Plasmonic electro-optic modulator design using a resonant metal grating

A plasmonic electro-optic modulator design using an evanescently coupled resonant metal grating is numerically studied in this Letter. Owing to excitation and propagation of long-range surface plasmons between the metal grating nanowires, a deep and narrow reflection dip can be obtained. Improved modulation performance is achieved through decreased damping from large dielectric gaps between the grating nanowires. An optimized electro-optic modulator design with lower insertion loss and low operating voltage is presented.     

Ultrabroad-bandwidth electro-optic modulator based on a cascaded Bragg grating

It is shown that the bandwidth of a traveling-wave electro-optical modulator can be greatly increased by matching of the group velocities of the optical and rf waves in the waveguides with cascaded Bragg gratings. A LiNbO>(3) Mach-Zehnder modulator with 1-V half-wave voltage and a bandwidth in excess of 100 GHz is proposed and its performance evaluated.     

基于电光聚合物的表面等离激元调制器

基于电光聚合物,提出了一种结构简单,尺寸小,效率高的表面等离激元(SPP)调制器.该调制器采用M-Z干涉仪结构的金属波导,金属周围是均匀极化后的电光聚合物,通过在金属波导两臂间加电压对聚合物折射率进行调制,折射率调制再通过M-Z干涉仪结构转化为对金属波导中SPP强度的调制. 通过求解金属波导附近的电场分布,并结合SPP场分布的特点,在理论上说明了这种结构可以通过外加电压有效地调制金属波导输出端SPP的强度,调制所需的半波电压约为2.8V. 关键词： 表面等离激元 电光调制 电光聚合物     

GaAs travelling-wave optical modulator using a coplanar slow-wave electrode with periodic overlays

A coplanar slow-wave electrode with periodic cross-tie overlays has been used to satisfy the essential phase velocity matching between the modulation and optical waves for wideband travelling-wave optical modulators. For an optimized modulator of 4 mm length at 1.3 m light wavelength, the calculated halfwave modulation voltage (23 V) is slightly higher than that (20 V) of conventional coplanar modulators but the 3 dB bandwidth (100 GHz) is much wider than the bandwidth limit (30 GHz) of walkoff-limited conventional coplanar modulators. The measured effective index (4.61) of the modulation wave is much higher than that (2.65) of conventional coplanar electrodes and agrees very well with the calculated one (4.25).     

掺Er光纤飞秒激光器中电光晶体对激光器参数的影响

由于受增益介质上能级寿命的影响,掺Er光纤光梳的梳齿线宽一般在百kHz量级.为了实现光梳梳齿线宽的压窄,一种有效的方法是在激光器中增加快速响应的电光晶体,使光纤光梳的伺服锁定带宽提高到百kHz以上,为光纤光梳的快速伺服锁定提供反馈机构.这其中,高品质的飞秒激光器是核心.基于此,本文主要研究了掺Er光纤飞秒激光器中电光晶...     

一种基于导模共振的电光调制器研究

实验研究了基于导模共振的反射型电光调制器采用的棱镜耦合方式,在棱镜上面镀有4层膜,依次为银膜下电极-极化聚合物-缓冲层-金膜上电极。对这种衰减全反射（ATR）型的聚合物波导电光调制器进行了视频调制实验,采用静态偏置电压稳定模式同步角方法,结合对入射激光束进行监测,解决了视频调制中激光器噪声对模拟信号调制影响的问题,提高了工作稳定性。实验结果表明：该电光调制器具有良好的线性和较高的灵敏度。     

Ultracompact electro-optic phase modulator based on III-V-on-silicon microdisk resonator

A novel ultracompact electro-optic phase modulator based on a single 9 μm-diameter III-V microdisk resonator heterogeneously integrated on and coupled to a nanophotonic waveguide is presented. Modulation is enabled by effective index modification through carrier injection. Proof-of-concept implementation involving binary phase shift keying modulation format is assembled. A power imbalance of ～0.6 dB between both symbols and a modulation rate up to 1.8 Gbps are demonstrated without using any special driving technique.     

Photonic ultrawideband monocycle pulse generation using a single electro-optic modulator

A compact approach to photonic-assisted ultrawideband (UWB) monocycle pulse generation is proposed and experimentally demonstrated based on the wavelength dependence of the half-wave voltage of a Mach-Zehnder modulator (MZM). By employing a single MZM with dual-wavelength injection at around 1310 and 1550 nm, a pair of polarity-reversed monocycle pulses with the full width at half-maximum of about 80 ps and the fractional bandwidth of greater than 160% can be generated. The experiment results agree well with the theoretical prediction. The simple setup and the convenience to control the monocycle pulse polarity are favorable for future applications.     

Carrier-injection-based electro-optic modulator on silicon-on-insulator with a heterogeneously integrated III-V microdisk cavity

A compact electro-optic modulator on silicon-on-insulator is presented. The structure consists of a III-V microdisk cavity heterogeneously integrated on a silicon-on-insulator wire waveguide. By modulating the loss of the active layer included in the cavity through carrier injection, the power of the transmitted light at the resonant wavelength is modulated; approximately 10 dB extinction ratio and 2.73 Gbps dynamic operation are demonstrated without using any special driving techniques.     

Design of a silicon-based field-effect electro-optic modulator with enhanced light-charge interaction

A new design for an all-silicon field-effect optical modulator in a ring resonator geometry is proposed and modeled by means of finite-element method simulations. It is shown that the optimal relative placement of the ultrathin field-effect-generated charge layers and the optical mode in the strong-confinement waveguides leads to more than an order-of-magnitude enhancement in the light-charge interaction compared with the recent predictions in the literature. We show that such an enhancement could provide optical modulation with a >7 dB extinction-ratio using a voltage swing of only 2 V, thus making our design compatible with complementary metal-oxide semiconductor technology.     

TBOR-shaped electro-optic modulator with dual output based on double-layer graphene

We proposed an electro-optic modulator with two-bus one-ring (TBOR) structure to improve the extinction ratio and reduce insert loss. It has a dual output compared with one-bus one-ring structure. In addition, double-layer graphene makes it possible for the modulation in the visible to mid-infrared wavelength range. It shows that this new electro-optic modulator can present two switching states well with low insertion loss, high absorption and high extinction ratio. At $\lambda =1550\text{ nm}$, when the switching states are based on the chemical potential, ${\mu }_{\mathrm{c}}=0.38\text{ eV}$ and ${\mu }_{\mathrm{c}}=0.4\text{ eV}$, the insertion losses of both output ports are less than 2 dB, the absorption of the output port coupled via a micro-ring reaches 45 dB and the extinction ratio reaches 14 dB. When the refractive index of the dielectric material is 4.2, the applied voltage will be less than 1.2 V, thus can be used in low-voltage CMOS technology.     

A novel super-broadband travelling-wave modulator with nonperiodic domain inversions and ridge structure

In order to obtain large broadband, a novel travelling-wave modulator with nonperiodic domain inversions and ridge structure is proposed. The composite structure is designed to achieve velocity matching between the optical wave and the microwave, to get a 50Ωcharacteristic impedance and to reduce the loss of the microwave electrodes with finite element method (FEM). The calculation results show that the frequency response of the new device is flat up to 350 GHz with interaction length of 1 cm, characteristic impedance of 49Ω, and microwave refractive index of 2.5.     

Low-V(pi) electro-optic modulator with a high-microbeta chromophore and a constant-bias field

A low half-wave voltage V(pi) of 1.57 V was obtained with a 2-cm-long birefringent polymer waveguide modulator at a wavelength of 1.3 microm by use of a modulator design with a constant-bias electric field and a high-microbeta chromophore. The design allows the maximum achievable electro-optic coefficient of the material to be utilized. This electro-optic coefficient can be more than twice as high as the residue value that is used by conventional modulator designs, after fast partial relaxation following poling.     

基于长周期光栅的有机聚合物高速电光调制器

结合长周期光栅的特性和有机聚合物的优点,首次提出了一种新型的基于长周期光栅的有机聚合物高速电光调制器结构。应用多层光波导理论,分析计算了聚合物折射系数变化与长周期光栅谐振波长的关系。在此基础上进行了模拟实验,结果表明理论分析与实验基本一致。     

A note on the nonlinear distortion performance of the Mach-Zehnder electro-optic modulator

A generalised large voltage analysis is presented for the Mach-Zehnder modulator and closed-form expressions are derived for the output harmonics and intermodulation products. Results obtained previously, for small voltages, are derived as a special case.     

45 kHz,2 kV电光调制电路的设计与应用

根据差分相移量子密钥分发实验对高速电光调制电路的需求,利用固体开关技术和变压器隔离技术,设计出了重复频率为45 kHz、输出脉冲电压达到2 kV的电光调制电路,该电光调制电路由两部分组成,正负1 kV高压脉冲产生电路,其中正1 kV高压脉冲的上升沿为50.44 ns,下降沿为44.6 ns,负1 kV高压脉冲下降沿为52.29 ns,上升沿为50.44 ns。普克尔盒调制电路与光路进行联调,光路的消光比达到23 dB,完全满足了消光比为20 dB的实验需求。     

45kHz,2kV电光调制电路的设计与应用

根据差分相移量子密钥分发实验对高速电光调制电路的需求,利用固体开关技术和变压器隔离技术,设计出了重复频率为45kHz、输出脉冲电压达到2kV的电光调制电路,该电光调制电路由两部分组成,正负1kV高压脉冲产生电路,其中正1kV高压脉冲的上升沿为50.44ns,下降沿为44.6ns,负1kV高压脉冲下降沿为52.29ns,上升沿为50.44ns。普克尔盒调制电路与光路进行联调,光路的消光比达到23dB,完全满足了消光比为20dB的实验需求。     

Fabrication and characteristics of thermal crosslinking polyurethane integrated double-channel electro-optic modulator

The fabrication and characteristics of a new type of polymeric electro-optic modulator with double channels in attenuated total reflection (ATR) configuration, made of a thermally crosslinkable polyurethane, has been demonstrated in this paper. The fabrication procedure of proposed double-channel ATR modulator is extremely simple, it can be implemented by replacing a single electrode with two discrete electrodes in a single channel ATR modulator. Independent operation of both channels is demonstrated at a modulation speed of 500 MHz. The total measured insertion loss of the modulator is below 1.5 dB. There are no measurable cross talks due to the large horizontal separation of two channels and the small vertical separation of the electrode pair. A long-term thermal stability of the fabrication modulator at an elevated temperature, 100 °C, is obtained due to crosslinking polyurethane as the waveguide layer of the devices.     

Generation of frequency-chirped laser pulses by an electro-optic amplitude modulator

We propose a single electro-optic amplitude modulator to modulate both the intensity and the phase of the light of a diode laser to produce frequency-chirped light pulses in the nanosecond time range. The two-in-one property of the Mach–Zehnder type electro-optic amplitude modulator is used to create a specific device available for experiments with cooled atoms. The phase induced in each optical path of the Mach–Zehnder interferometer and the phase-to-intensity modulation ratio, the intrinsic chirp parameter of the device is determined by generating high order optical harmonics.