Special issue-Mid-infrared integrated optoelectronic technology
2022, 51(3): 20220106.
doi: 10.3788/IRLA20220106
In recent year, mid-wave infrared detection technology has rapid development, and plays an important role in variable applications. Among different kinds of mid-infrared detectors, Ga-free InAs/InAsSb type II superlattice (T2 SL) detectors have the potential to achieve higher minority carrier lifetime and higher performance due to the removal of Ga-related defects. The application of photonic crystals is another way to improve the performance of detectors by optical control, such as the improvement of responsibility and the decrease of the dark current. With higher responsibility and lower dark current, the detector can have higher operating temperature, which results in low Size, Weight and Power (SWaP). At the same time, the photonic crystals can also realize the optimization of optical performance such as broadband spectrum responsibility without changing the material structure. The material growth and device design of InAs/InAsSb T2 SL detectors and photonic crystal structure detectors were reviewed and discussed in this paper. Two methods to improve the performance and the progress of mid-wave infrared detectors were introduced in detail.
2022, 51(3): 20220152.
doi: 10.3788/IRLA20220152
In recent years, chalcogenide glasses have attracted much attention in the field of integrated photonic devices because of their ultra-wide infrared transmission spectrum, high linear refractive index, extremely high optical nonlinearity, and ultrafast nonlinear response. Firstly, the fabrication of chalcogenide glass integrated optical waveguides was reviewed, the progress of chalcogenide integrated photonic devices in infrared sensing and high-performance nonlinear applications was summarized. Then, the chalcogenide phase-change photonic devices in optical switching, optical storage, and optical computing were introduced. Finally, the current problems in chalcogenide glass photonic devices were summarized, and the future research directions were prospected.
2022, 51(3): 20220197.
doi: 10.3788/IRLA20220197
Mid-infrared photonic integrated circuits have been attracting a lot of interest for applications in environmental monitoring, medical diagnosis and national defense. However, the integration of laser sources with low-loss mid-infrared waveguide circuits is challenging. Quantum cascade lasers (QCLs) are important semiconductor laser sources operating in the mid-infrared spectral range. In this review paper, the research progress of the photonics integration of mid-infrared QCLs in recent years was introduced. Several different approaches were reviewed, including monolithic integration on InP, monolithic integration on silicon, heterogeneous integration on silicon and III-V/Germanium hybrid external cavity laser.
2022, 51(3): 20220021.
doi: 10.3788/IRLA20220021
Silicon-based photonics is expected to be extended to the mid-infrared (MIR) wavelength, due to the low absorption of silicon (Si) material in the range of 1.1 μm to 8.5 μm. With the needs emergence of communication window expansion, gas molecular detection, infrared imaging and other applications, the development of silicon-based devices in the mid-infrared wavelength is imperative. Silicon-based modulator plays an important role in the research and development of silicon-based optoelectronic devices in MIR. It is an indispensable link in long wave optical communication system, and can be used in on-chip sensing system to improve the signal-to-noise ratio and realize optical switching. It is found that silicon and germanium materials have greater free carrier effect and thermal-optical effect in the MIR band than that in the near-infrared band (NIR). It is proved that silicon-based materials have unique advantages in the development of mid-infrared modulators. The development trend and research status of MIR silicon-based modulators were summarized. The working principle and latest research progress of electro-optic modulators and thermal-optic modulators based on silicon and germanium materials were introduced. Finally, the mid-infrared silicon-based modulators were summarized and prospected.
2022, 51(3): 20220092.
doi: 10.3788/IRLA20220092
The 2 μm wavelength band, which is the closest to the O and C communication band in the mid-infrared band, has gradually attracted widespread attention. A Mach-Zehnder modulator in the wavelength of 2 μm was optimally designed and simulated. According to the distribution characteristics of the optical mode field in the wavelength of 2 μm, an SOI substrate with the top silicon thickness of 340 nm was selected. Combined with the process of the etching depth of 240 nm, the optimal rib waveguide width was 600 nm and the thickness of the slab layer was 100 nm. By optimizing the doping concentration and the positions of the doping regions, an optimal overall performance of the modulator was obtained. The modulator operated with the static extinction ratio of 23.8 dB, the optical loss of 5.34 dB/cm, the modulation efficiency of 2.86 V·cm and the 3 dB EO bandwidth of 27.1 GHz at the reverse bias of 4 V. Besides, compared with the device with the top silicon thickness of 220 nm, the overall performance of the modulator was more superior. The research content provides a basis of the device tape-out, and also provides a new idea for the design of the modulator required for the 2 μm band optical transceiver integrated module.
2022, 51(3): 20210969.
doi: 10.3788/IRLA20210969
Optical frequency comb is a kind of broad spectrum coherent light source, which is composed of a series of discrete spectral lines with equal frequency interval and has ultrahigh time-frequency accuracy. Since its birth, optical frequency comb has brought revolutionary changes to the development of precision spectroscopy, optical measurement, coherent optical communication, optical clock and other applications. In recent years, researchers have extended the frequency comb to the mid-infrared spectrum region (2-20 μm) by using novel laser gain media, nonlinear frequency conversion and micro-resonator techniques, and further expand the application range of optical frequency comb. In this paper, the generation mechanism, latest development and application of mid-infrared frequency comb are introduced.
2022, 51(3): 20220087.
doi: 10.3788/IRLA20220087
Driven by the development in big data services, the conventional optical fiber communication window was shifting from C-band to C+L band to meet the continuously increasing demand for bandwidths. Exploiting new wavebands became a crucial problem within the optical communications community. The 2 μm spectral range between near-infrared and mid-infrared held advantages of low transmission loss and broad gain bandwidth, which made it a promising candidate for the next window of free space laser and optical fiber communications. Even though the commercialization of the 2 μm optoelectronic devices was at early stage, recorded single-lane 100 Gbit/s transmission had been achieved in the laboratory. In the meantime, developing functional elements in this wavelength range was attracting extensive interests. In this paper, the recent advances of 2 μm silicon photonic device were introduced. Photonic integrated components on other platforms like III-V, thin-film lithium niobate, silicon nitride, and chalcogenide glass were also discussed. Finally, the 2 μm was envisioned on-chip photonic integrated devices.
2022, 51(3): 20220043.
doi: 10.3788/IRLA20220043
Short-wavelength mid-infrared (mid-IR) (2-2.5 μm wavelengths) photonics has tremendous applications in optical communication, ranging, satellite remote sensing, disease diagnosis, and military defense. As key components of short-wavelength mid-IR optical systems, integrated optoelectronic devices have attracted great attention in the past decades. With the merit of the wide transparency window of silicon material, silicon photonic integrated circuits exhibit great potential in developing short-wavelength mid-IR optoelectronic devices. In this review paper, we briefly discuss potential applications of short-wavelength mid-IR silicon photonics, and review its history and frontier progress from three aspects, namely, passive waveguide devices, nonlinear optics waveguide devices, and optoelectronic waveguide devices.
2022, 51(3): 20220104.
doi: 10.3788/IRLA20220104
In recent years, mid-infrared (wavelength range of 2–20 μm) integrated photonics has received a lot of attention for its potential applications, including absorption spectroscopy, thermal imaging, and free-space communication. The mid-infrared, which includes several atmospheric transparency windows, has an inherent advantage for sensing applications. The mid-infrared photonic devices also benefit from the mature technologies developed in the near-infrared for device design, test, and fabrication. In addition, integrated photonic sensors have demonstrated comparable sensitivity to their bulk counterparts, while featuring low power consumption, low cost, compact structure, and easy integration with other devices. Therefore, the mid-infrared integrated photonic sensors will play an important role in industrial detection, scientific research, medical diagnosis, military security, life, and other fields in the future. Here, Recent advances in the mid-infrared integrated photonic sensors have been reviewed. Three major components, sensing unit, spectrometer, and detector were discussed. An outlook for its future development was also proposed.
2022, 51(3): 20220082.
doi: 10.3788/IRLA20220082
The mid-infrared band contains two atmospheric windows as well as the molecular fingerprint region, and therefore has important applications in infrared imaging and detection. Conventional mid-infrared optics are expensive and need complicated fabrications limited by the material and processing technology in imaging. In terms of the detection, limited by the small molecular absorption cross-section, the sensitivity is extremely low and there is a great challenge for the trace chemical detection. Metasurfaces are two-dimensional arrays composed of artificial building blocks at the subwavelength scale. They have the characteristics of small size, easy integration and high degree of freedom, which may provide a new implementation scheme for manufacturing the low-cost, light-weight and integrated mid-infrared optical devices. Surface-enhanced infrared absorption can effectively enhance molecular vibration signals and improve the detection sensitivity. In this review, the mechanism of mid-infrared metasurfaces in electromagnetic wave regulation and the principals of mid-infrared detection applications are introduced. The research progress in the imaging and detection of mid-infrared metasurfaces is sorted out, including the polarization imaging, tunable and reconfigurable metasurfaces, other special functions and metasurface structures using gold, silver, aluminum, graphene, silicon, germanium and other materials based on plasmon or bound states in the continuum principles for the detection.
