Propagation Loss Of Optical Waveguides Research Articles

Monolithic thin film lithium niobate electro-optic modulator with over 110 GHz bandwidth

High-performance thin film lithium niobate (LN) electro-optic modulators with low cost are in demand. Based on photolithography and wet etching, we experimentally demonstrate a thin film LN Mach–Zehnder modulator with a 3 dB bandwidth exceeding 110 GHz, which shows the potential of boosting the throughput and reducing cost. The fabricated modulator also exhibits a comparable low half-wave voltage-length product of ∼2.37 V·cm, a high extinction ratio of >23 dB, and the propagation loss of optical waveguides of ∼0.2 dB/cm. Besides, six-level pulse amplitude modulation up to 250 Gb/s is successfully achieved.

Synthesis of polyurethane-imids and application in surface plasmon polaritons waveguide

The crosslinkable electro-optic (EO) polymers polyurethane-imides (PUI) were designed and synthesized with monomers azo chromophore, phenyl diisocyanate and aromatic dianhydrides. Molecular structure characteristics for the polymers were evidenced by nuclear magnetic resonance (1HNMR) and fourier transform infrared (FTIR) spectroscopy. PUI as cladding, the strip long-range surface plasmon polaritons (LRSPPs) waveguides were designed and fabricated. The LRSPPs waveguiding along 18-nm-thin and 8-µm-wide gold stripes buried in EO PUI polymers were characterized at the light wavelength of 1310 nm and 1550 nm. The results indicated that the PUI can be used as preparation surface plasmon polaritons EO polymer optical waveguide materials, due to the merits of crosslinkable property, thermal stability, good film-forming ability, high processability and low optical waveguide propagation loss in near-infrared wave band.

Loss reduction of silicon-on-insulator waveguides for deep mid-infrared applications.

We report that propagation loss of optical waveguides based on a silicon-on-insulator (SOI) material platform can be greatly reduced. Our simulations show that the loss, including SiO2 absorption and substrate leakage, but no scattering loss, is 0.024 and 0.53dB/cm in the deep mid-infrared at 4.8 and 7.1μm wavelengths, where the material absorption in SiO2 is 100 and 1000dB/cm, respectively. The loss becomes negligible, compared to scattering loss in Si waveguides. This is enabled by using the TE10 mode in a pedestal waveguide. We also show that the TE10 mode can be excited in the proposed waveguide by the fundamental mode with a coupling efficiency of >94%. Low propagation loss, high coupling efficiency, and fabrication-friendly design would make it promising for practical use of SOI devices in the deep mid-infrared.

Large-Scale Silicone-Rubber-Based Optical Interconnect Packaged With FR4

Polydimethylsiloxane (PDMS)-based large-scale electrical-optical circuit boards (EOCBs) have been developed based on a combination of a large-scale PDMS waveguide fabrication technique and a process for efficient interfacial bonding between PDMS optical layers and standard FR4 (fiberglass-reinforced epoxy and grade 4 on flame retardance) printed circuit board materials using a specially developed surface adhesion promoter (SAP). The main mechanism of forming a good bonding between PDMS and FR4 has been identified. The optical properties of the PDMS waveguide layer remained unchanged by the addition of the SAP. According to the defined test procedures from the Institute of Printed Circuits, the International Electro Technical Commission, and Telcordia, the environmental stability of packaged EOCBs has been tested with the result that they exhibited excellent mechanical, optical, and thermal stabilities. The mechanical stability limit of the tested EOCBs is determined only by the intrinsic mechanical stability of the used PDMS materials. The optical waveguide propagation loss at 850 nm is less than 0.1 dB/cm after surviving from the defined environmental test procedures.

Polysiloxane based flexible electrical–optical-circuits-board

In the paper, a packaging technique of polysiloxane based flexible electrical–optical-circuits-board (EOCB) with Kapton (Dupont) foils was developed and introduced. The main mechanism of forming a good bonding between polysiloxane and Kapton foil was identified and verified. The optical and mechanical properties of the polysiloxane waveguide layer remained unchanged before and after packaging. According to the defined procedures, the environmental stability of packaged EOCBs has been tested with the result that they exhibited excellent mechanical, optical, and thermal stabilities. The mechanical stability limit of the tested EOCBs is determined only by the intrinsic mechanical stability of the used polysiloxane materials. The optical waveguide propagation loss at 850 nm is less than 0.1 dB/cm after surviving from the defined environmental test procedures.

Cost-effective waveguide integration method for large-scale electrical-optical-circuit-board production

Based on KMnO 4 wet etching technology, a low-cost waveguide integration technique of polydimethysiloxane (PDMS) based electrical-optical-circuit-board (EOCB) with FR4 substrates was developed, which is quite suitable for large-scale EOCB production. The optical and mechanical properties of the PDMS waveguide layer remained unchanged before and after waveguide integration. The mechanical stability limit of the tested EOCBs is determined only by the intrinsic mechanical stability of the used PDMS materials. The optical waveguide propagation loss at 850 nm is less than 0.1 dB/cm after surviving the defined environmental test procedures.

Optical waveguide propagation loss measurement using multiple reflections method

Optical waveguide propagation loss measurement method based on optical multiple reflections detection is presented in this paper. By using a precision reflectometer, uncertain influence on waveguide propagation loss measurement caused by fiber-waveguide coupling can be eliminated effectively and the waveguide net propagation loss can be measured accurately. To demonstrate this, the propagation loss of a Silicon-on-Insulator (SOI) rib waveguide fabricated by RIE is measured with the obtained value being 4.3dB/cm. This method provides a non-destructive means for evaluating waveguide propagation loss.

Propagation loss of optical waveguides prepared by cupper-alkali ion-exchange method

Propagation loss of optical waveguides prepared by cupper-alkali ion-exchange method

Comparison of three transmission methods for integrated optical waveguide propagation loss measurement

Three techniques for the measurement of propagation losses of single mode integrated optical waveguides are compared. The insertion loss measurement technique and the backcoupling method are suitable for the measurement of attenuation values alpha L>or=1. The resonator techniques give small relative mean errors of the attenuation only for high finesse resonators, which can, in principle, be realized by a waveguide Fabry-Perot resonator with high reflecting endfaces. A more convenient solution, however, is an additional ring resonator on the integrated optical chip.

Novel loss measurement technique for optical waveguides by imaging of scattered light

A novel technique is presented measuring propagation losses in optical waveguides by imaging the scattered intensity on a video camera. This technique requires no special sample preparation and is independent of the light coupling efficiency to the waveguide.

Losses in optical waveguide formed by silver-sodium ion exchange

Propagation losses of optical waveguides formed by ion exchange from molten salts of silver nitrate are discussed. The refractive index in pyrex glass substrates is shown to obey an exponential profile and the resultant mode functions are also examined for the graded-index surface waveguide in order to understand the mechanism of a scattering loss. The attenuation of the sample waveguides is found to range from 2.0 to 2.5 dB/cm for TE 0 mode excitation and to be decreasing with increasing both the mode number of the guided beam and the waveguide thickness that is proportional to a square root of diffusion time. These results indicate that the predominant loss origin is silver ion concentration diffused in the glass.

Single-crystal Sr2Nb2O7 film optical waveguide deposited by rf sputtering

A new optical waveguide of a single-crystal Sr2Nb2O7 film grown onto a b-plate Sr2Ta2O7 substrate by rf sputtering is reported. Waveguide propagation loss was 7.6 dB/cm for the TE0 mode at 6328 Å. An increased oxygen concentration in the sputtering gas is effective in lowering the optical waveguide propagation loss.