Query: mzm

title: Real Time 28 Gb/s NRZ over 80 km SSMF in C Band using Analog Electronic Precompensation
abstract: We demonstrate real time C band transmission of direct detected 28Gb/s NRZ/OOK over 80km SSMF using a Dual Drive MZM and custom designed SiGe BiCMOS 5 tap analog FIR filters to compensate chromatic dispersion without digital signal processing.

title: Channelized photonic assisted deramp receiver with an extended detection distance along the range direction for LFM CW radars.
abstract: A novel photonic assisted deramp receiver extends detection distance along range direction of linearly frequency modulated continuous wave (LFM CW) radars is proposed. A dual polarization quadrature phase shift keying (DP QPSK) modulator is used to modulate an optical frequency comb (OFC) to generate orthogonally polarized optical signals. Then the orthogonally polarized optical signals are coherently detected with an optical local oscillator (OLO) which is generated by modulating the other OFC with the RF reference signal on a null biased Mach Zehnder modulator (MZM) At the output of each detection unit, beating results can be recovered using a digital signal processing algorithm. By stitching the beating results of several paralleled detection units, the deramp signal corresponded to an extended range distance can be recovered. The proposed technique is experimentally evaluated through both simulated echoes and real echoes of two static trihedral corner reflectors (TCRs) distributed along range direction.

title: Mesoporous Zeolitic Materials (MZMs) Derived From Zeolite Y Using a Microwave Method for Catalysis
abstract: Mesostructured zeolitic materials (MZMs) with relatively high acidity in comparison with the mesoporous siliceous MCM 41 were prepared via an efficient, mild, and simple post synthetic treatment of Y zeolite facilitated by microwave irradiation, i.e. microwave assisted chelation (MWAC) The disordered mesoporous aluminosilicates materials (DMASs) of MZM were created from Y zeolite in the absence of using mesoscale templates. The prepared DMASs showed the good mesoporous features with the mesopore area and volume of ~260 m2 g 1 and ~0.37 cm3 g 1, respectively, and with the mesopore sizes distributed in a range of 2 10 nm. MZMs possess a total acidity of about 0.6 mmol g 1 and exhibited comparatively superior catalytic activity to the parent Y zeolite and MCM 41 in the vapor phase catalytic dealkylation of 1,3,5 triisopropylbenzene (TiPBz) and liquid phase catalytic aldol condensation of benzaldehyde with 1 heptanal. Although the yield loss was inevitable for preparing MZMs using the MWAC method, the preliminary economic analysis of the preparation cost of MZMs showed the promise. Additionally, a comprehensive comparison of the state of the art mesoporous materials concerning their sustainable aspects was made, showing that MZMs are promising mesoporous materials for further development and functionalization for catalysis.

title: A 50 Gb/s PAM4 Si Photonic Transmitter With Digital Assisted Distributed Driver and Integrated CDR in 40 nm CMOS
abstract: A 50 Gb/s four level pulse amplitude modulation (PAM4) silicon photonic transmitter is presented, which is composed of a 40 nm bulk CMOS driver hybrid integrated with a 180 nm silicon on insulator (SOI) CMOS Mach Zehnder modulator (MZM) To recover and demodulate 50 Gb/s PAM4 data into dual 25 Gb/s nonreturn to zero (NRZ) streams for the co designed MZM digital analog converter (DAC) a reference less clock and data recovery (CDR) is integrated, and to achieve high swing and high speed, the driver is made in a distributed amplifier (DA) employing push pull cells that are grouped in three segments. A digital assisted distributed driver (DADD) that replaces the input T line by segmented 2:1 multiplexers and buffers is, thus, proposed. Precise time gating in each segment allows for velocity match in both the DA and optical DAC, as well as the in segment pre emphasis without power hungry analog delay stages. Measurement results show that the driver and CDR achieve 4 VPP differential swing, 1.19 ps rms jitter, and 1.34 W power consumption at 50 Gb/s. An optical transmitter is demonstrated by wire bonding the driver to the MZM DAC, achieving 50 Gb/s PAM4 output with 6.35 ps rms jitter and improved linearity.

title: High linearity silicon modulator capable of actively compensating input distortion.
abstract: In this Letter, we demonstrate an ultra high linearity silicon carrier depletion based modulator by integrating a dual parallel Mach Zehnder modulator (DP MZM) with a 1x2 thermo optical switch. The operation principle is to manipulate power distributions of RF and optical signals among the two sub MZMs, so their third order nonlinearities can cancel each other. Spurious free dynamic ranges (SFDRs) for the third order intermodulation distortion (IMD3) are measured to be 123/120dBHz6/7 at 1/10 GHz, which represents a record high linearity achieved with silicon based modulators. As a contrast, SFDRs of a reference single MZM are 113/108dBHz4/5 at the same frequencies. Furthermore, we first demonstrate that this device is able to actively compensate nonlinear distortions of RF driving signals in the optical domain. Carrier to distortion ratios (CDRs) of deliberately distorted two tone signals are improved from 40/50 dB to 45/72 dB after the modulation.

title: Electro Optic Frequency Response Shaping in High Speed Mach Zehnder Modulators
abstract: We demonstrate a simple technique to shape the electro optic frequency response of high speed TW MZMs. C band transmission of 56Gb/s NRZ over 3km SSMF shows 5dB power penalty improvement at KP4 FEC between a standard and shaped MZM design.

title: Study on the Compensation of Silicon Photonics Based Modulators in DCI Applications
abstract: For next generation high speed optical coherent systems, digital pre emphasis filters are essential as they can pre compensate for the transmitter frequency response and mitigate receiver noise enhancement. However, the downside of using full pre emphasis to completely pre compensate for the low bandwidth transmitter is that it increases the signal peak to average power ratio (PAPR) thus posing a higher effective number of bits (ENoB) requirement for the digital to analog converter (DAC) and increases optical modulation loss. In this paper, we study the impact of partial pre emphasis filters on signal PAPR and show how partial pre emphasis reduces DAC ENoB requirements and MZM modulation loss. Our proposed scheme reduced the DAC ENoB requirement from 5 to 4.5 bits at the same implementation SNR. This enables a lower optical module power through the reduction of DAC and driver amplifier (DA) power. The experimental results, for single pol case for a partial pre emphasis filter, showed that the system bandwidth can be extended from 10GHz to 20GHz and tolerate a 6dB loss for a 0.4dBQ penalty factor, and a 0.8dB PAPR reduction.

title: Photonic based reconfigurable microwave frequency divider using two cascaded dual parallel Mach Zehnder modulators.
abstract: A photonic based reconfigurable microwave frequency divider using two cascaded dual parallel Mach Zehnder modulators (DP MZMs) is proposed. The first DP MZM is driven by the input microwave signal, whereas the second DP MZM is incorporated in an optoelectronic oscillator (OEO) loop and driven by the feedback signal. By properly setting the working conditions of the two DP MZMs, the frequency of the input microwave signal is divided and the frequency divided signal will oscillate in the OEO loop, with a tunable frequency division factor determined by the bias conditions of the DP MZMs. An experiment is performed. The reconfigurable microwave frequency divider is demonstrated with a frequency division factor of 1.5, 2.5, 2, or 3, and the phase noise of the frequency divided signals is also evaluated, which has an improvement of 3.22, 7.60, 5.80, or 9.49 dB at 10 kHz frequency offset, respectively, compared with that of the input microwave signals.

title: High Resolution $X$ Band Frequency Synthesizer Using SILPLL Optoelectronic Oscillators
abstract: Optoelectronic oscillators (OEOs) with their demonstrated low phase noise are popular due to the increasing demand of very clean local oscillator and clock signal sources. A forced technique of self injection locked and phase locked loop (SILPLL) reduces phase noise and suppresses side mode observed in long fiber delay of the standard OEO. A frequency synthesizer working at <inline formula> <tex math notation="LaTeX"$X$ /tex math>/inline formula> band is developed using an electrically coarse tuned YIG filter cascaded with an optical wavelength fine tuned dispersive optical transversal filter by tuning the oscillation frequency of the synthesized OEO frequency, as a replacement for fixed frequency narrowband filter using high <inline formula> <tex math notation="LaTeX"$Q$ /tex math>/inline formula> aluminum cavities. A close to carrier phase noise of 115 dBc/Hz at 1 kHz is reported by the <inline formula> <tex math notation="LaTeX"$V_{\pi /2} /tex math>/inline formula> operation of a Mach Zehnder modulator (MZM) over 8 12 GHz with a frequency tuning step as small as 2.6 kHz. Phase noise introduced by a photodetector is also explored at a very close to carrier frequency. It shows 10 dB phase noise degradation at PD reverse bias voltage of 3 V compared with 6 V at close to the <inline formula> <tex math notation="LaTeX"$V_{\pi /tex math>/inline formula> operation of an MZM. A 19 in rack mount frequency synthesizer system is also realized at <inline formula> <tex math notation="LaTeX"$X$ /tex math>/inline formula> band with a demonstrated long term (up to 60 min) frequency drift stability of 3 kHz over whole <inline formula> <tex math notation="LaTeX"$X$ /tex math>/inline formula> band working frequencies.

title: 23 dB average isolation using a silicon photonic Mach Zehnder modulator.
abstract: We demonstrate an optical time gate isolator entirely fabricated on the silicon on insulator (SOI) platform based on a conventional traveling wave Mach Zehnder modulator (TW MZM) design. The device achieves 18.2 dB (22.7 dB) time averaged isolation when driven with 2.0 Vpp (7.1 Vpp) differential clock signals at 6.8 GHz and biased at null. Under these conditions, the isolator blocks backward light at all time regardless of driver amplitude, but produces periodic modulation in the forward direction. Moreover, we embed our isolator in a digital communication link and measure a signal to noise ratio (SNR) penalty of only 0.5 dB due to the isolator at 13.6 Gbaud PAM 4 data rate. Our device can be integrated in larger circuits to protect laser sources or mitigate interference.