We report the design, fabrication, and characterization of a universal silicon PN junction ring resonator for C band error-free communication links operated up to 50 Gb/s with co-designed optical modulation and detection performance. The universal p-n junction ring device shows co-designed detection responsivity up to 0.84 A/W, in conjunction with a modulation efficiency of ∼4V·mm and >8dB optical modulation extinction ratio, enabling C band 50 Gb/s NRZ communication link with a bit error rate ≤3×10-12. Individually, the speed of modulation and detection is measured up to 112 Gb/s and 80 Gb/s, respectively. The principle of co-designing the PN junction ring modulator and detector performance required for error-free communication links can significantly ease the fabrication yield challenges of ring structures by reducing the number of types of devices. The principle can also be applied to O band wavelengths. To the best of our knowledge, for the first time, a device of this type has achieved both error-free modulation and detection operation up to 50 Gb/s in the C band individually or in conjugation as an error-free communication link, which paves the way to realize a >1.6Tb/s all-silicon WDM-based error-free optical transceiver link in the future and is essential for future programmable photonics circuits.

Here, we designed a broadband, low loss, compact, and fabrication-tolerant silicon-based four-mode edge coupler, composed of a 1×3 adiabatic mode-evolution counter-taper splitter and a triple-tip inverse taper. Based on mode conversion and power splitting, the proposed structure can simultaneously realize efficient mode coupling from TE0, TM0, TE1, and TM1 modes of multimode silicon waveguides to linearly polarized (LP), LP01,x, LP01,y, LP11a,x, and LP11a,y, modes in the few-mode fiber. To the best of our knowledge, we proposed the first scheme of four LP modes coupling, which is fully compatible with standard fabrication process. The 3D finite-difference time-domain simulation results show that the on-chip conversion losses of the four modes remain lower than 0.62 dB over the 200 nm wavelength range, and total coupling losses are 4.1 dB, 5.1 dB, 2.1 dB, and 2.9 dB for TE0-to-LP01,x, TM0-to-LP01,y, TE1-to-LP11a,x, and TM1-to-LP11a,y, respectively. Good fabrication tolerance and relaxed critical dimensions make the four-mode edge coupler compatible with standard fabrication process of commercial silicon photonic foundries.

An ultra-broadband and fabrication-tolerant silicon polarization rotator splitter is proposed in this Letter. Benefitting from the broadband and low-loss characteristics of the bi-level taper and counter-tapered coupler, the designed device has a simulated insertion loss and crosstalk of less than 0.2 and 15 dB in the waveband from 1290 to 1610 nm. These characteristics make it valuable in applications with large bandwidth requirements, such as full-grid Coarse wavelength division multiplexer (CWDM) and diplexer/triplexer fiber-to-the-home systems. The fabrication tolerance of the design is also analyzed, showing that the device performance is quite stable with normal manufacturing errors in silicon photonics foundries.