About

Clint Schow is a Professor in the Department of Electrical and Computer Engineering at UC Santa Barbara. His research interests include optoelectronic and electronic integration and co-design, photonic switching, equalization techniques for high-speed optical links, optoelectronic devices, and integrated transceiver packaging. He is associated with the Schow Group and is based in the Harold Frank Hall, Rm 4155. His contact information includes a phone number (+1 805-893-2875), email (schow@ece.ucsb.edu), and office location (3205C Engineering Science Building).

Research topics

• Computer Science
• Electronic engineering
• Engineering
• Optics
• Physics
• Electrical engineering
• Telecommunications
• Optoelectronics
• Computer hardware

Selected publications

• A Monolithically Integrated Five-Segment Mach–Zehnder Modulator With Distributed Driver in 45-nm CMOS

  IEEE Photonics Technology Letters · 2025-10-30 · 1 citations

  articleSenior author

  We demonstrate a monolithically integrated O-band silicon photonics 5-segment Mach-Zehnder modulator with a distributed driver in a 45-nm CMOS process, packaged with wirebonds on a PCB. Each segment includes a cascode driver and 0.7 mm traveling-wave electrode with a termination. Open eyes and BERs below the KP-4 and KR-4 FEC threshold are measured up to 40 Gbaud with 3.09 pJ/bit energy efficiency, without feedforward equalization (FFE). Open eyes and BER below the KP-4 FEC threshold are also measured at 50 Gbaud with 2.47 pJ/bit energy efficiency using an analog 5-tap finite impulse response (FIR) equalizer. The design approach enabled a low power consumption of 116.5 mW.

  PublisherDOI

• A 100 Gbps Fully Packaged O-band Micro-ring Modulator Based Coherent Transmitter

  2025-01-01

  articleSenior author

  A fully packaged O-band coherent transmitter, comprising a fiber-attached MRM-based silicon photonic transmitter and a co-designed electronic integrated circuit on a custom PCB, achieved 100 Gbps QPSK modulation below the HD-FEC bit error rate threshold.

  PublisherDOI

• A 100 Gbps, sub-pJ/bit Transimpedance Amplifier in 90-nm SiGe in a Reconfigurable IMDD/Coherent Optical Receiver

  2025-01-01

  articleSenior author

  We report a 0.91 pJ/bit, differential dual-channel TIA with variable gain reaching 64 dBΩ in 90-nm SiGe measured in a reconfigurable PAM4/QPSK O-band receiver at 53.125 Gbaud with BERs below the KP4-FEC threshold of 2.2e-4.

  PublisherDOI

• Dual-Polarization Optical Costas Loop for DSP-Free Homodyne Short-Reach Links

  Journal of Lightwave Technology · 2025-01-24 · 1 citations

  articleOpen accessSenior author

  Here we report a dual-polarization, O-band optical phase-locked loop packaged in a footprint compatible with pluggable optics. Custom-designed analog Costas loop electronics and silicon photonic circuits, including a hybrid-integrated tunable laser serving as the local oscillator, were integrated into a functional receiver subsystem that was characterized as part of a full coherent link. The receiver frequency and phase locked loop had a bandwidth of 450 MHz and was capable of locking to frequency offsets <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$&lt; $</tex-math></inline-formula>8 GHz and tracking the local oscillator's <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm$</tex-math></inline-formula>1.5 GHz frequency drift, enabling DSP-free carrier-recovery. The entire homodyne coherent link achieved a maximum QPSK transmission rate of 112 Gb/s (56 Gbaud) for single polarization and 30 Gb/s (15 Gbaud) for dual-polarization operation. Bit error rates below hard decision forward error correction thresholds of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$3.8\cdot 10^{-3}$</tex-math></inline-formula> were achieved with 4.8 pJ/bit of transmitter and 8.8 pJ/bit of receiver power consumption, demonstrating the potential for a DSP-free solution for coherent links below 10km as an alternative to current IMDD schemes.

  PublisherDOI

• Analog coherent link with expanded link budget from integrated lasers and transmission through an O-band wavelength selective switch

  Optics Express · 2025-11-05

  articleOpen accessSenior author

  We report what is believed to be the first unamplified analog coherent link using heterogeneously integrated lasers in both the TX and RX. The link achieves a 10 dB fiber-to-fiber link budget while operating with BER below the KP-4 FEC threshold, and a 7 dB fiber-to-fiber link budget with BER below the KR-4 FEC threshold, both while transporting 100 Gbps QPSK over a single polarization. The facet-to-facet link budgets are 23 dB and 20 dB respectively. QPSK transmission is measured through an O-band silicon photonics integrated wavelength-selective switch with a BER below the Staircase FEC threshold.

  PublisherDOI

• Silicon Photonic Highly Doped Ring Modulators for Cryogenic &amp; Radiation-Hard WDM Readout

  2025-01-01

  articleSenior author

  We present a Silicon PIC with 8 λ highly doped micro-ring modulators for extreme environment optical readout. Junctions were validated at 4K and 20 MRad TID. Room temperature eye diagrams are open at 53.125 Gbps.

  PublisherDOI

• Dual-polarization O-band silicon photonics transmitter with an integrated tunable laser, Mach-Zehnder modulators, and SOAs

  Optics Express · 2024-12-02 · 2 citations

  articleOpen accessSenior author

  Presented is an O-band silicon photonics dual-polarization coherent/IMDD modulator integrated with semiconductor optical amplifiers and tunable laser to enhance the short-reach link budget. The laser demonstrated output power >6 dBm and a <250 kHz linewidth over a 14 nm tuning range. Modulators paired with custom 64 Gbaud QPSK drivers exhibited improved analog link sensitivity compared to similar devices without integrated gain sections. They also demonstrated 53 Gbaud dual-polarization PAM4 operation when characterized with a linear driver and MaxLinear 100G/lane DSP board. Both optical links achieved BERs at the KP4-FEC threshold and overall transmitter assembly energy consumption <6.9 pJ/bit without any thermal control when at steady room temperatures.

  PublisherDOI

• 400 Gbps/$\lambda$ O-Band Coherent Link Using SiP TX and RX PICs With Heterogeneously Integrated Lasers and SOAs

  Journal of Lightwave Technology · 2024-12-24 · 6 citations

  articleSenior author

  We report a net 400 Gbps/<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\lambda$</tex-math></inline-formula> O-band, dual-polarization, intradyne coherent link using silicon photonic (SiP) transmitter and receiver photonic integrated circuits (PIC) with heterogeneously integrated lasers and semiconductor optical amplifiers (SOA). Operation below the 15.3% overhead 2×10<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{-2}$</tex-math></inline-formula> open forward error correction (O-FEC) threshold was achieved for 60 Gbaud 16QAM over 2 km and 100 Gbaud QPSK over 10 km without external optical amplification. These results demonstrate the potential for implementing SiP PICs with integrated lasers and SOAs in future short-reach coherent links.

  PublisherDOI

• First Demonstration of 200-G Coherent PON at O-band with Heterogeneously-Integrated SiP Tx and Rx with Lasers

  2024-01-01 · 3 citations

  article

  We demonstrate the first 200-G O-band coherent PON using a heterogeneously-integrated SiP PIC transmitter as an OLT and PIC/EIC receivers as ONUs. A joint DSCM and NOMA scheme is presented for flexibly dense access scenarios.

  PublisherDOI

• Mixed domain coherent link with electrically reconfigurable IMDD and coherent modes for O-band data center applications

  Optics Express · 2024-09-10 · 2 citations

  articleOpen accessSenior author

  We report the first O-band link with electrically reconfigurable intensity-modulation direct-detection (IMDD) and coherent operation using custom silicon photonic chips packaged with commercial electronic chips. Transmission below the KP4-FEC threshold is shown using commercial 53 Gbaud PAM4 digital signal processing (DSP) for 16QAM (200 Gbps/λ) and PAM4 (100 Gbps/λ). Efficient operation of the packaged full link at 12 and 11.2 pJ/bit is achieved for the PAM4 and 16QAM modes, respectively.

  PublisherDOI

Frequent coauthors

• Alexander Rylyakov

  Nokia (United States)

  107 shared

• Christian Baks

  IBM Research - Thomas J. Watson Research Center

  82 shared

• Fuad E. Doany

  81 shared

• Daniel M. Kuchta

  IBM (United States)

  63 shared

• Benjamin G. Lee

  Google (United States)

  54 shared

• James F. Buckwalter

  University of California, Santa Barbara

  41 shared

• Yurii A. Vlasov

  40 shared

• Aaron Maharry

  University of California, Santa Barbara

  40 shared

Labs

• Schow GroupPI

  Not provided

Education

• Ph.D., Electrical and Computer Engineering

  The University of Texas at Austin

  1999