Photonic Transmitter Research Articles

A 25-Gb/s Monolithic Optical Transmitter With Micro-Ring Modulator in 130-nm SoI CMOS

An Si photonic transmitter is integrated in a 130-nm silicon-on-insulator complementary metal-oxide-semiconductor technology. A high-speed photonic ring modulator is designed for 25-Gb/s operation with an 8-dB extinction ratio. The ring is driven with a 2.4-Vpp swing using a low-power inverter driver. With a reference receiver, the 25-Gb/s link is measured with a bit error rate (BER) of 10-12. The total transmitter power consumption is 17 mW at 25 Gb/s for an energy efficiency of 680 fJ/b excluding laser and ring tuning power.

Photon transport in one-dimensional systems coupled to three-level quantum impurities

We discuss the transport properties of a single photon in a one-dimensional waveguide with an embedded three-level atom and utilize both stationary plane-wave solutions and time-dependent transport calculations to investigate the interaction of a photon with driven and undriven V- and Λ-systems. Specifically, for the case of an undriven V-system, we analyze the phenomenon of long-time occupation of the upper atomic levels in conjunction with almost dark states. For the undriven Λ-system, we find non-stationary dark states and we explain how the photon's transmittance can be controlled by an initial phase difference between the energetically lower-lying atomic states. With regard to the driven three-level systems, we discuss electromagnetically induced transparency in terms of the pulse propagation of a single photon through a Λ-type atom. In addition, we demonstrate how a driven V-type atom can be utilized to control the momentum distribution of the scattered photon.

First Monolithic Widely Tunable Photonic Coherent Transmitter in InP

An indium phosphide, monolithically integrated, photonic coherent transmitter with an integrated widely tunable laser is presented. A 20-Gb/s operation over 20-nm range, with quadrature phase-shift-keyed signal is demonstrated.

InP-Based Photonic Multiwavelength Transmitter With DBR Laser Array

We demonstrate an InP-based photonic multiwavelength transmitter realized by integrating an array of distributed Bragg reflector lasers with modulators in Mach-Zehnder configuration. An arrayed waveguide grating is used to multiplex the generated signals into a common optical output. The device is designed according to a generic integration concept, using standardized building blocks, and is fabricated in a multiproject wafer run. The device delivers up to 4 dBm of optical power into the fiber with a modulation data rate of 12.5 Gbps per transmission channel. The obtained performance makes it very promising for application in the next generation optical access networks as a key source in the central office part of the telecommunication systems.

Increased Upconversion Response in a-Si:H Solar Cells With Broad-Band Light

High-bandgap solar cells such as a-Si:H with a bandgap around 1.8-eV loose 50% of the incident solar energy due to transmittance of near infrared photons. Part of these photons can be converted into visible photons with a suitable upconverter and in this way can increase the photo response of solar cells in the near infrared. In this contribution, we demonstrate increased photo response of a-Si:H solar cells for sub bandgap light under broad-band light excitation of the upconverter. Broad-band excitation represents daily life and is more effective because simultaneously different wavelengths can be absorbed and converted. Bifacial a-Si:H solar cells were made with and without Gd2O2S: Er3+, Yb3+ upconverter attached at the back of the cells. A set-up was made to concentrate near infrared light from a solar simulator up to 25 times. I-V curves were measured of upconverter and reference solar cells. The upconverter solar cells showed a nonlinear and stronger increase in current with increasing concentration than the reference solar cells.

Efficient photon management with nanostructures for photovoltaics

Efficient photon management schemes are crucial for improving the energy conversion efficiency of photovoltaic devices; they can lead potentially to reduced material usage and cost for these devices. In this review, photon trapping mechanisms are discussed briefly in the beginning, followed by a summary of recent progress on a number of major categories of nanostructures with intriguing photon management properties. Specifically, nanostructures including nanowires, nanopillars, nanopyramids, nanocones, nanospikes, and so forth, have been reviewed comprehensively with materials including Si, Ge, CdS, CIGS, ZnO, etc. It is found that these materials with diverse configurations have tunable photon management properties, namely, optical reflectance, transmittance and absorption. Investigations on these nanostructures have not only shed light on the fundamental interplay between photons and materials at the nanometer scale, but also suggested a potential pathway for a new generation of photovoltaic devices.

Photonic Generation and Detection of W-Band Chirped Millimeter-Wave Pulses for Radar

Based on the frequency-to-time mapping approach, we generate frequency-modulated millimeter-wave (MMW) pulses with central frequencies up to the W-band by a shaped optical pulse excitation of an MMW photonic transmitter with an ultrawide band photodiode as its key component. A coherent detection is achieved via a terahertz time-domain spectroscopic setup. Two different kinds of chirped MMW waveforms are generated; one is a linearly chirped sinusoidal pulse and the other is produced by a frequency-stepped modulation. Through appropriate optical spectral design, the frequency-chirped MMW pulses with instantaneous frequencies sweeping from 120 to 60 GHz, and a time-bandwidth product of ~ 25 is experimentally demonstrated.

Manipulating electromagnetic wave with the magnetic surface plasmon based metamaterials

In this work, we have investigated the optical properties of the magnetic metamaterials (MMs) consisting of periodically/randomly arranged ferrite rods. By calculating the photonic band diagrams and transmittance, we have identified a photonic band gap originating from the magnetic surface plasmon (MSP) resonance. In addition, by tuning the external magnetic field (EMF), an MM slab can be used as an optical switch. Our simulated results also suggest that the optical properties of the MMs are robust against the position disorder and the size fluctuation of the ferrite rods. Moreover, by examining the relation between the transmittance and the EMF, we can optimize the EMF to realize the best switching effect. With the retrieved effective constitutive parameters eeff and μeff obtained from the effective-medium theory, the optimal EMF can be understood in a more clear manner.

Study of light propagation in human and animal tissues by Monte Carlo simulation

Monte Carlo Simulation for light propagation in different types of human and animal tissues has been performed using programming methods. During the simulation we have recorded the photon reflectance, transmittance and absorption in lung and dermis tissues of human, pig and rabbit and compared. Average values of total diffuse reflectance, transmittance and absorption have been calculated by the 10 simulations of 100,000 photons for these tissues at 633 nm. We have found that transmittance, reflectance and absorption are strongly dependent on tissue type and diffuse reflectance increases as the scattering coefficient (μs), increases or anisotropy (g), decreases, while diffuse transmittance increases as absorption coefficient (μa) or (μs) decreases, or as (g) increases.

A desktop X-ray monochromator for synchrotron radiation based on refraction in mosaic prism lenses

Focusing planar refractive mosaic lenses based on triangular prism microstructures have been used as an alternative approach for wide-bandpass monochromatization of high-energy X-rays. The strong energy dependence of the refractive index of the lens material leads to an analogous energy dependence of the focal length of the lens. The refractive mosaic lens, in comparison with the refractive lens of continuous parabolic profile, is characterized by a higher aperture because of reduced passive material. In combination with a well defined pinhole aperture in the focal plane, the transmittance of photons of an appropriate energy can be relatively high and photons of deviating energy can be efficiently suppressed. The photon energy can be tuned by translating the pinhole along the optical axis, and the bandwidth changed by selecting appropriate pinhole aperture and beam stop. This method of monochromatization was realised at the ANKA FLUO beamline using a mosaic lens together with a 20 µm pinhole and beam stop. An energy resolution of 2.0% at 16 keV has been achieved.

Enhanced Performance of Narrowband Millimeter-Wave Generation Using Shaped-Pulse-Excited Photonic Transmitters

We demonstrate a novel method to greatly enhance the narrowband millimeter-wave (MMW) power generation by use of a near-ballistic uni-traveling-carrier photodiode-based photonic transmitter (PT) excited by shaped optical pulses. The spectrum of the best tailored optical pulses is centered at 1545 nm and spread among 16 main frequency components (channels), each with a spectral width of 15.5 GHz and a spacing of 93 GHz. Compared with quasi-sinusoidal optical modulation, we achieve an enhancement in the spectral power density by ~25 times. The power-enhanced narrowband MMW signal can be tuned over ~80 GHz (60-142 GHz). In addition, we observe significant enhancement of MMW peak power with an increase of the reverse bias voltage.

Photon tunneling and transmittance resonance through a multi-layer structure with a left-handed material

This paper investigates the photon tunneling and transmittance resonance through a multi-layer structure including a left-handed material(LHM). An analytical expression for the transmittance in a five-layer structure is given by the analytical transfer matrix method. The transmittance is studied as a function of the refractive index and the width of the LHM layer. The perfect photon tunneling results from the multi-layer structure, especially from the relation between the magnitude of the refractive index and the width of the LHM layer and those of the adjoining layers. Photons may tunnel through a much greater distance in this structure. Transmittance resonance happens, the peaks and valleys appear periodically at the resonance thickness. For an LHM with inherent losses, the perfect transmittance is suppressed.

Millimeter-wave photonic wireless links for very high data rate communication

In this paper, recent progress in millimeter-wave (MMW) photonic gigabit wireless communication is reviewed. This technique is attractive partly because the MMW signal can be easily distributed from central to base stations through the use of a low-loss optical fiber. This radio-over-fiber approach facilitates the transmission of MMW signals. An MMW photonic transmitter, comprised of high-power photodiodes with integrated antennas for MMW signal broadcasting, is needed for signal generation only over the last mile. The development of several different low-noise optical MMW sources and high-power photonic transmitters and photodiodes for optical MMW wireless links is summarized. The performance of photonic wireless links with extremely high data rates (>10 Gbit s−1) developed based on these key components and using different modulation schemes is also reviewed. Finally, some advanced commercially available products and the prospects of a future gigabit wireless communication era are discussed.

High-Speed $W$-Band Integrated Photonic Transmitter for Radio-Over-Fiber Applications

A high-speed <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">W</i> -band integrated photonic transmitter is demonstrated. The presented integrated photonic transmitter is essentially developed with a near-ballistic uni-traveling-carrier photodiode integrated with a broadband front end through the flip-chip assembling technique. Technically, compared to our previous design, a <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">W</i> -band bandpass filter is exploited to significantly increase the transmitter IF modulation bandwidth. The demonstrated integrated photonic transmitter has a flat broad IF modulation response, as well as a broad optical-to-electrical (O-E) bandwidth. Specifically, the variation of the normalized IF modulation response, ranging from dc to around 13 GHz, is within 3 dB, and the normalized 3-dB O-E bandwidth is about 24 GHz. On the other hand, an up to 20-Gb/s high data-rate wireless transmission realized with the presented transmitter is demonstrated. The integrated photonic transmitter is expected to find applications in high-speed radio-over-fiber communications.

Ultra-efficient 10Gb/s hybrid integrated silicon photonic transmitter and receiver

Using low parasitic microsolder bumping, we hybrid integrated efficient photonic devices from different platforms with advanced 40 nm CMOS VLSI circuits to build ultra-low power silicon photonic transmitters and receivers for potential applications in high performance inter/intra-chip interconnects. We used a depletion racetrack ring modulator with improved electro-optic efficiency to allow stepper optical photo lithography for reduced fabrication complexity. Integrated with a low power cascode 2 V CMOS driver, the hybrid silicon photonic transmitter achieved better than 7 dB extinction ratio for 10 Gbps operation with a record low power consumption of 1.35 mW. A received power penalty of about 1 dB was measured for a BER of 10(-12) compared to an off-the-shelf lightwave LiNOb3 transmitter, which comes mostly from the non-perfect extinction ratio. Similarly, a Ge waveguide detector fabricated using 130 nm SOI CMOS process was integrated with low power VLSI circuits using hybrid bonding. The all CMOS hybrid silicon photonic receiver achieved sensitivity of -17 dBm for a BER of 10(-12) at 10 Gbps, consuming an ultra-low power of 3.95 mW (or 395 fJ/bit in energy efficiency). The scalable hybrid integration enables continued photonic device improvements by leveraging advanced CMOS technologies with maximum flexibility, which is critical for developing ultra-low power high performance photonic interconnects for future computing systems.

Device and Integration Technology for Silicon Photonic Transmitters

The device and integration technology for silicon photonic transmitters are reviewed in this paper. The hybrid silicon platform enables on-chip lasers to be fabricated with silicon photonic circuits and can be integrated in the CMOS back-end flow. Laser arrays from multiple die bonding and quantum well intermixing techniques are demonstrated to extend the spectral bandwidth from the laser array of the transmitter. Two modulator technologies, silicon modulators and hybrid silicon modulators, are also described.

Graphene-based photonic crystal

A novel type of photonic crystal formed by embedding a periodic array of constituent stacks of alternating graphene and dielectric discs into a background dielectric medium is proposed. The photonic band structure and transmittance of such photonic crystal are calculated. The graphene-based photonic crystals can be used effectively as the frequency filters and waveguides for the far infrared region of electromagnetic spectrum. Due to substantial suppression of absorption of low-frequency radiation in doped graphene the damping and skin effect in the photonic crystal are also suppressed. The advantages of the graphene-based photonic crystal are discussed.

Putting THz on the spot

A Gbit/s photonic transmitter with an integrated antenna system has been built and used to demonstrate a very high-speed wireless indoor network. The system, developed by researchers at Institute of Electronics, Microelectronics and Nanotechnology (IEMN) and Atom, Molecules and Laser Physics (PhLAM) laboratories, part of the French National Centre of Scientific Research (CNRS) based at the University of Lille, does not require an electrical power supply and can be plugged in to an optical fibre network of a building to create a wireless transmission system with a remote-supplied hotspot working up to gigabit data rates.

100 MHz Amplitude and Polarization Modulated Optical Source for Free-Space Quantum Key Distribution at 850 nm

We report on an integrated photonic transmitter of up to 100 MHz repetition rate, which emits pulses centered at 850 nm with arbitrary amplitude and polarization. The source is suitable for free space quantum key distribution applications. The whole transmitter, with the optical and electronic components integrated, has reduced size and power consumption. In addition, the optoelectronic components forming the transmitter can be space-qualified, making it suitable for satellite and future space missions.

Study of light propagation in human, rabbit and rat liver tissue by Monte Carlo simulation

Monte Carlo Simulation for light propagation in liver tissues of human and animal was done using Monte Carlo simulation. During the simulation we recorded the photon reflectance, transmittance and absorption of human, rabbit and rat liver tissues. Then their comparative studies were done. Average values of total diffuse reflectance, transmittance and absorption were calculated by the 10 simulations of 100,000 photons for these tissues at 633 nm. We found that diffuse reflectance increases as μ s increases or g decreases and diffuse transmittance increases as μ a or μ s decreases, or as g increases. It is also concluded that the radially resolved diffuse reflectance of the tissues decays exponentially of second order.