40 Gb/s silicon photonics modulator for TE and TM polarisations

X-Intersected Silicon Modulator of Well-Rounded Performance

In silicon modulator design, implantation is always a key factor, significantly influencing the doping profile and carrier distribution. As waveguide doping is limited by the compact footprint of the modulator rib, three-dimensional complex optimization is a viable option to improve performance. This work proposes an X-intersected modulator based on two inversely slanted junctions using the effective 3D Monte Carlo method for junction generation. The optimized results show that the modulation efficiency of the design is 1.09 V·cm, while the loss is 18 dB/cm, and the 3 dB bandwidth reaches over 35 GHz owing to the decreased resistance and capacitance of the 3D junction. This work demonstrates the benefits of 3D doping design in silicon modulators, contributing to higher efficiency and avoiding additional PN overlap to introduce lower capacitance. The design of 3D doping profiles well balances the DC and AC performance, and provides novel modulator solutions for high-speed datacom.

High-performance Ge/Si electro-absorption optical modulator up to 85°C and its highly efficient photodetector operation

We studied a high-speed Ge/Si electro-absorption optical modulator (EAM) evanescently coupled with a Si waveguide of a lateral p-n junction for a high-bandwidth optical interconnect over a wide range of temperatures from 25 °C to 85 °C. We demonstrated 56 Gbps high-speed operation at temperatures up to 85 °C. From the photoluminescence spectra, we confirmed that the bandgap energy dependence on temperature is relatively small, which is consistent with the shift in the operation wavelengths with increasing temperature for a Ge/Si EAM. We also demonstrated that the same device operates as a high-speed and high-efficiency Ge photodetector with the Franz-Keldysh (F-K) and avalanche-multiplication effects. These results demonstrate that the Ge/Si stacked structure is promising for both high-performance optical modulators and photodetectors integrated on Si platforms.

High-efficiency and high-speed narrow-width MOS capacitor-type Si optical modulator with TM mode excitation

We developed a high-speed and high-efficiency narrow-width metal-oxide-semiconductor (MOS) capacitor-type Si optical modulator (Si-MOD) by applying TM optical mode excitation. We designed and fabricated an optical-mode-converter structure from TE to TM mode. Even in the case of a 200-nm width, the Si MOS-MOD showed high-modulation efficiency in TM mode (about 0.18 Vcm), and the electrical capacitance decreased as the MOS junction width decreased. We also demonstrated high-speed operation at 32 Gbps and 40 Gbps for the 30-µm-long Si MOS-MOD in TM mode.

Heterogeneously integrated ITO plasmonic Mach-Zehnder interferometric modulator on SOI

Densely integrated active photonics is key for next generation on-chip networks for addressing both footprint and energy budget concerns. However, the weak light-matter interaction in traditional active Silicon optoelectronics mandates rather sizable device lengths. The ideal active material choice should avail high index modulation while being easily integrated into Silicon photonics platforms. Indium tin oxide (ITO) offers such functionalities and has shown promising modulation capacity recently. Interestingly, the nanometer-thin unity-strong index modulation of ITO synergistically combines the high group-index in hybrid plasmonic with nanoscale optical modes. Following this design paradigm, here, we demonstrate a spectrally broadband, GHz-fast Mach–Zehnder interferometric modulator, exhibiting a high efficiency signified by a miniscule V_πL of 95 V μm, deploying a one-micrometer compact electrostatically tunable plasmonic phase-shifter, based on heterogeneously integrated ITO thin films into silicon photonics. Furthermore we show, that this device paradigm enables spectrally broadband operation across the entire telecommunication near infrared C-band. Such sub-wavelength short efficient and fast modulators monolithically integrated into Silicon platform open up new possibilities for high-density photonic circuitry, which is critical for high interconnect density of photonic neural networks or applications in GHz-fast optical phased-arrays, for example.

High-speed Ge/Si electro-absorption optical modulator in C-band operation wavelengths

We studied a high-speed electro-absorption optical modulator (EAM) of a Ge layer evanescently coupled with a Si waveguide (Si WG) of a lateral pn junction for high-bandwidth optical interconnect. By decreasing the widths of selectively grown Ge layers below 1 µm, we demonstrated a high-speed modulation of 56 Gbps non-return-to-zero (NRZ) and 56 Gbaud pulse amplitude modulation 4 (PAM4) EAM operation in the C-band wavelengths, in contrast to the L-band wavelengths operations in previous studies on EAMs of pure Ge on Si. From the photoluminescence and Raman analyses, we confirmed an increase in the direct bandgap energy for such a submicron Ge/Si stack structure. The operation wavelength for the Ge/Si stack structure of a Ge/Si EAM was optimized by decreasing the device width below 1-µm and setting the post-growth anneal condition, which would contribute to relaxing the tensile-strain of a Ge layer on a Si WG and broadening the optical bandwidths for Franz-Keldysh (FK) effect with SiGe alloy formation.

Asymmetric direct detection of orthogonal offset carriers assisted polarization multiplexed single-sideband signals

We propose and demonstrate the asymmetric direct detection (ADD) of polarization division multiplexed single-sideband (PDM-SSB) signals with orthogonal offset carriers. ADD exploits the photocurrent difference to eliminate the Y-Pol interference in the X-Pol, and the X-Pol signal intensity to eliminate the X-Pol interference in the Y-Pol without resorting to iterative algorithms. This enables not only low-complexity signal linearization but also a simplified receiver front-end composed of a single optical filter, two single-ended photodiodes and two analog-to-digital converters (ADC). In the experiment, we first perform a parametric study of the proposed scheme at 40 Gbaud in the back-to-back configuration (B2B) to evaluate the performance impact of different system parameters including the carrier to signal power ratio (CSPR), the matched filter roll-off, and the filter guard band. Next, we demonstrate the transmission of 416 Gbit/s PDM 16-QAM signal over 80 km single-mode fiber (SMF) below the soft-decision forward error correction (SD-FEC) threshold of 2×10^-2. We also numerically study the effectiveness of a 2×2 multiple-input-multiple-output MIMO equalizer in alleviating the inter-polarization linear crosstalk resulting from the non-orthogonal PDM-SSB signals due to polarization-dependent loss (PDL), which is not negligible for potential on-chip implementation of ADD.

Design of a 90 GHz SOI Fin Electro-Optic Modulator for High-Speed Applications

Introducing high speed networks, such as the fifth generation of mobile technology and related applications including the internet of things, creates a pressing demand for hardware infrastructure that provides sufficient bandwidth. Here, silicon-based microwave-photonics presents a solution that features easy and inexpensive fabrication through a mature platform that has long served the electronics industry. In this work, the design of an electro-optic modulator is proposed where the ‘fin’ structure is adopted from the domain of electronics devices, with emphasis on the high speed of operation. The proposed modulator is customized to provide a bandwidth of 90 GHz with a small phase shifter length of 800 μm and an optical insertion loss of 4 dB. With such a speed, this proposed modulator fits high-speed applications such as modern tele-communications systems.

Ultracompact CMOS-compatible optical logic using carrier depletion in microdisk resonators

We present a CMOS-compatible optoelectronic directed logic architecture that achieves high computational throughput (number of operations per second per unit area) by its ultracompact form factor. High speed-to-power performance is also achieved, by the low capacitance and high junction-to-mode overlap of low-radii SOI vertical pn junction microdisk switches. By using wavelength-division multiplexing and two electrical control signals per disk, each switch performs (N)OR, (N)AND, and X(N)OR operations simultaneously. Connecting multiple switches together, we demonstrate higher-order scalability in five fundamental N-bit logic circuits: AND/OR gates, adders, comparators, encoders, and decoders. To the best of our knowledge, these circuits achieve the lowest footprint of silicon-based multigigabit-per-second optical logic devices in literature.

Optical and electrical trade-offs of rib-to-contact distance in depletion-type ring modulators

We present a study on electrical and optical trade-offs of the doping map in a ring modulator. Here, we investigate the effects of the high-doped region distance to edge of the waveguide sidewall. Four groups of ring modulators with different rib-to-contact distances are fabricated and measured where the key parameters such as extinction ratio, insertion loss, transmission penalty, and bandwidth are compared quantitatively. Small-signal responses for the selected ring modulators are simulated where results are in agreement with measurement results. We show that, at 4dB extinction ratio, decreasing the high-doped region distance to rib from 800nm to 350nm will increase the bandwidth by 3.8 ×. However, we observed 8.4dB increase the insertion loss. We also show that the high-doped region location affects the trade-off between bandwidth and frequency response magnitude at low frequencies. At 350nm, this trade off is 2.5 × and 3.8× more efficient compared to 550nm and 800nm, respectively.

U-shaped PN junctions for efficient silicon Mach-Zehnder and microring modulators in the O-band

We demonstrate U-shaped silicon PN junctions for energy efficient Mach-Zehnder modulators and ring modulators in the O-band. This type of junction has an improved modulation efficiency compared to existing PN junction geometries, has low losses, and supports high-speed operation. The U-shaped junctions were fabricated in an 8" silicon photonics platform, and they were incorporated in travelling-wave Mach-Zehnder modulators and microring modulators. For the high-bandwidth Mach-Zehnder modulator, the DC V_πL at -0.5 V bias was 4.6 V·mm. It exhibited a 3dB bandwidth of 13 GHz, and eye patterns at up to 24 Gb/s were observed. A V_πL as low as ~2.6 V·mm at a -0.5 V bias was measured in another device. The ring modulator tuning efficiency was 40 pm·V^-1 between 0 V and -0.5 V bias. It had a 3-dB bandwidth of 13.5 GHz and open eye patterns at up to 13 Gb/s were measured. This type of PN junctions can be easily fabricated without extra masks and can be incorporated into generic silicon photonics platforms.

Flip-chip integrated silicon Mach-Zehnder modulator with a 28nm fully depleted silicon-on-insulator CMOS driver

We present a silicon electro-optic transmitter consisting of a 28nm ultra-thin body and buried oxide fully depleted silicon-on-insulator (UTBB FD-SOI) CMOS driver flip-chip integrated onto a Mach-Zehnder modulator. The Mach-Zehnder silicon optical modulator was optimized to have a 3dB bandwidth of around 25 GHz at -1V bias and a 50 Ω impedance. The UTBB FD-SOI CMOS driver provided a large output voltage swing around 5 V_pp to enable a high dynamic extinction ratio and a low device insertion loss. At 44 Gbps, the transmitter achieved a high extinction ratio of 6.4 dB at the modulator quadrature operation point. This result shows open eye diagrams at the highest bit rates and with the largest extinction ratios for silicon electro-optic transmitter using a CMOS driver.

First demonstration of SiGe-based carrier-injection Mach-Zehnder modulator with enhanced plasma dispersion effect

We demonstrate a strained Si0.91Ge0.09-based carrier-injection Mach-Zehnder (MZ) optical modulator using the enhanced plasma dispersion effect in strained SiGe through mass modulation for the first time. The SiGe modulator has an injection current of 1.47 mA for a phase shift of π which is lower than that for a Si modulator. Also, it is expected that the injection current can be further reduced by increasing the strain and Ge fraction, enabling operation at an injection current of less than 1 mA. As an example of the dynamic characteristics, 10 Gbps modulation with clear eye opening was obtained by the pre-emphasis method.

Electro-optic directed XOR logic circuits based on parallel-cascaded micro-ring resonators

We report an electro-optic photonic integrated circuit which can perform the exclusive (XOR) logic operation based on two silicon parallel-cascaded microring resonators (MRRs) fabricated on the silicon-on-insulator (SOI) platform. PIN diodes embedded around MRRs are employed to achieve the carrier injection modulation. Two electrical pulse sequences regarded as two operands of operations are applied to PIN diodes to modulate two MRRs through the free carrier dispersion effect. The final operation result of two operands is output at the Output port in the form of light. The scattering matrix method is employed to establish numerical model of the device, and numerical simulator SG-framework is used to simulate the electrical characteristics of the PIN diodes. XOR operation with the speed of 100Mbps is demonstrated successfully.

Next generation device grade silicon-germanium on insulator

High quality single crystal silicon-germanium-on-insulator has the potential to facilitate the next generation of photonic and electronic devices. Using a rapid melt growth technique we engineer tailored single crystal silicon-germanium-on-insulator structures with near constant composition over large areas. The proposed structures avoid the problem of laterally graded SiGe compositions, caused by preferential Si rich solid formation, encountered in straight SiGe wires by providing radiating elements distributed along the structures. This method enables the fabrication of multiple single crystal silicon-germanium-on-insulator layers of different compositions, on the same Si wafer, using only a single deposition process and a single anneal process, simply by modifying the structural design and/or the anneal temperature. This facilitates a host of device designs, within a relatively simple growth environment, as compared to the complexities of other methods, and also offers flexibility in device designs within that growth environment.

Strain-induced enhancement of plasma dispersion effect and free-carrier absorption in SiGe optical modulators

The plasma dispersion effect and free-carrier absorption are widely used to change refractive index and absorption coefficient in Si-based optical modulators. However, the weak free-carrier effects in Si cause low modulation efficiency, resulting in large device footprint and power consumption. Here, we theoretically and experimentally investigate the enhancement of the free-carrier effects by strain-induced mass modulation in silicon-germanium (SiGe). The application of compressive strain to SiGe reduces the conductivity effective mass of holes, resulting in the enhanced free-carrier effects. Thus, the strained SiGe-based optical modulator exhibits more than twice modulation efficiency as large as that of the Si modulator. To the best of our knowledge, this is the first demonstration of the enhanced free-carrier effects in strained SiGe at the near-infrared telecommunication wavelength. The strain-induced enhancement technology for the free-carrier effects is expected to boost modulation efficiency of the most Si-based optical modulators thanks to high complementary metal-oxide-semiconductor (CMOS) compatibility.

Compact-sized high-modulation-efficiency silicon Mach-Zehnder modulator based on a vertically dipped depletion junction phase shifter for chip-level integration

We present small-sized depletion-type silicon Mach-Zehnder (MZ) modulator with a vertically dipped PN depletion junction (VDJ) phase shifter based on a CMOS compatible process. The fabricated device with a 100 μm long VDJ phase shifter shows a VπLπ of ∼0.6  V·cm with a 3 dB bandwidth of ∼50  GHz at -2  V bias. The measured extinction ratios are 6 and 5.3 dB for 40 and 50  Gb/s operation under 2.5  Vpp differential drive, respectively. On-chip insertion loss is 3 dB for the maximum optical transmission. This includes the phase-shifter loss of 1.88  dB/100  μm, resulting mostly from the extra optical propagation loss through the polysilicon-plug structure for electrical contact, which can be readily minimized by utilizing finer-scaled lithography nodes. The experimental result indicates that a compact depletion-type MZ modulator based on the VDJ scheme can be a potential candidate for future chip-level integration.

Low temperature Al2O3 surface passivation for carrier-injection SiGe optical modulator

Surface passivation by Al(2)O(3) deposited by atomic layer deposition (ALD) at 200 °C is examined to suppress surface recombination for carrier-injection SiGe optical modulators. We have investigated the interface trap densities at SiO(2)/Si and Al(2)O(3)/Si interfaces formed by plasma enhanced chemical vapor deposition (PECVD) and ALD, respectively. By evaluating metal-oxide-semiconductor (MOS) capacitors formed on Si surfaces after dry etching, we found that the interface trap density of Al(2)O(3) passivated surface is more than one order of magnitude less than that of SiO(2) passivated one. As a result, the modulation efficiency is improved by 1.3 by inserting Al(2)O(3) layer prior to SiO(2) deposition by PECVD owing to superior interface between Al(2)O(3) and Si. The Al(2)O(3) passivated device exhibits comparable modulation efficiency to a thermally-grown SiO(2) passivated one formed by dry oxidation. Hence, the ALD Al(2)O(3) passivation is effective to passivate SiGe optical modulators for which low temperature processes are required.

Demonstration of electro-optic half-adder using silicon photonic integrated circuits

We report a silicon photonic integrated circuit which can perform the operation of half-adder based on two cascaded microring resonators (MRRs). PIN diodes embedded around MRRs are employed to achieve the carrier injection modulation. Two electrical pulse sequences representing the two operands of the half-add operation are applied to PIN diodes to modulate two MRRs through the plasma dispersion effect. The final operation results of bitwise Sum and Carry operation are output at two different output ports of the device. Microheaters fabricated on the top of MRRs are employed to compensate two MRRs resonance mismatch caused by the fabrication error through the thermo-optic effect. Addition operation of two bits with the operation speed of 100 Mbps is demonstrated.

Low power 50 Gb/s silicon traveling wave Mach-Zehnder modulator near 1300 nm

The wavelength band near 1300 nm is attractive for many telecommunications applications, yet there are few results in silicon that demonstrate high-speed modulation in this band. We present the first silicon modulator to operate at 50 Gbps near 1300 nm. We demonstrate an open eye at this speed using a differential 1.5 V(pp) signal at 0 V reverse bias, achieving an energy efficiency of 450 fJ/bit.

Low loss 40 Gbit/s silicon modulator based on interleaved junctions and fabricated on 300 mm SOI wafers

We demonstrate high-speed silicon modulators based on carrier depletion in interleaved pn junctions fabricated on 300 mm-SOI wafers using CMOS foundry facilities. 950 µm-long Mach Zehnder (MZ) and ring resonator (RR) modulator with a 100 µm radius, were designed, fabricated and characterized. 40 Gbit/s data transmission has been demonstrated for both devices. The MZ modulator exhibited a high extinction ratio of 7.9 dB with only 4 dB on-chip losses at the operating point.

Bidirectional grating coupler based optical modulator for low-loss integration and low-cost fiber packaging

We proposed and demonstrated a novel optical modulator based on a bidirectional grating coupler designed for perfectly vertical fiber coupling. The grating functions as the fiber coupler and 3-dB splitter. To observe the interference, an arm difference of 30μm is introduced. As a result of the high coupling efficiency and near perfect split ratio of the grating coupler, this device exhibits a low on-chip insertion loss of 5.4dB (coupling loss included) and high on-off extinction ratio more than 20dB. The modulation efficiency is estimated to be within 3-3.84V•cm. In order to investigate the fiber misalignment tolerance of this modulator, misalignment influence of the static characteristics is analyzed. 10Gb/s Data transmission experiments of this device are performed with different fiber launch positions. The energy efficiency is estimated to be 8.1pJ/bit.

High-speed, low-loss silicon Mach-Zehnder modulators with doping optimization

We demonstrate a high-speed silicon Mach-Zehnder modulator (MZM) with low insertion loss, based on the carrier depletion effect in a lateral PN junction. A 1.9 dB on-chip insertion loss and a VπLπ < 2 V·cm were achieved in an MZM with a 750 μm-long phase shifter by properly choosing the doping concentration and precisely locating the junction. High-speed modulations up to 45-60 Gbit/s have been demonstrated with an additional 1.6 dB optical loss, indicating a total insertion loss of 3.5 dB. A high extinction ratio of 7.5 dB was also realized at the bit rate of 50 Gbit/s with an acceptable insertion loss of 6.5 dB.

High-contrast 40 Gb/s operation of a 500 μm long silicon carrier-depletion slow wave modulator

In this Letter, we demonstrate a highly efficient, compact, high-contrast and low-loss silicon slow wave modulator based on a traveling-wave Mach-Zehnder interferometer with two 500 μm long slow wave phase shifters. 40  Gb/s operation with 6.6 dB extinction ratio at quadrature and with an on-chip insertion loss of only 6 dB is shown. These results confirm the benefits of slow light as a means to enhance the performance of silicon modulators based on the plasma dispersion effect.

Switching energy limits of waveguide-coupled graphene-on-graphene optical modulators

The fundamental switching energy limitations for waveguide coupled graphene-on-graphene optical modulators are described. The minimum energy is calculated under the constraints of fixed insertion loss and extinction ratio. Analytical relations for the switching energy both for realistic structures and in the quantum capacitance limit are derived and compared with numerical simulations. The results show that sub-femtojoule per bit switching energies and peak-to-peak voltages less than 0.1 V are achievable in graphene-on-graphene optical modulators using the constraint of 3 dB extinction ratio and 3 dB insertion loss. The quantum-capacitance limited switching energy for a single TE-mode modulator geometry is found to be < 0.5 fJ/bit at λ = 1.55 μm, and the dependences of the minimum energy on the waveguide geometry, wavelength, and graphene location are investigated. The low switching energy is a result of the very strong optical absorption in graphene, and the extremely-small operating voltages needed as the device approaches the quantum capacitance regime.

Performance tradeoff between lateral and interdigitated doping patterns for high speed carrier-depletion based silicon modulators

Carrier-depletion based silicon modulators with lateral and interdigitated PN junctions are compared systematically on the same fabrication platform. The interdigitated diode is shown to outperform the lateral diode in achieving a low VπLπ of 0.62 V∙cm with comparable propagation loss at the expense of a higher depletion capacitance. The low VπLπ of the interdigitated PN junction is employed to demonstrate 10 Gbit/s modulation with 7.5 dB extinction ration from a 500 µm long device whose static insertion loss is 2.8 dB. In addition, up to 40 Gbit/s modulation is demonstrated for a 3 mm long device comprising a lateral diode and a co-designed traveling wave electrode.

40 Gbit/s low-loss silicon optical modulator based on a pipin diode

40 Gbit/s low-loss silicon optical modulators are demonstrated. The devices are based on the carrier depletion effect in a pipin diode to generate a good compromise between high efficiency, speed and low optical loss. The diode is embedded in a Mach-Zehnder interferometer, and a self-aligned fabrication process was used to obtain precise localization of the active p-doped region in the middle of the waveguide. Using a 4.7 mm (resp. 0.95 mm) long phase shifter, the modulator exhibits an extinction ratio of 6.6 dB (resp. 3.2 dB), simultaneously with an optical loss of 6 dB (resp. 4.5 dB) at the same operating point.

High-speed low-voltage single-drive push-pull silicon Mach-Zehnder modulators

We demonstrate a single-drive push-pull silicon Mach-Zehnder modulator (MZM) with a π-phase-shift voltage of 3.1 V and speed up to 30 Gb/s. The on-chip insertion loss is 9 dB due to the use of a 6 mm-long phase shifter. Higher switching speed up to 40-50 Gb/s is also demonstrated in devices with shorter phase shifters which require higher drive voltages but have lower insertion losses.

Low-voltage, high-extinction-ratio, Mach-Zehnder silicon optical modulator for CMOS-compatible integration

We demonstrate a carrier-depletion Mach-Zehnder silicon optical modulator, which is compatible with CMOS fabrication process and works well at a low driving voltage. This is achieved by the optimization of the coplanar waveguide electrode to reduce the electrical signal transmission loss. At the same time, the velocity and impedance matching are both considered. The 12.5 Gbit/s data transmission experiment of the fabricated device with a 2-mm-long phase shifter is performed. The driving voltages with the swing amplitudes of 1 V and 2 V and the reverse bias voltages of 0.5 V and 0.8 V are applied to the device, respectively. The corresponding extinction ratios are 7.67 and 12.79 dB.

25 Gbit/s silicon microring modulator based on misalignment-tolerant interleaved PN junctions

A high-speed depletion-mode silicon-based microring modulator with interleaved PN junctions optimized for high modulation efficiency and large alignment tolerance is demonstrated. It is fabricated using standard 0.18 μm complementary metal-oxide-semiconductor processes and provides low V(π)L(π)s of 0.68 V·cm to 1.64 V·cm with a moderate doping concentration of 2 × 10(17) cm(-3). The measured modulation efficiency decreases by only 12.4% under ± 150 nm alignment errors. 25 Gbit/s non-return-zero modulation with a 4.5 dB extinction ratio is experimentally realized at a peak-to-peak driving voltage of 2 V, demonstrating the excellent performance of the novel doping profile.

Low-voltage high-performance silicon photonic devices and photonic integrated circuits operating up to 30 Gb/s

We present high performance silicon photonic circuits (PICs) defined for off-chip or on-chip photonic interconnects, where PN depletion Mach-Zehnder modulators and evanescent-coupled waveguide Ge-on-Si photodetectors were monolithically integrated on an SOI wafer with CMOS-compatible process. The fabricated silicon PIC(off-chip) for off-chip optical interconnects showed operation up to 30 Gb/s. Under differential drive of low-voltage 1.2 V(pp), the integrated 1 mm-phase-shifter modulator in the PIC(off-chip) demonstrated an extinction ratio (ER) of 10.5dB for 12.5 Gb/s, an ER of 9.1dB for 20 Gb/s, and an ER of 7.2 dB for 30 Gb/s operation, without adoption of travelling-wave electrodes. The device showed the modulation efficiency of V(π)L(π) ~1.59 Vcm, and the phase-shifter loss of 3.2 dB/mm for maximum optical transmission. The Ge photodetector, which allows simpler integration process based on reduced pressure chemical vapor deposition exhibited operation over 30 Gb/s with a low dark current of 700 nA at -1V. The fabricated silicon PIC(intra-chip) for on-chip (intra-chip) photonic interconnects, where the monolithically integrated modulator and Ge photodetector were connected by a silicon waveguide on the same chip, showed on-chip data transmissions up to 20 Gb/s, indicating potential application in future silicon on-chip optical network. We also report the performance of the hybrid silicon electronic-photonic IC (EPIC), where a PIC(intra-chip) chip and 0.13μm CMOS interface IC chips were hybrid-integrated.

Ten Gbit/s ring resonator silicon modulator based on interdigitated PN junctions

10 Gbit/s silicon modulator based on carrier depletion in interdigitated PN junctions is experimentally demonstrated. The phase-shifter is integrated in a ring resonator, and high extinction ratio larger than 10 dB is obtained in both TE and TM polarizations. VπLπ of about 2.5 V × cm and optical loss lower than 1 dB are estimated. 10 Gbit/s data transmission is demonstrated with an extinction ratio of 4 dB.