Demonstration of Silicon-on-insulator mid-infrared spectrometers operating at 38μm

Abstract

Abstract:The design and characterization of silicon-on-insulator midinfrared spectrometers operating at 3.8μm is reported. The devices are fabricated on 200mm SOI wafers in a CMOS pilot line. Both arrayed waveguide grating structures and planar concave grating structures were designed and tested. Low insertion loss (1.5-2.5dB) and good crosstalk characteristics (15-20dB) are demonstrated, together with waveguide propagation losses in the range of 3 to 6dB/cm.

Optically Pumped GeSn Microdisk Lasers on Si

“…12 Moreover, it will allow for the integration of lasers on the same Si chip and thus for the embedding of photonic architectures into Si microtechnology. 13,14 Besides its technological and socio-economic impact, and in spite of promising steps made in the last few years, 15 the realization of a group IV integrated light source poses fascinating scientific challenges in order to overcome the physical limitation of the fundamental indirect bandgap group IV elements Si and Ge to efficiently generate light. Great efforts have been made to modify these materials, e.g.…”

Integrated Microspectrometer with Elliptical Bragg Mirror Enhanced Diffraction Grating on Silicon on Insulator

“…Finally the efficiency of the diffraction grating itself could not be estimated at this stage due to the several possible sources of loss in the whole spectrometer previously mentioned, but is expected to be high from the precise FDTD estimation. For comparison, other CDG spectrometers have an average efficiency of -3.2 dB, with a range from -5.0 dB to -1.6 dB, as claimed, 14,[19][20][21]24,25,29,30,[33][34][35] and have an average channel uniformity (over a band equivalent to 30 nm at 1550 mn) of 0.9 dB, with a range from 1.5 dB to 0.2 dB. 14,[19][20][21]24,25,29,30,[33][34][35] This places the present spectrometer within the state of the art for efficiency and at a high level for uniformity.…”

“…The two principal integrated components commonly employed for this purpose are the arrayed waveguide grating (AWG) [10][11][12][13][14][15] and the concave diffraction grating (CDG), 8,11,14,[16][17][18][19][20][21][22][23][24][25] often referred as echelle grating. The AWG consists of (i) an input waveguide, (ii) a laterally free propagation region where the beam expands and couples to (iii) an array of waveguides that exhibit variable path lengths and hence path phase differences, after which the waveguides are coupled to (iv) a second laterally free propagation region (star coupler) and recombine and focus into (v) a set of output waveguides that are discriminated in wavelength due to the accumulated phase profile in the waveguide array section.…”

Silicon-Based Photonic Integration Beyond the Telecommunication Wavelength Range

“…Using this technology very low waveguide losses (∼0.5 dB/cm) in the 2-2.5-μm wavelength range have been obtained [8]. Similarly, on the 400 nm silicon waveguide platform 3-dB/cm waveguide losses at a wavelength of 3.8 μm were obtained [9]. Besides low-loss waveguides, functional components for spectroscopic sensing systems were also demonstrated [10], including planar concave grating spectrometers and arrayed waveguide gratings in the 2-2.5 μm [11] and 3.8-μm wavelength range [9].…”

“…Similarly, on the 400 nm silicon waveguide platform 3-dB/cm waveguide losses at a wavelength of 3.8 μm were obtained [9]. Besides low-loss waveguides, functional components for spectroscopic sensing systems were also demonstrated [10], including planar concave grating spectrometers and arrayed waveguide gratings in the 2-2.5 μm [11] and 3.8-μm wavelength range [9]. The transmission spectrum of a silicon-on-insulator wavemeter (a wavelength demultiplexer circuit where the output channels intentionally overlap in order to accurately measure the wavelength of a laser line injected into the spectrometer through centroid detection) based on an arrayed waveguide grating is shown in Fig.…”