Brian Stern

We show a lead lanthanum zirconate titanate (PLZT) integrated photonics platform, demonstrating grating couplers and microring resonators using this emerging material which is desirable for its high Pockels coefficient. Grating coupling efficiency of -6.9 dB and resonator quality factors of 8.6×10 ⁴ are shown.

We experimentally demonstrate a carrierless and local oscillator (LO)-free transmission over 100-km single-mode fiber (SMF) with 100-GBaud dual-polarization (DP) probabilistically shaped (PS)-64QAM at 5.6-bit/symbol entropy via a 100-GHz phase retrieval (PR) receiver, achieving a net rate of 835 Gb/s and an 8.27-b/s/Hz net optical spectral efficiency (OSE). Additionally, we also demonstrate 50-GBaud DP PS-256QAM transmission with 7.2 bits/symbol entropy over 40 km of standard SMF, achieving a net bit rate of 533 Gb/s and a net OSE of 10.55 b/s/Hz. In the discussion, a comparison with other reported transmission experiments utilizing direct detection (DD) and complex-field reconstruction techniques highlights the carrierless PR scheme's advantages in optical signal-to-noise-ratio (OSNR)-constrained links, particularly by conserving optical power typically allocated for carrier transmission. The carrierless PR reception demonstrates direct compatibility with coherent modulation formats and transmitters without sacrificing the effective OSNR, and it may offer a direct detection-based, wavelength-independent, LO-free, and coherent-compatible solution for future data center and metropolitan network interconnections.

We demonstrate nanosecond-scale measurements of laser wavelength using an integrated silicon wavemeter covering a 95 nm range with high accuracy. We measure the wavelengths of multiple alternating, bursting lasers within 10 ns.

We demonstrate a silicon photonic wavemeter with nanosecond-scale measurement speed. We show tracking of the frequency excursions of a laser during bursts and steps, with wavemeter response times of 3 ns.

We demonstrate an integrated dual-polarization phase retrieval receiver. It uses silicon waveguides and resonators to recover phase from intensity-only measurements. We show retrieval of a polarization-division multiplexed 30-GBd QPSK signal over 80 km of SSMF.

We demonstrate an athermal silicon photonic wavemeter with high accuracy for broadband measurements over the temperature range 20-70°C. The integrated wavemeter has an average accuracy of 7.9 pm (<1 GHz) across the C-band.

We demonstrate a silicon photonic Bragg grating waveguide with a large dispersion of ‑146 ps/nm and 171 GHz bandwidth. Using an integrated phase shifter array, the grating is tuned to reduce ripple nearly threefold.

We demonstrate a silicon photonic wavemeter with high accuracy for broadband measurements over a large temperature range of 20-60˚C. The integrated wavemeter reaches a mean error of 11 pm over an 80 nm span.

Optical devices that introduce and compensate for dispersion serve an important role in communication networks, photonic signal processing, and nonlinear optics. In this article, we demonstrate a silicon photonic Bragg grating which simultaneously achieves a large dispersion and wide bandwidth. We measure the grating to have a dispersion of −146 ps/nm over a 171 GHz bandwidth, representing the highest demonstrated grating dispersion over this wide bandwidth in a standard thickness silicon photonics process. Additionally, we show a significant reduction of group delay ripple by tuning the grating using an integrated phase shifter array to address fabrication variations. We further use the silicon grating as a dispersive element in a direct-detection phase retrieval receiver for 40 GBd quadrature phase shift keying (QPSK) signals and achieve a bit error rate (BER) below the 20% forward error correction (FEC) threshold. These results establish the potential for scalable silicon photonic circuits leveraging large dispersion for optical communication and other applications.

We demonstrate a silicon Bragg grating with a large dispersion of -146 ps/nm and reduced ripple using a phase shifter array. We use the grating in a direct-detection phase retrieval receiver for 40-GBd QPSK signals.