We give an overview the progress of our work in silicon photonic programmable circuits, covering the technology stack from the photonic chip over the driver electronics, packaging technologies all the way to the software layers. On the photonic side, we show our recent results in large-scale silicon photonic circuits with different tuning technologies, including heaters, MEMS and liquid crystals, and their respective electronic driving schemes. We look into the scaling potential of these different technologies as the number of tunable elements in a circuit increases. Finally, we elaborate on the software routines for routing and filter synthesis to enable the photonic programmer.

Millimeter wave semiconductor devices (Tunnel Diode, GUNN, IMPATT diode, BARITT diode) generate microwaves for a wide range of frequencies. A millimeter wave MOSFET consists of an NMOSFET or FINFET, and a millimeter wave generating diode (an adjustable resistor – in the case of a GUNN diode) in the drain region. The MOSFET and the millimeter wave diode are integrated as one device. When a gate voltage and a drain voltage are applied, the MOSFET is turned on, so as the GUNN diode, which generates RF signals modulated by the high-frequency signals from the gate. If the MOSFET is turned off, the Tunnel Diode / GUNN diode is also off. For an embedded IMPATT or BARITT diode, the millimeter wave device won’t be turned off by the MOSFET, due to the avalanche process, but the output signal is modulated by both the gate and drain voltages. An Optoelectronic or Photonic CMOS field effect transistor includes a built-in laser in either or both of the source and drain regions, or in the well regions (for Depletion-mode CMOS lasers), and multiple photon sensors in the channel or well regions. The MOSFET, lasers, and photon sensors are fabricated as one integral transistor. When the MOSFET is on, the lasers are turned on. When the MOSFET is off, the lasers are off. The Photonic CMOS is light emitting device. Traditional CMOS transistors are not. There are various types of Millimeter wave and Photonic MOSFETs. In this paper, we will explore the advantages of these devices, including improved cutoff frequency (ft or fmax), and signal to noise ratio (S/N) for RF CMOS, and higher Ion / Ioff for RF ASICs. We would also like to look into the possibility of completely replacing the Silicon Photonics, which forms silicon-based IC and lasers separately but on the same wafer- with nonlinear optoelectronic and millimeter wave CMOS, due to improve flexibility, much higher speed, and lower costs.

We have systematically studied multimode interferometer (MMI) splitters made from multiple tapered sections. The goal is to create a library of robust and low-loss splitters covering all splitting ratios (SR) for our silicon photonics platform based on 3 μm thick waveguides. The starting point is always a non-tapered canonical MMI either with general symmetry (canonical SRs 50:50, 100:0, and reciprocal ratios), with mirror symmetric restricted symmetry (canonical SRs 85:15, 50:50, 100:0, and reciprocal ratios), and with point-symmetric restricted symmetry (canonical SRs 72:28 and 28:72). Splitters of these three types are then divided into one to four subsections of equal length, leading to 12 possible different configurations. In each of these subsections, the width is first linearly tapered either up or down and then tapered back to its starting value ensuring mirror symmetry. For all twelve configurations, we carried out an extensive campaign of numerical simulations. For each given width change, we scanned the splitter length and calculated the power in the fundamental mode at the output as well as its relative phase. We then selected the designs with sufficiently low loss and mapped their SR as a function of either the change in width change or length, therefore creating systematic maps for the design of MMI splitters with any SR. Eventually, we selected and fabricated a subset of designs with SRs ranging from 5:95 to 95:5 in steps of 5% and validated their operation through optical measurements.

We designed and fabricated a novel MMI-based 1x4 power splitter with parabolic input and output ports by using particle swarm optimization. We achieved low insertion loss (<0.587 dB) and low imbalance (<0.369 dB) in the band of 1477 ~ 1646 nm with a compact size on the silicon-on-insulator platform. In the specific band of 1499 ~ 1626 nm, the insertion loss is less than only 0.488 dB. Additionally, we designed the 2:1:1:2 power splitter which has low insertion loss (<0.585 dB) and low targeted ratio error (<0.364 dB) in the wide band of 1457 ~ 1640 nm. The footprint is only 12.28 x 5 𝜇m2 and the fabrication limitations were also considered in both cases.

Accurate monitoring of the polarization within a waveguide is key to verifying the polarization fidelity in photonic integrated circuits and in verifying polarization during fiber alignment. Current testing methods require either a combined input/output fiber attachment or a tap/detector combination. These measure the coupled power but cannot monitor the polarization state near individual components. We have designed and tested foundry-compatible optical test-points for polarization monitoring. We study scatterers both for SiN and Si waveguides fabricated in the AIM Photonics foundry. We observe strong polarization effects in the light scattered from these elements when designed in certain geometries. When viewed with a short-wave infrared microscope, captured images displayed extinction values up to 30x between orthogonal polarizations for the engineered scattering elements. Finite-difference time-domain simulations were performed for each scattering element, corroborating experimental measurements but showing that even higher extinctions may be possible with further refinement.

Silicon photonics can have a major impact on the advancement of mid-IR photonics by leveraging the mature and reliable high-volume fabrication technologies already developed for microelectronic integrated circuits. Germanium, already used in silicon photonics, is a promising material for increasing the operating wavelength of Group-IV-based photonic integrated circuits beyond 8 μm and potentially up to 15 μm. High-performance InAs-based quantum cascade lasers grown on Si have been previously reported. In this work, we present InAs-based QCLs directly grown on Ge. The lasers operate near 14 μm with pulsed threshold current densities as low as 0.8 kA/cm² at room temperature.

The light detection and ranging (LiDAR) system is an emerging photonic technology in various applications such as autonomous vehicles, drones, robots, and high-precision 3D imaging. Since conventional LiDAR has employed mechanical beam-steering, the scanning speed is restricted and more power consumption is required. On the other hand, Silicon optical phased array (Si OPA) is a promising solution that can replace the mechanical scanning LiDAR due to the advantages of electrical scanning, small footprint, and low operating power. In this study, we demonstrated a 10 m distance measurement with Si OPA using the time-of-flight (ToF) method. We developed an optical pulse generator for high distance accuracy measurement utilizing an electrical pulse generator, radio frequency amplifier, diplexer, and distributed feedback laser diode to generate an optical output pulse with a 300 ps pulse width. The Si OPA was fabricated using complementary metal-oxide-semiconductor (CMOS) compatible processes with an 8-inch silicon-on-insulator wafer. Considering Si chip loss and beam-forming efficiency, the erbium-doped fiber amplifier was used at the front end of the input of Si OPA. An avalanche photodiode that has high speed and sensitivity was utilized as a receiver and the converted optical pulse was observed by a real-time oscilloscope. Using this ToF distance measurement platform, we achieved a 10 m distance measurement with a ranging error of 1.2 cm using Si OPA. Si OPA-based distance measurement platform will allow the realization of 3-dimensional image sensing and further improvement will enable high-accuracy long-distance measurement.

Quantum Cascade Lasers operating between 5.7 and 5.9 μm have been integrated on to a Germanium-on-Silicon (GoS) platform by flip-chip bonding. Sensing in this wavelength region is useful for a wide range of applications from monitoring caffeine and sweeteners, to analysis of oestrogen composition, which plays an important role in the metastatic spread of breast cancer. The approach demonstrated here uses laser bars incorporating twenty-four separate laser sources. Further enhancements of this system from the first generation are presented, including real-time power monitoring of the QCL output via fibrecoupling, more efficient gratings, improved support-structures and process improvements for both the QCL and GoS.

In this work, we report on all-silicon waveguide photodetectors utilizing surface state defects and bulk defects to sensitize the silicon to sub-bandgap light. The detectors are foundry fabricated, waveguide-integrated p-i-n junctions with post-processing consisting of HF acid exposure, ion implantation, annealing, or a combination of the three. HF exposure increases the photoresponse of the as-received detectors due to the increase in unpassivated surface states. The efficiency of surface state detection is greater than that for bulk defect detection in terms of mode overlap with the defected volumes of the silicon waveguide. Detectors in all cases have a 3dB bandwidth of 7GHz.

Scaling data centers to 200 Gbps/lane with direct detection may not provide sufficient link budget for optical switches. Analog coherent detection leverages phase and polarization of optical signals to scale efficiently without requiring digital signal processing and employs integrated lasers to maximize link budgets for optical switches. We report the first O-band silicon photonics coherent transmitter integrated with hybrid semiconductor optical amplifiers and tunable lasers. The laser demonstrated <6 dBm output power with ∼700 kHz linewidths across its 14 nm tuning spectrum. 64 Gbaud QPSK transmission was demonstrated with BER ∼4e-4 and ∼6.6 pJ/bit energy-efficiency when utilizing SiGe BiCMOS drivers.

As one of two mainstream platforms, photonics integrated circuits (PICs) on Si photonics platform benefits from the mature complementary metal-oxide-semiconductor (CMOS) manufacturing capabilities and allows for the processing of Si-based PICs with ultra-high volume and low cost. Recent studies of SiGeSn materials, which yield true direct bandgap with sufficient Sn incorporation, hold great promise for PICs featuring scalable, cost-effective, and power-efficient. While the exciting developments in bulk devices including lasers, light emitting diodes (LEDs), and photodetector were reported, the quantum wells (QWs) structure and devices have been investigated targeting the dramatically improved and/or novel device performance via variety of quantum confinement effects. In this work, we report the recent progress on SiGeSn QW development. Particularly, the study of MQW laser is presented. Devices with higher optical confinement factors exhibit clear lasing confirmed by the threshold characteristic and the emission spectra below and above threshold. Only spontaneous emission was observed with the thinner cap layer samples. On the other hand, samples with thicker cap layers of 250 and 290 nm exhibit clear lasing at 77 K with thresholds of 214 and 664 kW/cm², respectively. These promising results establish the guidance for the device design and pave the way for the SiGeSn QW devices towards future high-performance PICs on Si platform.

Simultaneous confinement of optical and mechanical modes is a requirement for an efficient Brillouin effect. In silicon-on-insulator (SOI) waveguides this challenge is solved by removing the silica under-cladding. Here we show that subwavelength engineering of the longitudinal and transversal geometries facilitates independent control of the photonic and phononic modes, hence allowing for strong Brillouin scattering. Here, we present a suspended silicon waveguide where a subwavelength lattice of lateral arms is used to separate the waveguide core from a phononic crystal.

The fabrication of Silicon nanostructures is still a point of interest to sustain a cheaper, faster, and more effective method. This work represents a comparison approach for the fabrication of SiNWs via modified Nanosphere lithography using polystyrene nanospheres (PS-NS) as templates against the Laser Ablation method. First, the Si type-p (111) wafer was treated with Oxygen/Argon Plasma to switch the wafer to the hydrophilic state to acquire an adequate nondispersive layer of PS-NS. The PS-NS was then dispersed in ethanol with a ratio [1:1]. The monolayer deposition on the wafer was achieved via 3-steps spinning with different rpm. The sizes of the PS-NS were then controlled by dry etching, using deep reactive ion etching (DRIE) for different periods to guide the size of the SiNWs. A silver (Ag) layer was then deposited on the structure to guide the silicon etching process via metal-assisted chemical etching (MACE) to control the length of the fabricated SiNWs. Another approach was to implement metal-assisted plasma etching (MAPE) first a layer of gold (Au) was sputtered on the sample using DC-Sputtering. The surface morphology of the structure has been investigated via field effect scanning electron microscopy (FE-SEM) and atomic force microscopy, while the optical characteristics were investigated via Fourier-transform infrared spectroscopy (FTIR) and photoluminescence (PL)

The mid-infrared (mid-IR) is an important wavelength range for vibrational absorption spectroscopy (e.g. for gas sensing, medical diagnostics, environmental monitoring), and thus there is a strong need for small and stable on-chip spectrometers. It is also desirable for it to be inexpensive to fabricate and for it to be able to perform high-resolution measurements over a wide bandwidth. To this end, we demonstrate two kinds of mid-IR thermo-optic type Fourier Transform spectrometers (FTS). Both variations of the device are designed to target a central wavelength of 3.8 μm and are based on the silicon-on-insulator platform. These two devices are verified by using them to retrieve the spectrum of a quantum cascade laser when it is tuned to different wavelengths. They have the potential to achieve higher resolution and bandwidth through subsequent design optimization, and could in future be integrated with mid-infrared photodetectors.

With the increased interest in silicon photonics, smart integration and packaging technologies are essential to transform photonic integrated circuits (PICs) into functional photonic systems. Especially for sensing, the currently existing standard packaging technologies are too expensive and bulky. We developed a solution for integrating a 1 mm x 1 mm sensor PIC with a single mode fiber and packaging it in a 1.5 mm inner-diameter metal protective tube. The concept relies on interfacing a grating coupler with a fiber from the back side of the PIC employing a 300 μm ball lens mounted in a laser-fabricated fused silica precision holder. It is shown that the additional insertion loss caused by the ball lens interface is very limited. A packaged sensor was achieved by sequentially mounting the holder on a ceramic ferrule, then the PIC on the holder and finally gluing a metal tube surrounding the assembly, taking care that the PIC surface is flush with the end face of the tube. The back side fiber interface ensures that the PIC’s surface remains accessible for sensing, while the tube protects the fiber-to-PIC interface. We demonstrated this concept by realizing a packaged phase shifted silicon Bragg grating temperature sensor operating around 1550 nm, which could be read out in reflection using a commercial interrogator. A temperature sensitivity of 73 pm/°C was found, and we demonstrated sensor functionality up to 180°C.

Rifampicin is an antimicrobial drug used to treat tuberculosis. The deterioration of a tuberculosis patient on rifampicin is a serious event with several possible causes. Rapid bedside measurement of rifampicin would enable clinicians to determine if patient deterioration was due to subtherapeutic levels and quickly correct the dosing. It would also support personalised dosing to maximise antimicrobial effectiveness whilst minimising side effects. The optimum therapeutic concentration range is 8 – 24 mg/L. We report ATR-FTIR spectroscopy data for the detection of rifampicin for bedside therapeutic drug monitoring (TDM). We demonstrate a limit of detection of 0.46 mg/L from 20 μL spiked whole blood samples. Using whole blood directly enables bedside measurements because it does not require centrifugation and pipetting to extract plasma, which are generally performed in a central laboratory. The absorption-concentration response had good linearity (R² = 0.998) up to the highest measured concentration of 100 mg/L. We apply this data to the design of a miniaturised mid-infrared sensor for TDM using silicon photonics. We present an analysis of the optimum interaction length for an evanescent waveguide sensor using the absorption of rifampicin and a numerical model to quantify the contributions of different system and device noise sources. These sensors can be made more sensitive than their benchtop equivalent because of the enhanced evanescent electric field strength and the increased power spectral density of tunable quantum cascade lasers.

A demonstration of an on-chip CO₂ gas sensor is reported. It is constructed by the integration of a MEMS-based thermal emitter, a scandium-doped aluminum nitride (ScAlN) based pyroelectric detector, and a sensing channel built on Si substrate. The integrated sensor has a small footprint of 13mm × 3mm (L×W), achieved by the replacement of bulky bench-top mid-IR source and detectors with MEMS-based thermal emitter and ScAlN-based pyroelectric detector, with their footprints occupying 3.15 mm × 3 mm and 3.45 mm × 3 mm, respectively. In addition, the performance of the integrated sensor in detecting CO₂ of various concentrations in N₂ ambient is also studied. The results indicate that the pyroelectric detector responds linearly to the CO₂ concentration. The integration of MEMS emitter, thermal pathway substrate, and pyroelectric detector, realized through CMOS compatible process, shows the potential for massdeployment of gas sensors in environmental sensing networks.

We present the development of Ge-on-Si waveguide-based devices for low-noise mid-infrared absorption spectroscopy of aqueous solutions, targeting wavelengths between 6 and 10 μm, that are able to reduce the relative intensity noise which is a key roadblock when measuring tiny analyte absorptions masked by a large background matrix absorption. The sensor uses a pair of integrated thermo-optic switches to continuously switch light between a reference waveguide and a sensor waveguide, so that common noise components can be cancelled out, even when the light source and photodetector are not integrated on the same chip.

Silicon nitride films with different compositions are exposed to ultraviolet light using both an LED and a laser as light sources (with a wavelength of 244 nm and 265 nm, respectively). Collected data suggests a decrease in refractive index following the exposure, and this can be used for permanently tuning the response of passive photonic devices. The effects of ultraviolet illumination on the material are studied combining observations of the change in the response of the photonic devices and analysis of exposed films.

In this work, a coupling strategy between mid-index SiNx and high-index active waveguides on the same silicon chip is proposed. To that aim, a sophisticated proof-of-concept integration between N-rich SiN and SOI micrometric waveguides is demonstrated achieving a <0.5 dB coupling for both TE/TM polarisations. The optical tunability of SiNx allows the mitigation of the mid-high refractive index discrepancy by interposing a SiO₂/Si-rich SiN double-layer anti-reflective coating, attaining back-reflections close to −20 dB. On that basis, it is shown numerically that a sub-dB interconnection between multiple-quantum well/dot stratified stacks and a silicon nitride passive waveguide is achievable, while keeping the introduced back-reflection level below −30 dB.

Silicon nitride (SiN) and silicon dioxide (SiO₂) are high-index and low-index refraction materials that qualify them for waveguide applications. Here, we present the SiN thin film by studying hydrogen content on the surface of the fabricated thin films. The SiN thin films were deposited via plasma-enhanced chemical vapor deposition (PECVD) on a P-type (111) Silicon wafer with a silicon dioxide layer of 1 micron and resistivity of ~ 100 ohm-cm. Hydrogen bonds are formed on the thin-film surface which causes high propagation loss as both N-H bonds and Si-H bonds lead to absorption in the telecom spectrum. Ammonia-free deposition was utilized using only silane (SiH₄) and nitrogen (N₂) as precursors gases in PECVD run to reduce the hydrogen content. Process pressure was kept constant at 650 mTorr, varying the (SiH₄) concentration, RF power and temperature. The thicknesses of the deposited thin films were kept ~300 nm determined by scanning electron microscopy (SEM). while surface roughness was examined using atomic force microscopy (AFM). The hydrogen bonding content was studied using Raman, Fourier-transform infrared spectroscopy (FTIR) and Photoluminescence.

As part of a future optical platform on-chip, we present a waveguide integrated tunable Fabry-Pérot Interferometer (FPI) for the long infrared wavelength range. The FPI consists of two parallel Bragg reflectors that are located at the ends of two waveguides facing each other. The waveguides are made of silicon and are suspended in air. The reflectors are realized as an alternating stack of silicon and air layers with high (H) and low (L) refractive index. The filter transmittance is evaluated by analytic calculations and electromagnetic finite difference time domain simulations. Filters with (HL)² layer stack show a full width half maximum of 270 nm and a peak transmittance of more than 25% at a wavelength of 9.4 μm at the first interference order in the simulation. It is evaluated by measurements. A MEMS actuator is used to tune the filter wavelength by changing the distance between both reflectors. A digital electrostatic actuator concept with a linear drive characteristic, designed for a large travel range up to 4 μm with a driving voltage of less than 30 V, is presented and evaluated together with the filter. The MEMS fabrication process for the structures is based on bonding and deep reactive ion etching (DRIE). The DRIE etch process was optimized, hereafter achieving a reduced roughness of less than 3 nm of the waveguide sidewalls. For transmission measurements the silicon waveguides are coupled to a laser source and a detector using optical fibers together with optical couplers on the chip. The filter performance was characterized in the range from 9μm to 9.4 μm.

We propose a polarization-diverse receiver for coarse wavelength division multiplexing. We fabricated polarization splitters and rotators as well as demultiplexers. The combined insertion loss and crosstalk were less than 4.0 dB and −10 dB, respectively.

Waveguide-to-fiber coupling is one of the key challenges in silicon photonics. Many approaches have already been experimentally demonstrated, such as grating couplers, inverse tapers, sub-wavelength structures, lensed fibers, photonic wire bonds, small-core fibers and separate waveguide interposers. However, it is difficult to find a concept that simultaneously offers broadband operation, polarization independency, low optical loss, simple fabrication and easy assembly. In this paper, the pros and cons of different concepts are reviewed. Then two alternative concepts are introduced for coupling light between 3 μm thick SOI waveguides and standard single-mode fibers with ultra-broadband (<500 nm bandwidth) and polarization independent operation. Experimental results with 1-2 dB loss per waveguide-fiber interface are reported for 1) separate 12 μm SOI interposers and 2) polymer lenses directly written to the end facets of the 3 μm SOI waveguides. The insertion loss of the interposer concept includes both the waveguide-interposer and interposer-fiber interfaces, as well as the loss of the interposer itself. The loss of the polymer lens concept includes the losses of the waveguide-to-lens, lens-to-air and air-to-fiber interfaces, as well as the loss of the directly written lens. Polymer lenses were also integrated on top of up-reflecting mirrors to demonstrate vertical fiber coupling. The scalability of the two concepts for low-cost silicon photonics packaging is also analyzed, taking into account the ability to align fibers passively into V-grooves or others such structures on the SOI chips.

A high-performance silicon waveguide-based electro-optical 3-to-8 decoder is proposed in this work. Generic 500x220 nm dimensions of the waveguide provide compatibility with other devices and circuits. The length of the active region is 4.5 microns. The n-to-m electro-optical switching circuits utilize both forward and reversed bias NOT gates with a voltage input of -2.5 V and 2.5 V, for logic zero and logic high, respectively. The 3-to-8 decoder showed an input power of the optical signal of 1.26 mW, which is distributed within the circuit, resulting in the maximum output power of approximately 0.3 mW on each of the 8 terminals. 20000 dB/cm mode loss is achieved with a logic input controlled by ±2.5 V. Results show that a data-rate of up to 100 Gbit/s is achieved.

An IR phototransistor is developed based on a feedback field effect transistor (FBFET) having a Si-pnpn structure composed of a p-type drain, n-type channel1, p-type channel2, and n-type source. The gate contact is eliminated in the new device, referred to as light-triggered (LT) FBFET, and a SiGe layer replaces the channel2 to absorb IR light. Instead of the bias applied to the gate contact, the open circuit voltage generated by IR absorption in the SiGe layer controls the current flowing from the drain to the source. With a 2-dimensional periodic array of LT-FBFETs, a metasurface having a resonance is constructed, leading to substantial enhancement of IR absorption in the SiGe layer. Owing to the near-zero subthreshold swing, high on/off ratio, and small off current of FBFETs, the LT-FBFET provides high external quantum efficiency and low static power dissipation.

The polarization filtering property of ideal PhC waveguides can be reinstated in the practical PhC slab waveguide also which was compromised due to the newly originated index guided modes in PhC slab waveguides. This can be done by controlling the side wall corrugation of the guiding portion of the PhC waveguide. By doing so, the guided TE, TM, and continuum of bands can be decoupled with each other for a sufficient range of operating frequencies. This way a TM-pass efficient polarization filters has been shown using silicon PhC slab waveguide, which gives a maximum extinction ratio of ≈ 43 dB, insertion-loss -0.5 dB along with ≈ 100 dB nm bandwidth in merely 20 periods long structure.

Single photon avalanche diodes (SPADs) are semiconductor photodiode detectors capable of detecting individual photons, typically with sub-ns precision timing. We have previously demonstrated novel pseudo-planar germanium-on-silicon SPADs with absorption into the short-wave infrared, which promise lower costs and potentially easier CMOS integration compared to III-V SPADs. Here we have simulated the dark count rate of these devices, using a custom solver for McIntyre’s avalanche model and a trap assisted tunnelling generation model. Calibration and fitting have been performed using experimental data and the results have highlighted areas in which the technology can be optimised.

Over a century ago, the study of blackbody radiation led to the development of quantum mechanics. A blackbody is a perfect absorber, absorbing all the electromagnetic light that illuminates it. There is no radiation passing through it, and none is reflected. Now, “bodies” with high absorption qualities are very important in many disciplines of research and technology. Perfect absorbers, for example, can be utilized as photodetectors, thermal pictures, microbolometers, an d thermal photovoltaic solar energy conversion. The Mid-infrared (MIR) wavelength spectrum has numerous advantages in a variety of applications. One of these uses is chemical and biological detection. In this paper, a metasurface mid -IR absorber based on the fractal technology of a doped silicon geometry resonator to realize wideband cross-fractal formation is introduced. The structure exhibits a broadband absorption within a wide range of IR wavelength spectrum extending from 3 to 9 μm. The structure was based on the Sierpinski carpet where different building blocks were simulated to reach the highest absorption. It is shown that light coupling over a broad wavelength range to the proposed fractal metamaterial absorber structure is due to multiple resonance mechanisms at different wavelengths. The propo sed structure is CMOS-compatible. Moreover, this proposed design opens the door to the development of new silicon -based absorbers for different applications such as energy harvesting and photodetection.

The coupling efficiency between optical fiber and blue-green light waveguide is pretty low since the limited size of sub-micrometer waveguides fabricated for the blue-green light waveguides, which largely limits the applications of photonic circuits at blue-green light wavelengths. Here we propose the mode field spot of wedge-shaped optical fiber lens is applied to couple the laser light into an optical phased array (OPA) by multiple waveguide channels. The numerical results show that compared to the optical coupling of green light waveguide by single-mode optical fiber, the coupling efficiency can be improved by 100% with 12 channels of OPA is coupled by a wedge-shaped optical fiber lens. This study may solve the coupling problems of blue-green light on photonic chips and have the great potential applications of photonic circuits at blue-green wavelengths.

This PDF file contains the front matter associated with SPIE Proceedings Volume 12426, including the Title Page, Copyright information, Table of Contents, and Conference Committee information.