Integration of Black Phosphorus Photoconductors with Lithium Niobate on Insulator Photonics

Abstract

Photodetectors formed with layered two‐dimensional (2D) materials have shown significant potential for integration with photonic circuits, offering fast, high responsivity and low noise detection over a broad range of optical wavelengths. However, only preliminary trials of this concept have been performed on emerging photonics platforms such as lithium niobate on insulator (LNOI). In this study, a novel architecture consisting of ≈15 nm thick layered black phosphorus (bP) photoconductors draped over LNOI waveguides is demonstrated. The performance of these detectors is studied across the telecom bands at room temperature, and a high extrinsic responsivity of 148 mA W−1 is measured at λ = 1550 nm under low bias conditions (VDS = 0.3 V). The spectral response of the detectors is broad allowing the response of other photonic components, such as fiber‐to‐chip grating couplers, to be characterized in situ, without need to out‐couple the light. Finally, the speed of the bP detectors is found to be beyond our instrumentation, setting 100 ns as an upper‐limit rise/fall time, with the actual speed of the bP detector likely to be much faster.

Ultrasensitive Bidirectional Photoresponse SnSe2 Photodetector Integration with Thin‐Film Lithium Niobate Photonics

“…The comparison of the response wavelength and responsivity of our PD with those of waveguide PDs based on the SOI/TFLN/Si 3 N 4 platform reported in the literature is shown in Figure 7. [34,35,[55][56][57][58][59][60][61][62][63][64][65][66][67][68] Detailed comparisons can be found in Table S2, Supporting Information. In addition, we compare the performance of our PD with that of PDs based on the SnSe 2 2D material, as shown in Table S3, Supporting Information.…”

“…A few 2D materials and semiconductor materials have been integrated into TFLN for use in PDs, but the responsivity is still low. [34,35] Extracting multiple carriers from a single photon through the charge trapping mechanism to increase the photogain is an effective approach for achieving high responsivity. [36] Broadband light detection is another important developing trend in PD technology that facilitates large-format integration.…”

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

“…In addition to the rapid development of various photoelectric devices of LN thin-film platforms, the realization of on-chip light sources will undoubtedly make the LN thin-film platform achieve a high degree of integration. At the same time, detectors based on Si, 165 black phosphorus, 166,167 and superconducting nanowires 168,169 have been proven on the LNOI platform, demonstrating the feasibility of integrated photodetectors. Furthermore, the experience of heterogeneously integrated III-V photodetectors based on Si-based photonics can also be transferred into the LN thin-film platform and is expected to achieve high detector bandwidth.…”

On-chip two-dimensional material-based waveguide-integrated photodetectors

“…7(c). 203 This device exhibited a responsivity of up to 148 mA W −1 and a bandwidth of more than 3.5 MHz at the wavelength of 1.55 μm. However, due to process limitations, lithium niobate waveguides are usually in the form of ridge waveguides and have non-vertical sidewalls (usually at an angle of 60°) to prevent 2DM fracture.…”