Optoelectronic Research Articles

Programmable Optical Synaptic Linking of Neuromorphic Photonic-Electronic RTD Spiking Circuits.

Interconnectivity between functional building blocks (such as neurons and synapses) represents a fundamental functionality for realizing neuromorphic systems. However, in the domain of neuromorphic photonics, synaptic interlinking and cascadability of spiking optical artificial neurons remains challenging and mostly unexplored in experiments. In this work, we report an optical synaptic link between optoelectronic spiking artificial neurons based upon resonant tunneling diodes (RTDs) that allows for cascadable spike propagation. First, deterministic spiking is triggered using multimodal (electrical and optical) inputs in RTD-based spiking artificial neurons, which are optoelectronic (OE) circuits incorporating either micron-scale RTDs or photosensitive nanopillar-based RTDs. Second, feedforward linking with dynamical weighting of optical spiking signals between pre- and postsynaptic RTD artificial neurons is demonstrated, including cascaded spike activation. By dynamically weighting the amplitude of optical spikes, it is shown how the cascaded spike activation probability in the postsynaptic RTD node directly follows the amplitude of the weighted optical spikes. This work therefore provides the first experimental demonstration of programmable synaptic optical link and spike cascading between multiple fast and efficient RTD OE spiking artificial neurons, therefore providing a key functionality for photonic-electronic spiking neural networks and light-enabled neuromorphic hardware.

Elastic-acoustic, optical and thermoelectric investigation of Cu6AsS5X (X= Br, I) for renewable energy applications

First-principles computations examine the structure, optoelectronic, elastic-acoustic, and thermoelectric characteristics of Cu6AsS5X (X = Br, I). The renowned Perdew – Burke – Ernzerhoff generalized gradient approximation (PBEsol–GGA) was employed to compute the physical and elastic parameters; however, the energy band structure of Cu6AsS5Br and Cu6AsS5I has been more precisely determined by employing the Trans and Blaha technique of the modified Becke-Johnson (TB–mBJ) potential. The lattice constants of Cu6AsS5Br and Cu6AsS5I in the cubic structure increase from 10.24 Å to 10.27 Å as a consequence of an increase in atomic number (ionic size). Several properties are extracted from the computed density of state (DOS) and band structure (BS). The computed values for the gap between the valence and conduction bands indicate that the compounds are semiconducting. These compounds' prominent absorption peaks in the UV energy range suggest that argyrodites can be utilized for optoelectronic (OE) devices operating in this spectral region. The cubic compounds (C11, C12, and C44) elastics constants, as well as different parameters like Kleinman's parameters ζ, Hardness (H), melting temperature (Tm), Lame's constant, Zener anisotropy (A), acoustic behavior and its isotropy, and Poisson ratios (ʋ) are calculated. Furthermore, the thermoelectric properties have been calculated using the BoltzTrap package integrated into WIEN2K. The positive Seebeck coefficient (S), increased electrical conductivity (σ) and low thermal conductivity (k) indicates p-type semiconductors. These compounds' greater Figure of merit (ZT) shows their potential candidacy for thermoelectric applications

Programmable Tanh-, ELU-, Sigmoid-, and Sin-Based Nonlinear Activation Functions for Neuromorphic Photonics

We demonstrate a programmable analog opto-electronic (OE) circuit that can be configured to provide a range of nonlinear activation functions for incoherent neuromorphic photonic circuits at up to 10 Gbaud line-rates. We present a set of well-known activation functions that are typically used to trainDL models including tanh-, sigmoid-, ReLU- and inverted ReLU-like activations, introducing also a series of novel photonic nonlinear functions that are referred to as Rectified Sine Squared (ReSin), Sine Squared with Exponential tail (ExpSin) and Double Sine Squared. Experimentalvalidation for all theseactivation functions is performed at 10 Gbaud operation. The ability of the mathematically modelled photonic activation functions to train Deep Neural Networks (DNNs) has been verified through their employment in Deep Learning (DL) models for MNIST and CIFAR10 classification purposes, comparing their performance against corresponding NNs that utilize an ideal ReLU activation function.

ИЗМЕРЕНИЕ ФАЗОВЫХ И АМПЛИТУДНЫХ ШУМОВ ПОЛУПРОВОДНИКОВЫХ ЛАЗЕРОВ. МЕТОДИКА ИЗМЕРЕНИЙ. КАЛИБРОВКА. РЕЗУЛЬТАТЫ

The application of the frequency detector method for measuring the phase noise spectrum of semiconductor lasers has been experimentally demonstrated. The frequency detector is based on an unbalanced Mach-Zehnder interferometer and a photodetector. Analytical relations are obtained that allow one to choose the parameters of the Mach-Zehnder interferometer and perform experimental calibration of the measuring system. A technique is proposed for measuring the spectral components of the phase noise of lasers in the presence of a slow drift of the delay in fiber-optic lines and the frequency of the laser under study. The results of measuring the phase noise of a low-noise DX-1 laser module and high-noise laser diodes LSDLD155 (DFB) and LSFLD155 (FP) are presented. A strong correlation between the amplitude and phase noise levels of these lasers is found. The decisive influence of the noise of LSDLD155 and LSFLD155 lasers on the level of phase noise of optoelectronic (OE) microwave generators built using them is shown. It has been suggested that the low-noise laser module DX-1, which has a phase noise level 20–60 dB lower (in different parts of the spectrum), is not decisive in the level of phase and amplitude noise of an optoelectronic microwave generator. The investigated OE generator was built during the research in this work. The generator has low phase noise: −120 dBc/Hz at a frequency detuning of 10 kHz. Oscillation frequency 6.8 GHz; fiber optic delay line length 200 m.

Synthesis–dependent structural and optoelectronic properties of semicrystalline LiNbO3:SiO2 hybrid silicates

Polycrystalline ceramics of lithium niobate (LNO) were prepared via standard hydrothermal and solid–state chemistry reactions, and by the sol–gel method implementing acrylamide polymerization. Congruent LiNbO3 trigonal perovskite phases crystallized in the R3c (161) space group [3 m (C3v) polar point group] were obtained in all cases. Depending on the implemented synthetic route, the average grain and crystallite sizes were estimated to 127–895 nm and 35–40 nm, respectively. As prepared LNO powders were embedded in a–SiO2 mesoporous sonogel networks at different doping rates to conform LiNbO3:SiO2 semicrystalline hybrid silicates with differentiated structural and optoelectronic (OE) properties. Intensive morphological, structural, spectroscopic, and nonlinear optical (NLO) characterizations were performed to explore these novel composites’ structural and photophysical properties for lead–free ferroelectric and optical applications. Results show that the massive porosity of the sonogel glasses and related defective bonding environment promote generalized host–guest molecular interactions influencing the oxidation states and radiative transitions of the dopant compounds via surface–assisted mechanisms and chemical charge–transfers. Additionally, due to the ferroelectric nature of LNO and average macroscopic alignment attained along the polycondensation stage of the solid solutions, SHG activity was observed from the hybrid sonogel (HSG) phases. Bulk NLO susceptibilities and molecular hyperpolarizabilities were estimated within the 9.62 × 10−11 and 10−23 esu range, respectively. Finally, depending on the synthesis methodology and in–gap hybridized levels, energy gap (Eg) narrowing was also observed for all LNO/HSG glasses, showing Eg values as low as 3.05 eV.

Characterization of the optical-gain enhanced microwave-Q for a 20.97 GHz regeneratively mode-locked laser with a short ring-length.

By treating a regeneratively mode-locked laser with a short ring length of 5.85m as a coupled optoelectronic (OE) RF oscillator, the microwave quality factor (Q R F ) of its ring-cavity was characterized with the phase-shift approach. Specifically, the phase shift in the OE feedback loop of the mode-locked laser was varied, and the corresponding frequency shift in the photodetected first harmonic of its emitted pulse train was measured. An optical-gain enhanced Q R F of ∼5.8×104 was measured, which is an order of magnitude larger than the Q R F estimated for the same cavity before regenerative mode-locking. The experimental results were then compared with theoretical models developed to estimate the optical-gain enhanced Q R F of coupled OE oscillators.

Systematic analysis of different low-pass filter cut-off frequencies on lumbar spine kinematics data and the impact on the agreement between accelerometers and an optoelectronic system

A necessary step in the validation of accelerometers for the measurement of spine angles is to determine the levels of agreement with current gold standard methods. However, agreement may be a function of filtering parameters. We aimed to (1) systematically determine the effect of different filter frequency cut-offs on the peak range of motion (ROM) during forward bending as measured by accelerometers and an optoelectronic (OE) system, (2) explore the influence of filtering on agreement between systems, and (3) determine the difference in peak ROM measurement between these systems. Accelerometers and OE sensors were attached at L2, L4, and S1 of 20 asymptomatic female participants for a guided flexion trial. Signals were then iteratively low-pass filtered with cut-off frequencies ranging from 14 Hz to 1 Hz and peak range of motion outcome measures were compared between systems. Peak ROM was minimally affected by filter cut-off frequency for both accelerometer and OE system. The difference in peak ROM between difference cut-off frequencies were maximum 0.66°, median 0.18° and minimum 0.06° for accelerometer derived values and maximum 0.23°, median 0.08° and minimum 0.03° for the OE system. The maximum difference across the filtering frequencies was 0.62° and the largest difference between the two systems (with outliers removed) was 0.82°. Cut-off frequencies ranging from 14 to 1 Hz had little effect of peak lumbar spine ROM during low velocity (6°/s) forward bending, regardless of motion capture method. Filtering cut-off frequency had little effect on the differences between the accelerometer and OE system and similar measurements can be achieved using accelerometers compared to OE systems.

DFT study of the structural, electronic and optoelectronic properties of PDAPb(I1−x Br x )4 perovskites

PDAPb(I1−x Br x )4 (NH3CH2CH2CH2NH3Pb(I1−x Br x )4, 0 ⩽ x ⩽ 1) is a two-dimensional Dion–Jacobson phase perovskite that has attracted extensive attention owing to its potential as a promising candidate for optoelectronic (OE) application. Herein, the structural, electronic, and optoelectronic properties of PDAPb(I1−x Br x )4 by gradually substituting I with Br at 1/4 intervals starting from PDAPbI4 based on the first-principles approach of density functional theory. With the increase in Br content, the crystal volume of PDAPb(I1−x Br x )4 decreases nonlinearly. The electronic structure shows the bandgap presents an increasing trend (PDAPbI4 (2.272 eV)–PDAPb(I0.5Br0.5)4 (2.475 eV)–PDAPbBr4 (2.678 eV)). The most stable structure that can be obtained from the calculated formation energy (E f) is PDAPb(I0.5Br0.5)4. The partial density of states reveals that the contribution of electrons is mainly related to the [PbX6]4− (X = I, Br) octahedron. The organic molecule PDA is almost not involved in the conductivity. The optoelectronic properties indicates that the characteristic peaks of the optoelectronic parameters of PDAPb(I1−x Br x )4 coincide with the bandgap. The doping ratio of 0.5 not only has the largest dielectric coefficient, but also has good conductivity in the visible region. Therefore, PDAPb(I0.5Br0.5)4 is extremely promising for applications in OE industry. This study provides some theoretical guidance for experiments and the search for new efficient and environmentally friendly OE materials.

Dion-Jacobson phase lead-free halide (PDA)MX4 (M=Sn/Ge; X=I/Br/Cl) perovskites: A first-principles theory

Hybrid lead (Pb) halide perovskites are widely regarded as promising materials for next generation of photovoltaic (PV) and optoelectronic (OE) devices owing to their high power conversion efficiency (PCE). To obtain green lead-free and excellent materials, the structural, electronic and optical properties of tin (Sn) and germanium (Ge) based single-layer Dion-Jacobson (DJ) phase perovskites (PDA)MX4 (M ​= ​Sn/Ge; X ​= ​I/Br/Cl) systems are investigated by carrying out first-principles theory. The calculation results indicate that all perovskites (PDA)MX4 have good thermal stability (at 300K), and the structural stability increases in the order of I–Br–Cl. These compounds are direct bandgap semiconductors, ranging from 1.26 to 1.81 ​eV ((PDA)SnX4) and 1.44–2.26 ​eV ((PDA)GeX4). Density of states (DOS) reveals that the band edge state mainly comes from the M-X bond and the organic molecule PDA is not directly involved in the contribution. Compared to Ge-based perovskites, the bandgap range of Sn-based perovskites is not only closer to the optimal bandgap requirement for perovskite solar cells (PSCs), but the optical properties reveal a slightly higher absorption coefficient for Sn-based perovskites in the visible light range. This suggests that (PDA)SnX4 perovskites are more favorable for PSCs applications. The theoretical study can provide strong support for the development of high-level perovskites materials in PV and OE devices.

Comparative Study and Analysis of Si/SIC and GaN/AlGaN Based Pin Diode Photo Sensors

The research work has been done through a comparative study and analysis of Si, Sic And GaN, AlGaN based pin diode photo sensors. The devices which are made up of grapheme based materials are actually grapheme based materials which have the properties of good optical and good electrical which can be used as photo detection. So the photo sensors made up of grapheme based materials are expected to perform in high speed opto electronic devices. The author has done a comparison in the analysis of Forward characteristics, Carrier mobility, reverse recovery time, isolation loss and insertion loss of the exotic pin based photo detectors of GaN/ AlGaN and Si SIC based devices for opto electronics applications.

Heterometal Grafted Metalla-ynes and Poly(metalla-ynes): A Review on Structure-Property Relationships and Applications.

Metalla-ynes and poly(metalla-ynes) have emerged as unique molecular scaffolds with fascinating structural features and intriguing photo-luminescence (PL) properties. Their rigid-rod conducting backbone with tunable photo-physical properties has generated immense research interests for the design and development of application-oriented functional materials. Introducing a second d- or f-block metal fragment in the main-chain or side-chain of a metalla-yne and poly(metalla-yne) was found to further modulate the underlying features/properties. This review focuses on the photo-physical properties and opto-electronic (O-E) applications of heterometal grafted metalla-ynes and poly(metalla-ynes).

Comprehensive vector analysis for electro-optical, opto-electronic, and optical devices.

High-performance electro-optical (E-O), opto-electronic (O-E), and optical (O-O) devices are widely used in optical communications, microwave photonics, fiber sensors, and so on. Measurement of the amplitude and phase responses are essential for the development and fabrication of these devices. However, the previous methods can hardly characterize the E-O, O-E, and O-O devices with arbitrary responses. Here we propose a comprehensive vector analyzer based on optical asymmetrical double-sideband (ADSB) modulation to overcome this difficulty. The ADSB solves the problem of frequency aliasing and can extract information from both the +1st- and -1st-order sidebands. Thus, most devices in photonic applications, including phase modulators, can be characterized. In the experiment, a commercial photodetector, a phase modulator, and a sampled FBG are used as the O-E, E-O, and O-O devices under test, respectively. A frequency resolution of 2 MHz, an electrical sweeping range of 40 GHz, and an optical sweeping range of 80 GHz are achieved.

Optical coupling with flexible polymer waveguides for chip-to-chip interconnects in electronic systems

This contribution discusses technology development for the realization of chip-to-chip interconnection based on flexible optical waveguides. Two approaches for optical coupling between waveguides and active devices are presented. Both approaches built on the planar polymeric optical multimode waveguides integrated on flexible substrates (PEN-foil). This waveguides structured using UV-photolithography and Ormocere-materials feature low optical attenuation below 0.05 dB/cm. The first approach for coupling between optical waveguides uses a bidirectional interruption-free waveguide coupler. The principle bases on directional core-core-coupling and allows for adjustable coupling ratio by tuning the overlap area. In addition, an asymmetric coupling behavior depending on the coupling direction due to a bending of one of the coupling waveguides is achieved. This coupling method shows supremacy for optical bus systems where tunable, asymmetric coupling ratios are desired. The second optical coupling approach for waveguide-to-chip coupling bases on out-of-plane optics. Direct integration of 45° micro-mirrors into polymer waveguides using dicing process is investigated. Two approaches for optoelectronic (OE) subassembly with flexible optical waveguides are considered one with flip-chip bonded and one with embedded OE-devices. Using optical characterization the influence of fabrication parameters on the optical performance of diced mirrors with insertion power loss measurement is derived and presented.

Tuning the Band-gap of Pt(II) Di-ynes and Poly-ynes by Incorporating Cl(CO)3Re(I) side-chain

Band-gap (Eg) of a material is an important criterion for application in opto-electronic (O-E) devices.1,2 Both low- and high Eg materials are useful and being synthesized by chemists via core structure modification, functional group variation and metal incorporation.3,4 We present herein computational study on the impact of incorporation of a Re(I) side-chain in 2,2’-bipyridine based Pt(II) di-ynes and poly-ynes. The density functional theory (DFT) calculation shows that the incorporation Cl(CO)3Re(I) as pendant functionality in 2,2’-bipyridine-based main-chain Pt(II) di- ynes and poly-ynes significantly reduce the Eg of the materials. Furthermore, to assess the role of positional isomerism, we compare the electronic structure and properties of 5,5’-and 6,6’- disubstituted 2,2’-bipyridine incorporated homo- and hetero-bimetallic diynes and poly-ynes . We find that the coordination of ReCO3 Cl moiety to Pt(II) di-yne introduces new Re(I)-localized highest occupied molecular orbital (HOMO) and the lowers the Eg by around 0.7 eV. Furthermore, our experimental results reveal that 5,5’-disubstituted 2,2’-bipyridine-based hetero-bimetallic di- ynes and polyynes are better materials for future O-E device applications.

Coherent transceiver operating at 61-Gbaud/s.

We use 85-Gs/s digital-to-analog convertor (DAC), 85Gs/s analog-to-digital convertor (ADC), commercial optoelectronic (OE) components with an overall electronic 3dB-bandwidth of less than 15GHz, and novel digital signal processing (DSP) algorithms implemented in CMOS to realize real time coherent transceiver operation at a record baud rate of 61-Gbaud/s. Novel DSP approaches for mitigating narrow filtering effect is critical to acquire data clock, and to improve modem performance. With transmitter pre-emphasis, novel timing recovery, and soft output maximum likelihood sequence estimation (MLSE), we are able to achieve error free operation of single carrier 200-Gbit/s polarization division multiplexed quadrature phase shift keying (PDM-QPSK) after forward error correction (FEC) at 15.2dB OSNR with pre-FEC error rate of 1.4E-2, and single carrier 400-Gbit/s PDM 16-ary quadrature amplitude modulation (16QAM) after FEC at 30.2dB OSNR with pre-FEC error rate of 9.5E-3. Error free transmission for 200-Gbit/s PDM-QPSK and 400-Gbit/s PDM-16QAM was achieved after 1200km propagation with 6dB link margin and 80km propagation respectively.

Opto-Electronic Chip-on-Film Packaging Technology Using Low-CTE Fluorinated Polyimide Optical Waveguide Films

We have developed a new type of single-mode optical waveguide film with a low coefficient of thermal expansion (CTE). The low-CTE film was fabricated by sandwiching a fluorinated polyimide optical waveguide layer between low-CTE polyimide layers. Its CTE is less than one-tenth that of conventional polyimide optical waveguide films. We fabricated opto-electronic (OE) films with coplanar waveguide lines on the film surface using this low-CTE film. We confirmed that the film has good optical, electrical, and mechanical characteristics. This low-CTE OE film can be used to integrate optical and electrical devices on a film.

Quantified Reliability of Aerospace Optoelectronics

The attributes of and challenges in the recently suggested probabilistic design for reliability (PDfR) concept, and the role of its major constituents - failure oriented accelerated testing (FOAT) and physically meaningful predictive modeling (PM) - are addressed, advanced and discussed. The emphasis is on the application of the powerful and flexible Boltzmann-Arrhenius-Zhurkov (BAZ) model, and particularly on its multi-parametric aspect. The model can be effectively used to analyze and design optoelectronic (OE) devices and systems with the predicted, quantified, assured, and, if appropriate and cost-effective, even maintained probability of failure in the field. The numerical example is carried out for an OE system subjected to the combined action of the ionizing radiation and elevated voltage as the major stimuli (stressors). The measured leakage current is used as a suitable characteristic of the degree of degradation. It is concluded that the suggested methodology can be accepted as an effective means for the evaluation of the operational reliability of the aerospace electronics and OE systems and that the next generation of qualification testing (QT) specifications and best practices for such systems could be viewed and conducted as a “quasi-FOAT,” a sort of an “initial stage of FOAT” that adequately replicates the initial non-destructive segment of the previously conducted comprehensive “full-scale” FOAT.

A 40 Gb/s Optical Bus for Optical Backplane Interconnections

Optical technologies have received large interest in recent years for use in board-level interconnects. Polymer multimode waveguides in particular, constitute a promising technology for high-capacity optical backplanes as they can be cost-effectively integrated onto conventional printed circuit boards (PCBs). This paper presents the first optical backplane demonstrator based on the use of PCB-integrated polymer multimode waveguides and a regenerative shared bus architecture. The backplane demonstrator is formed with commercially-available low-cost electronic and photonic components onto conventional FR4 substrates and comprises two opto-electronic (OE) bus modules interconnected via a prototype regenerator unit. The system enables interconnection between the connected cards over four optical channels, each operating at 10 Gb/s. Bus extension is achieved by cascading OE bus modules via 3R regenerator units, overcoming therefore the inherent limitation of optical bus topologies in the maximum number of cards that can be connected to the bus. Details of the design, fabrication, and assembly of the different parts of this optical bus backplane are presented and related optical and data transmission characterisation studies are reported. The optical layer of the OE bus modules comprises a four-channel three-card waveguide layout that is compatible with VCSEL/PD arrays and ribbon fibres. All on-board optical paths exhibit insertion losses below 13 dB and intra-channel crosstalk lower than -29 dB. The robustness of the signal distribution from the bus inputs to all respective bus output ports in the presence of input misalignment is demonstrated, while 1 dB input alignment tolerances of approximately ±10 μm are obtained. The electrical layer of the OE bus modules comprises the essential driving circuitry for 1×4 VCSEL and PD arrays and the corresponding control and power regulation circuits. The interface between the optical and electrical layers of the bus modules is achieved with simple OE connectors that enable end-fired optical coupling into and out of the on-board polymer waveguides. The backplane demonstrator achieves error-free (BER <; 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-12</sup> ) 10 Gb/s data transmission over each optical channel, enabling therefore, an aggregate interconnection capacity of 40 Gb/s between any connected cards.

Terabit/Sec VCSEL-Based 48-Channel Optical Module Based on Holey CMOS Transceiver IC

We report here on the design, fabrication and characterization of 48-channel parallel optical transceivers demonstrating terabit/sec data transfer rate. The 0.48 Tb/s transmit plus 0.48 Tb/s receive throughput was achieved using a second-generation single-chip holey CMOS transceiver IC. In addition to 24 receiver (RX) and 24 laser diode driver circuits, the 5.2 mm × 5.8 mm single CMOS chip incorporates 48 through-substrate optical vias (holes), one for each transmitter (TX) and RX channel. A complete holey Optochip is formed following direct flip-chip attachment of 24-channel 850-nm VCSEL and PD arrays. The 48 optical vias enable optical access to the 24 VCSELs and 24 PDs. The holey Optochip concept provides a dense chip-scale package which is fully compatible with industry-standard top emitting/detecting 850-nm VCSELs/PDs providing optimized high-speed performance through close integration of the optoelectronic (OE) devices with their drive electronics. Furthermore, the optical vias and OE devices are arranged in a 4 × 12 array on 250 μm × 250 μ m pitch to facilitate direct fiber-coupling to a standard 4 × 12 multi-mode fiber array. The Optochips are packaged into complete modules by flip-chip soldering to high-density, high-speed organic carriers. A pluggable connector soldered to the bottom of the carrier provides all module electrical I/O. The 18 mm × 18 mm overall module area is dictated by the 0.8 mm-pitch ball grid array (BGA) of the organic carrier and connector. Fully functional holey Optomodules with 24 TX and 24 RX channels operate up to 20 Gb/s/ch achieving efficiencies (including both TX and RX) of 7.3 pJ/bit. The terabit/sec data rate (480 Gb/s TX + 480 Gb/s RX) is highest reported for single-chip CMOS transceiver modules.

Near-Ballistic Unitraveling-Carrier Photodiode-Based V-band Optoelectronic Mixers With Low Upconversion Loss and High Operation Current Performance Under Optical IF Signal Injection

We demonstrate near-ballistic unitraveling-carrier photodiode (NBUTC-PD)-based V-band (50-75 GHz) optoelectronic (OE) mixers which can upconvert the V-band optical local-oscillator (LO) and intermediate-frequency (IF) signals. The optical LO and IF signals share a single erbium-doped optical fiber amplifier (EDFA) which means that the mixing performance of the device can be optimized by properly adjusting the ratio between the injected optical LO and IF power to the EDFA. The utilization of the strong nonlinearity of the ballistic transport of the electrons in the NBUTC-PD under a reverse bias regime means that our device achieves a low upconversion loss ( -6 dB) under a very high operating current (23 mA) in V-band (60 GHz). We are able to improve the operating current at the V-band over that previously reported for UTC-PD-based OE mixers. This is made possible by an increase in the optimum operating voltage from the near forward bias (0 V) to the reverse bias regime (-1.7 V).