Ultracompact 40-Channel Arrayed Waveguide Grating on Silicon Nitride Platform at 860 nm

Bidirectional Coupler Study for Chip-Based Spectral-Domain Optical Coherence Tomography

“…To demonstrate all the channel output spectrum in AWG and EG [ 22 , 23 , 24 , 25 ], we used the commercial software of EPIPPROP from Photon Design to simulate the process variation effects in two waveguide length shifts, +10 and −10 nm, shown in Figure 9 and Figure 10 . The design parameters for 64-channel AWG and EG in the 1310 nm wavelength range are listed in Table 2 .…”

Dual-Polarization Bandwidth-Bridged Bandpass Sampling Fourier Transform Spectrometer from Visible to Near-Infrared on a Silicon Nitride Platform

“…However, the development of on-chip spectrometers based on photonic integrated circuits (PICs) has shown great promise in the sense that they can offer low-cost, portable, and robust spectroscopy, along with low power consumption and high reliability . In recent decades, a myriad of on-chip spectrometer devices have been demonstrated based on different operating schemes, such as dispersive optics using arrayed waveguide gratings (AWGs), − echelle grating, metasurface elements, arrayed narrow-band filters, computational spectral reconstruction-based systems, and Fourier transform spectroscopy (FTS). Dispersive spectrometers, often called grating spectrometers or scanning spectroscopy, splits the wavelengths of input light into separate spectral ranges and collects each wavelength individually.…”

“…Dispersive spectrometers, often called grating spectrometers or scanning spectroscopy, splits the wavelengths of input light into separate spectral ranges and collects each wavelength individually. A lot of grating-based devices have been studied and reported with sub-nanometer resolution in the visible (VIS) to near-infrared (NIR) range, − ,, but the gratings or slits on a dispersive device limit the amount of energy reaching the detector and the scan speed of spectroscopy because the individual wavelengths across the bandwidth have to be measured separately. Meanwhile, FTS is a technique that measures the spectrum with the interference of light instead of dispersion, so it does not separate energy into individual wavelengths for measuring the spectrum, offering advantages including high optical throughput and a multiplexing advantage, and, in turn, a larger signal-to-noise ratio (SNR) and faster data collection speed compared to the grating-based dispersive counterparts.…”

Tandem Configuration of Microrings and Arrayed Waveguide Gratings for a High-Resolution and Broadband Stationary Optical Spectrometer at 860 nm

“…These spectrometers have either wide bandwidth or high spectral resolution, but it is difficult to have both, especially at wavelengths shorter than the telecommunication bands (e.g., 1300 or 1550 nm) where impressive advances have been made for high channel count AWG spectrometers for dense wavelength division multiplexing. , Previous work in the wavelength range from 800 to 900 nm − has shown that operation at the shorter wavelengths increases the sensitivity to variations in waveguide dimensions compared with operating at longer wavelengths, increasing the challenge to fabricate high performance spectrometers. We recently reported an ultracompact 40-channel silicon nitride AWG at a center wavelength of 860 nm with a 60 nm bandwidth, but only 1.5 nm spectra resolution . While it is theoretically possible to further improve the spectral resolution and increase the wavelength channel count of an AWG, in practice, the implementation of large arrays containing the larger waveguide length increments in the array required for high resolution will result in an exponential increase in the size of AWG and will lead to the problem of accumulated phase errors in the waveguide array that will introduce higher interchannel crosstalk.…”

“…We recently reported an ultracompact 40channel silicon nitride AWG at a center wavelength of 860 nm with a 60 nm bandwidth, but only 1.5 nm spectra resolution. 24 While it is theoretically possible to further improve the spectral resolution and increase the wavelength channel count of an AWG, in practice, the implementation of large arrays containing the larger waveguide length increments in the array required for high resolution will result in an exponential increase in the size of AWG and will lead to the problem of accumulated phase errors in the waveguide array that will introduce higher interchannel crosstalk. The use of high index contrast waveguides, while offering the advantage of small bend radii for compact high channel count AWGs, also increases the sensitivity to dimensional variations in fabrication and reduces the crosstalk level to −4 dB in an ultracompact 512 channels high index-contrast silicon AWG.…”