the resonance frequency, while a small stage number reduces the RIN in the whole spectral range. Figure 1(b) demonstrates that the RIN at the low-frequency range (<1.0 GHz) increases nonlinearly with the gain stage number. The inset of Fig. 1(c) shows that the FN of ICLs is raised at the resonance frequency, while a small stage number reduces the FN in the whole spectral range as well. The intrinsic spectral linewidth of ICLs in Fig. 1(c) is obtained from the low-frequency FN level. It is found that the intrinsic linewidth linearly increases with the gain stage number, which is consistent with the derived analytical formula. In summary, we theoretically prove that a large gain stage number is desirable for enhancing the modulation bandwidth, while a small stage number is favorable to reduce both the RIN and the FN/linewidth of ICLs.
关键词： Interband cascade lasers,rate equation model,frequency noise,intensity modulation,relative intensity noise
更新于2025-09-12 10:27:22
-
[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Ring Interband Cascade Lasers for Environmental Monitoring
摘要： Interband cascade lasers (ICLs) combine the concept of quantum cascade lasers (QCLs) and conventional photodiodes, because they rely on the voltage-efficient in-series connection of multiple active regions as in QCLs as well as the long upper-level recombination lifetimes of photodiodes. The distinctive low power consumption of ICLs makes them especially attractive for mobile applications in the mid-infrared, such as process control, medical applications and spectroscopy. As a first proof of principle we present ICLs fabricated into ring-shaped cavities. A second order distributed feedback (DFB) grating is used for the light outcoupling of our ring ICLs, in vertical direction through the GaSb substrate. The first demonstrated devices with a waveguide width of 10 μm and 400 μm outer diameter show light emission at a wavelength of ~3.7 μm. A pulsed threshold current density <1 kA/cm2 is measured at 20°C. We are currently working on the second generation of such ring ICLs with smaller waveguides for better suppression of higher order lateral modes and larger outer diameter (e.g. 800 μm) for increased optical output power. The newly developed devices are used in a project for trace gas sensing via the principle of photothermal interferometry.
关键词： Interband cascade lasers,trace gas sensing,distributed feedback grating,photothermal interferometry,ring-shaped cavities
更新于2025-09-12 10:27:22
-
Integration of Mid-Infrared Light Sources on Silicon Based Waveguide Platforms in 3.5 — 4.7 μm Wavelength Range
摘要： Mid-infrared light sources are attracting attention for use in spectroscopic sensing, thermal imaging, and infrared countermeasures. Integration of these sources on Si-based waveguides allows for more functional and complex photonic circuits to be integrated on a single chip. This paper focuses on the key aspects of this integrated platform. The operation of silicon-on-insulator waveguides beyond 4.0 μm wavelength with increasing waveguide core thickness is discussed, and the effects of various cladding materials on waveguide propagation loss is demonstrated. Low loss waveguides and Mach-Zehnder interferometers in Ge-on-Si waveguide platform are discussed and beam combiners in the form of arrayed waveguide gratings are demonstrated in both the platforms. Interband cascade lasers are integrated on silicon-on-insulator waveguides with direct bonding to realize Fabry-Perot lasers. Power scaling of integrated lasers is validated by integrating quantum cascade lasers with silicon-on-insulator beam combiners. Results for the first integrated Fabry-Perot quantum cascade lasers on Ge-on-Si waveguides are discussed, together with the potential use of these waveguides to provide a better heat sink for integrated mid-infrared light sources.
关键词： Quantum Cascade Lasers,Silicon Photonics,Interband Cascade Lasers,Semiconductor Waveguides
更新于2025-09-11 14:15:04