Silicon-based optoelectronic heterogeneous integration for optical interconnection

The performance of optical interconnection has improved dramatically in recent years.Silicon-based optoelectronic heterogeneous integration is the key enabler to achieve high performance optical interconnection,which not only provides the optical gain which is absent from native Si substrates and enables complete photonic functionalities on chip,but also improves the system performance through advanced heterogeneous integrated packaging.This paper reviews recent progress of silicon-based optoelectronic heterogeneous integration in high performance optical interconnection.The research status,development trend and application of ultra-low loss optical waveguides,high-speed detectors,high-speed modulators,lasers and 2D,2.5D,3D and monolithic integration are focused on.

Structured Illumination Chip Based on Integrated Optics

A compact structured illumination chip based on integrated optics is proposed and fabricated on a silicon-on- insulator platform. Based on the simulation of Caussian beam interference, we adopt a chirped diffraction grating to achieve a specific interference pattern. The experimental results match well with the simulations. The portability and flexibility of the structured illumination chip can be increased greatly through horizontal encapsulation. High levels of integration, compared with the conventional structured illumination approach, make this chip very compact, with a footprint of only around 1 mm2. The chip has no optical lenses and can be easily combined with a microfluidic system. These properties would make the chip very suitable for portable 3D scanner and compact super-resolution microscopy applications.

Large-capacity and low-loss integrated optical buffer

Trapping light in a photonic integrated circuit can findmany applications, such as optical storage, optical-packetswitching, optical sensing and microwave photonics. Althoughthere are many ways to implement an integrated opticalbuffer, such as the use of ring resonators, photonic crystals,Bragg gratings and spiral waveguides, it is still challenging torealize optical buffers with long storage time and low loss.Photonic integrated circuits with small size are of interest forimplementing optical buffers. In general, three materials systemsare employed to implement integrated optical buffers, silicon,silicon nitride and indium phosphide. However, it is hardto implement optical buffers with a storage time over tens ofnanoseconds due to the intrinsic high loss of these materials.

Design and simulation of a silicon-based hybrid integrated optical gyroscope system

By combining a silicon-based lithium niobate modulator and a silicon-based Si3N4resonator with silicon-based photonics technology,a highly systematic design of a hybrid integrated optical gyroscope with enhanced reciprocity sensitivity and a dual micro-ring structure is proposed for the first time in this paper.The relationship between the device's structural parameters and optical performance is also analyzed by constructing a complete simulation link,which provides a theoretical design reference to improve the system's sensitivity.When the wavelength is 1550 nm,the conversion frequency of the dual-ring optical path is 50 MHz,the coupling coefficient is 0.2,and the radius R is 1000μm,the quality factor of the silicon-based Si_(3)N_(4)resonator is 2.58×10^(5),which is 1.58 times that of the silicon-on-insulator resonator.Moreover,the effective number of times the light travels around the ring before leaving the micro-ring is 5.93,which is 1.62 times that of the silicon-on-insulator resonator.The work fits the gyro dynamic output diagram,and solves the problem of low sensitivity at low speed by setting the phase offset.This results provide a basis for the further optimization of design and chip processing of the integrated optical gyroscope.

Optical design and simulation of an integrated OCT and video rigid laryngoscope

An integrated optical coherence tomography(OCT)and video rigid laryngoscope have been designed to acquire surface and subsurface tissue images of larynx simultaneously.The dual-modality system that is based on a common-path design with components as few as possible effec-tively maintains the light transmittance without compromising the imaging quality.In this paper,the field of view(FOV)of the system can reach 70°by use of a gradient index(GRIN)lens as the relay element and a four-lens group as the distal objective,respectively.The simulation showed that the modulation transfer function(MTF)value in each FOV of the rigid video endoscope at 160 lp/mm is greater than 0.1 while the root mean square(RMS)radii of the OCT beam in the center and edge of the FOV are 14.948μm and 73.609μm,respectively.The resolutions of both OCT and video endoscope meet the requirement of clinical application.In addition,all the components of the system are spherical,therefore the system can be of low cost and easy to assemble.

Integrated system of traditional THz time-domain spectroscopy and asynchronous optical sampling

Terahertz time-domain spectroscopy(THz-TDS)system,as a new means of spectral analysis and detection,plays an increasingly pivotal role in basic scientific research.However,owing to the long scanning time of the traditional THz-TDS system and the complex control of the asynchronous optical scanning(ASOPS)system,which requires frequent calibration,we combine traditional THz-TDS and ASOPS systems to form a composite system and propose an all-fiber trigger signal generation method based on the time overlapping interference signal generated by the collinear motion of two laser pulses.Finally,the time-domain and frequency-domain spectra are obtained by using two independent systems in the integrated systems.It is found that the full width at half maximum(FWHM)of the time-domain spectra and the spectral width of the frequency-domain spectra are almost the same,but the sampling speed of the ASOPS system is significantly faster than that of the traditional THz-TDS system,which conduces to the study of the transient characteristics of substances.

Integrated Optics Acoustooptic Receiver

The recent advances on the research and the applications of the integrated optics acousto-optic spectrum analyzer(IOSA) are reviewed. The operating principle, architecture, characteristics and technology, and future development of the different receivers are described.

Fully On-Chip Integrated Photodetector Front-End Dedicated to Real-Time Portable Optical Brain Imaging

Optical brain imaging using functional near infra-red spectroscopy (fNIRS) offers a portable and noninvasive tool for monitoring of blood oxygenation. In this paper we have introduced a new miniaturized photodetector front-end on achip to be applied in a portable fNIRS system. It includes silicon avalanche photodiodes (SiAPD), Transimpedance amplifier (TIA) front-end and Quench-Reset circuitry to operate in both linear and Geiger modes. So it can be applied for both continuous-wave fNIRS (CW-fNIRS) and also single-photon counting. Proposed SiAPD exhibits high-avalanche gain (>100), low-breakdown voltage ( V) and high photon detection efficiency accompanying with low dark count rates. The proposed TIA front-end offer a low power consumption ( mW), high-transimpedance gain (up to 250 MV/A), tunable bandwidth (1 kHz - 1 GHz) and very low input and output noise (~few fA/√Hz and few μV/√Hz). The Geiger-mode photon counting front-end also exhibits a controllable hold-off and rest time with an ultra fast quench-reset time (few ns). This integrated system has been implemented using submicron (0.35 μm) standard CMOS technology.

Monolithically Integrated Laser Diode and Electroabsorption Modulator with Dual-Waveguide Spot-Size Converter Output

A 1.60μm laser diode and electroabsorption modulator monolithically integrated with a novel dual-waveguide spot-size converter output for low-loss coupling to a cleaved single-mode optical fiber are demonstrated.The devices emit in a single transverse and quasi single longitudinal mode with an SMSR of 25.6dB.These devices exhibit a 3dB modulation bandwidth of 15.0GHz,and modulator DC extinction ratios of 16.2dB.The output beam divergence angles of the spot-size converter in the horizontal and vertical directions are as small as 7.3°×18.0°,respectively,resulting in a 3.0dB coupling loss with a cleaved single-mode optical fiber.

1.55μm Laser Diode Monolithically Integrated with Spot-Size Converter Using Conventional Process

A novel 1 55μm laser diode with spot size converter is designed and fabricated using conventional photolithography and chemical wet etching process.For the laser diode,a ridge double core structure is employed.For the spot size converter,a buried ridge double core structure is incorporated.The laterally tapered active core is designed and optically combined with the thin and wide passive core to control the size of mode.The laser diode threshold current is measured to be 40mA together with high slop efficiency of 0 35W/A.The beam divergence angles in the horizontal and vertical directions are as small as 14 89°×18 18°,respectively,resulting in low coupling losses with a cleaved optical fiber (3dB loss).

An acupuncture meta-analysis for optic atrophy Seven randomized,controlled trials

OBJECTIVE： To evaluate the efficacy and safety of acupuncture for optic atrophy. DATA SOURCES： A computer-based online search was conducted in Medline （1966-2008）, Embase （1986-2008）, the Cochrane Library （up to 2008）, Chinese Biomedical Literature Database （1975-2008）, China National Knowledge Infrastructure （1994-2008）, VIP Database （1989-2008）, Wanfang Database （1980-2008） and the National Research Register for ongoing trials. DATA SELECTION： Randomized, controlled trials addressing acupuncture treatment for patients with optic atrophy were included in this review. Inclusion criteria evaluated all forms of acupuncture therapy, such as filiform needle, electro-acupuncture, laser-acupuncture, acupressure, and auricular-acupuncture. Comparisons between acupuncture therapy and no treatment （blank） or placebo or Chinese medicine or Western medicine, as well as between acupuncture as an adjuvant and other treatments, were included. Exclusion criteria included studies comparing different forms of acupuncture therapy, different manipulations of acupuncture, and different acupuncture prescriptions, as well as non-randomized, controlled trials and animal studies. The domain-based evaluation criteria recommended by the guidelines in Chapter 8 of the Cochrane Handbook for Systematic Reviews of Interventions 5.0.1 was used to assess quality of the included studies. According to the type of outcome index, measurement data as assessed by weighted mean difference or standardized mean difference and 95% confidence interval; numeration data was estimated by relative risk and 95% confidence interval. Heterogeneity was analyzed by Meta-analysis using RevMan 5.0 software. MAIN OUTCOME MEASURES： Improved visual acuity and visual field was sought between treatment and control groups in the included articles. RESULTS： Seven randomized, controlled trials were included after screening and application of inclusion and exclusion criteria. However, the studies were of low methodological quality and lacked comparisons between acupuncture and no treatment or placebo. Applying visual acuity as the outcome index, meta-analysis indicated： the effect of medicine combined with acupuncture was superior to the medicine alone （relative risk = 1.41, 95% confidence interval 1.14-1.70, P 〈 0.01 ）, the efficacy of acupuncture was better than medicine alone （relative risk =1.42, 95% confidence interval 1.14-1.77, P 〈 0.01 ）. Using visual field as the other outcome index, meta-analysis revealed： effectiveness of acupuncture or acupuncture in combination with medicine was superior to medicine alone （relative risk = 1.47, 95% confidence interval 1.27-1.69, P 〈 0.01 ）. The 7 included articles were incorporated in a sensitivity analysis, and the overall effect showed a significant difference （relative risk = 1.35, 95% confidence interval 1.16-1.56, P 〈 0.01）. Acupuncture was not associated with any adverse events in any of the studies. CONCLUSION： Acupuncture therapy was determined to be superior to medicine in terms of improved visual acuity and visual field. However, well-designed, randomized, controlled trials with adequate controls and scientific rigor are urgently needed.

Integrated model optocouplers

Utilizing hybrid integration model.the integrated model optocouplers have successfully developed.The design,fabrication and characteristic parameters of the devices are presented.

Chaos generation by a hybrid integrated chaotic semiconductor laser

We design a hybrid integrated chaotic semiconductor laser with short-cavity optical feedback.It can be assembled in a commercial butterfly shell with just three micro-lenses.One of them is coated by a transflective film to provide the optical feedback for chaos generation while insuring regular laser transmission.We prove the feasibility of the chaos generation in this compact structure and provide critical external parameters for the fabrication by theoretical simulations.Rather than the usual changeless internal parameters used in previous simulation research,we extract the real parameters of the chip by experiment.Moreover,the maps of the largest Lyapunov exponent with varying bias current and feedback intensity Kap demonstrate the dynamic characteristics under different external-cavity conditions.Each laser chip has its own optimal external cavity length(L)and feedback intensity(Kap)to generate chaos because of the different internal parameters.We have acquired two ranges of optimal parameters(L=4 mm,0.12〈Kap〈0.2 and L=5 mm,0.07〈Kap〈0.12)for two different chips.

S-type Er-Yb Co-doped Phosphate Glass Waveguide Amplifier Integrated with Cascaded Multilayer Medium Thin Film Filter

A new S-type of erbium-ytterbium co-doped phosphate glass waveguide amplifier integrated with cascaded multilayer medium thin film filter is proposed,this S-type geometry waveguide structure is used to achieve a long path in a compact chip,and obtained higher gain with lower Er-doped concentration. The cascaded multilayer medium thin film filter is utilized to achieve a broader flattening gain bandwidth.The intrinsical gain spectrum is obtained by solving rate and power propagation equations,the effect of transmittance spectrum of thin film filter on flattening gain is discussed.

Determination of optical properties of normal and adenomatous human colon tissues in vitro using integrating sphere techniques

AIM: The purpose of the present study is to compare the optical properties of normal human colon mucosa/submucosa and muscle layer/chorion, and adenomatous human colon mucosa/submucosa and muscle layer/chorion in vitro at 476.5, 488, 496.5, 514.5 and 532 nm. We believe these differences in optical properties should help differential diagnosis of human colon tissues by using optical methods.METHODS: In vitro optical properties were investigated for four kinds of tissues: normal human colon mucosa/submucosa and muscle layer/chorion, and adenomatous human colon mucosa/submucosa and muscle layer/chorion. Tissue samples were taken from 13 human colons (13 adenomatous, 13 normal). From the normal human colons a total of 26 tissue samples, with a mean thickness of 0.40 mm, were used (13 from mucosa/submucosa and 13 from muscle layer/chorion), and from the adenomatous human bladders a total of 26 tissue samples, with a mean thickness of 0.40 mm, were used (13 from mucosa/submucosa and 13 from muscle layer/chorion). The measurements were performed using a double-integratingsphere setup and the optical properties were assessed from these measurements using the adding-doubling method that was considered reliable.RESULTS: The results of measurement showed that there were significant differences in the absorption coefficients and scattering coefficients between normal and adenomatous human colon mucosa/submucosa at the same wavelength,and there were also significant differences in the two optical parameters between both colon muscle layer/chorion at the same wavelength. And there were large differences in the anisotropy factors between both colon mucosa/submucosa at the same wavelength, there were also large differences in the anisotropy factors between both colon muscle layer/chorion at the same wavelength.There were large differences in the value ranges of the absorption coefficients, scattering coefficients and anisotropy factors between both colon mucosa/submucosa,and there were also large differences in these value ranges between both colon muscle layer/chorion. There are the same orders of magnitude in the absorption coefficients for four kinds of colon tissues. The scattering coefficients of these tissues exceed the absorption coefficients by at least two orders of magnitude.CONCLUSION: There were large differences in the three optical parameters between normal and adenomatous human colon mucosa/submucosa at the same laser wavelength, and there were also large differences in these parameters between both colon muscle layer/chorion at the same laser wavelength. Large differences in optical parameters indicate that there were large differences in compositions and structures between both colon mucosa/submucosa, and between both colon muscle layer/chorion.Optical parameters for four kinds of colon tissues are wavelength dependent, and these differences would be useful and helpful in clinical applications of laser and tumors photodynamic therapy (PDT).

The 8×10 GHz Receiver Optical Subassembly Based on Silica Hybrid Integration Technology for Data Center Interconnection

An 8×10 GHz receiver optical sub-assembly （ROSA） consisting of an 8-channel arrayed waveguide grating （AWG） and an 8-channel PIN photodetector （PD） array is designed and fabricated based on silica hybrid integration technology. Multimode output waveguides in the silica AWG with 2% refractive index difference are used to obtain fiat-top spectra. The output waveguide facet is polished to 45° bevel to change the light propagation direction into the mesa-type PIN PD, which simplifies the packaging process. The experimentM results show that the single channel I dB bandwidth of AWG ranges from 2.12nm to 3.06nm, the ROSA responsivity ranges from 0.097 A/W to 0.158A/W, and the 3dB bandwidth is up to 11 GHz. It is promising to be applied in the eight-lane WDM transmission system in data center interconnection.

Bilateral Optical Nerve Atrophy Secondary to Lateral Occipital Lobe Infarction

Purpose:To report a phenomenon of optical nerve atrophy secondary to lateral occipital lobe infarction. Methods:Two successive patients with unilateral occipital lobe infarction who experienced bilateral optical nerve atrophy during the follow-up underwent cranial imaging, fundus photography, and campimetry. Results:Each patient was diagnosed with occipital lobe infarction by cranial MRI. During the follow-up, a bilateral optic atrophy was revealed,and campimetry showed a right homonymous hemianopia of both eyes with concomitant macular division. Conclusion:Bilateral optic atrophy was related to occipital lobe infarction, and a possible explanation for the atrophy was transneuronal degeneration caused by occipital lobe infarction.

HOW TO TREAT OPTIC ATROPHY WITH ACUPUNCTURE ?

Optic atrophy results mostly from affection by exopathic wind pathogen, insufficiency of Qi and Xue(blood) or hyperactivity of the liver-yang. We choose Qiuhou(EX-HN 7), Jingming(BL1 ), Taiyang(EX-HN 5 ) and Fengchi(GB 20) as the main acupoints and combine other auxiliary points according to different syndromes. For example, Hegu(LI 4) and Waiguan(TE 5 ) are supplemented for affection by exopathic wind pathogen, Qihai(CV 6), Zusanli(ST 36), Xuehai(SP 10) and Guang-ming(GB 37) for insufficiency of Qi and Xue, and Guanshu(BL 18), Baihui(GV 20), Taixi(KI 3),Sanyinjiao(SP 6) and Guangming(GB 37) for hyperactivity of the liveryang. When Qiuhou(EX-HN 7), Jingming(BL 1 ) and Fenchi(GB 20) punctured, the need1ing direction, angle and depth should be controlled very appropriate for achieving good therapeutic effect.

CLINICAL OBSERVATION ON TREATMENT OF 110 CASES OF OPTIC ATROPHY WITH ACUPUNCTURE

The author punctured Kuangshang (the medial one third of the supraorbitalmargin ), Jieli (midway between the occipital condyle and apex helix) and Yintang ((EX-HN3 ) asmain points to treat optic atrophy in 164 eyes of 110 patients. The results showed that 12 eyes (7.3% ) were cured, 71 eyes (43. 3 % ) remarkably effective, 39 eyes (23. 8 % ) improved and 42 eyes(25. 6 % ) ineffective, with the total effective rate 74. 4 %.

OBSERVATION ON THE THERAPEUTIC EFFECT OF ACUPUNCTURE ON OPTIC ATROPHY(48 CASES)

48 cases of optic atrophy were treated with acupuncture. Qiuhou (EX-HN 7), Jing-ming (BL 1), Ganshu (BL 18), Pishu (BL 20), Fengchi (GB 20), Cuanzhu (BL 2), Yiming (EX-HN 14), Guangming (GB 37), Taiyang (EX-HN 5), Yanglao (SI 6), Sibai (ST 2), Tongziliao(GB 1) were selected as main points, of which three to five points were punctured each time, but thefirst two were used necessarily. According to an overall differentiation of symptoms and signs auxiliarypoints were supplemented. The treatment was given once everyday with the manipulations of twirlingneedles plus slow or rapid insertion for reinforcing or reducing to make the needling sensation reach theeye regions. Twelve treatments made a course with an interval of 3 days between the two courses. Itwas shown that 15 cases were markedly effective (3l. 25 % ), 26 improved (54. 17% ), and 7 ineffec-tive (14. 58 % ). The total effective rate was 85.42%.