2024/05/17 by Alexander Chen, Meng Zhang, Chen, Alexander +9
Engineering · Physics and Astronomy · #FOS: Physical sciences #Optics (physics.optics) #Photonic Crystals and Applications #Photonic and Optical Devices #Semiconductor Lasers and Optical Devices
paper · pdf · doi:10.48550/arxiv.2405.11044
openalex publication_date 2024/05/17 · openalex created_date 2024/05/22 · openalex updated_date 2026/07/28
In this research, we developed a low-power silicon photonics foundry-fabricated slow-light thermal phase shifter (SLTPS) where the slow-light (SL) effect is achieved using an integrated Bragg grating (BG) waveguide. Heating the grating induces a red shift in the transmission spectrum, leading to an increased group index ng during operation, which facilitates a further reduction in the voltage needed for a π phase shift, i.e. Vπ. Additionally, we investigated a compact Mach-Zehnder Interferometer (MZI) that incorporates the SLTPS in both arms with a phase shifter length of 50 μm. A detailed theoretical analysis was conducted to address the non-idealities of the SL-MZI due to uneven optical power splitting and unbalanced loss in the two MZI arms. The Vπ and power consumption for a π phase shift (Pπ) of the SL-MZI were quantified for operation in the slow light regime, demonstrating a Vπ of 1.1 V and a Pπ of 3.63 mW at an operational wavelength near the photonic band edge. The figure of merit (FOM) Pπ × τ is commonly used to assess the performance of thermal optical switches. The SL-MZI in this work has achieved a low Pπ × τ of 5.1 mW μs. Insertion loss of the SL-MZI ranges from 1.3 dB to 4.4 dB depending on the operation wavelength, indicating a trade-off with the Vπ reduction.