Yoshiji Noguchi

50-Gb/s ring-resonator-based silicon modulator.

We achieved 50-Gb/s operation of a ring-resonator-based silicon modulator for the first time. The pin-diode phase shifter, which consists of a side-wall-grating waveguide, was loaded into the ring resonator. The forward-biased operation mode was applied, which exhibited a V(π)L as small as 0.28 V · cm at 25 GHz. The driving voltage and optical insertion loss at 50-Gb/s were 1.96 V(pp) and 5.2 dB, respectively.

12.5-Gb/s operation with 0.29-V·cm V π L using silicon Mach-Zehnder modulator based-on forward-biased pin diode

We present high-speed operation of pin-diode-based silicon Mach-Zehnder modulators that have side-wall gratings on both sides of the waveguide core. The use of pre-emphasis signals generated with a finite impulse response digital filter was examined in the frequency domain to show how the filter works for different filter parameter sets. In large signal modulation experiments, V(π)L as low as 0.29 V·cm was obtained at 12.5 Gb/s using a fabricated modulator and the pre-emphasis technique. Operation of up to 25-Gb/s is possible using basically the same driving configurations.

Compact PIN-Diode-Based Silicon Modulator Using Side-Wall-Grating Waveguide

We developed PIN-diode-based silicon Mach-Zehnder modulators, which have side-wall-gratings in the phase-shifter sections. Such passive waveguides with gratings were fabricated using ArF immersion lithography, which showed a small scattering loss of 0.4 dB/mm. We extensively investigated the forward-biased operation of the modulators by using equivalent circuit analysis and the measurement of the fabricated devices. We argue carrier recombination time only plays a minor role for the overall performance of the modulator. Dependences of the modulation efficiency on other various critical parameters are discussed. In particular, if we use relatively short phase shifter, the forward-biased operation provides smaller VπL than reversed one even at high frequency of 20 GHz, at the expense of the narrow bandwidth. Our approach enables high-speed operation up to 50 Gb/s, by using phase shifter as short as 250 μm and preemphasis signals. For 12.5-Gb/s operation, the modulator cell size was only 300 μm × 50 μm, which was suitable for the applications of high-density optical interconnects.

25-Gbps operation of silicon p-i-n Mach-Zehnder optical modulator with 100-μm-long phase shifter

We developed a high-speed Mach-Zehnder modulator with the shortest phase shifter (100-μm length) reported so far. Our modulator exhibited 25-Gbps eye-openings with an extinction ratio of 4.3 dB and on-chip insertion loss of 4.7 dB.

Demonstration of 25-Gbps optical data links on silicon optical interposer using FPGA transceiver

We demonstrated a 25-Gbps error-free data link on a silicon optical interposer. The experimental results verified that our interposer is compatible with high-performance FPGAs, and transmitter pre-emphasis and receiver equalization reduced bit error rate of the optical data link.

50-Gb/s silicon modulator using 250-µm-Long phase shifter based-on forward-biased pin diodes

We present a 50-Gb/s silicon Mach-Zehnder modulator that uses the shortest 250-μm long phase shifter. A 4.2-dB extinction ratio was obtained at 50 Gb/s with 4.35 V peak-to-peak (Vpp) driving signals and 45-mW power consumption.

12.5-Gb/s operation of efficient silicon modulator using side-wall grating waveguide

A silicon Mach-Zehnder modulator, which has side-wall-grating waveguide, is investigated. Using the fabricated device, 12.5-Gb/s operation was demonstrated. A modulation efficiency (VπL) of 0.29 V·cm was determined from the measured extinction ratio.

First demonstration of athermal silicon optical interposers with quantum dot lasers operating up to 125 °C

We demonstrated athermal silicon optical interposers integrated with quantum dot lasers at 1.3 μm, achieving a bandwidth density of 15 Tbps/cm2 with a channel line rate of 12.5 Gbps operating up to 125 °C without any bias adjustment.