Optoelectronic Mixer Research Articles

Large Signal Model of Heterojunction Bipolar Transistor InP/InGaAs as an Optoelectronic Mixer

A large-signal model of InP/InGaAs single Heterojunction Bipolar Transistor (HBT) has been developed considering spectral performance and mixing. This model is based on Gummel Poon BJT model. HBT InP/InGaAs has been modeled and analyzed in this paper as an optoelectronic mixer (OEM). The HBT proposed was simulated by considering the wavelength of 1310 nm for an up-conversion frequency of 30 GHz. Its characteristics was further investigated to develop the appropriate structure device for OEM application. This proposed HBT InP/InGaAs can be potentially implemented in the broadband Radio over Fiber (RoF) system to perform photodetection and frequency up-conversion.

Optoelectronic Mixer Based on Graphene FET

We present optoelectronic mixing phenomenon in graphene FET (GFET) and give a brief analysis for the first time. Demonstrated by a measurement system, two operating modes of optoelectronic mixer (OE-mixer) circuits are proposed, either of them mixing optical and electrical signals directly using a single GFET. Optoelectronic conversion losses of 24 and 35 dB are obtained in a 50-Ω impedance system, respectively. GFET OE-mixer might be of strong importance for radio over fiber systems, millimeter wave, and terahertz frequencies applications.

The Analysis of Implement of SiPM in LDRI System

LDRI system stands for Laser Dynamic Range Imager. It has been used in STS-114 mission in 2005 as the main sensors to realize an on-orbit inspection of the thermal protection system which covers the Orbiter spacecraft. The basic of LDRI is phase discrimination and the key technology is the realization of optoelectronic mixing (OEM) using ICCD. Unfortunately, 2 main drawbacks arise from the usage of ICCD, including the high voltage (~2000V) of PMT drivers and the difficulties in high voltage modulations. SiPM is a rather novel detector which has the similar performances as PMT does but only requires a driving voltage of about 30V. Recently, the SiPM based OEM has been proved and this implies the implement of SiPM in LDRI system. In this paper, the basic of LDRI and SiPM are summerized and some theoretical analysis and simulations are made to verify the feasibility of implement of SiPM in LDRI system. The results show that SiPM is capable of realizing phase discrimination regardless of the high driving voltage and difficulties in modulations. The mean range error is found to be no more than 0.4mm within a range of 5m and an average incident power of 6nW.

Self-Heterodyne Spectrometer Using Uni-Traveling-Carrier Photodiodes for Terahertz-Wave Generators and Optoelectronic Mixers

We demonstrate a self-heterodyne terahertz (THz) frequency-domain spectrometer in which commercially available uni-traveling-carrier photodiodes (UTC-PDs) are used as optical-to-electrical (O/E) converter and optoelectronic mixer (OEM). The optical intensity beat generated by mixing two frequency-detuned free-running 1.55 $\mu$ m laser diodes (LDs) is used as a source for the photomixing at the O/E converter, and as an optical local oscillator (LO) signal for the OEM. The frequency of the optical LO signal is coherently shifted with an electrooptic frequency shifter so that the heterodyne detection is realized using free-running LDs for the beat source. We investigate the sensitivity characteristics of the spectrometer as functions of diode bias voltage and optical LO level. The maximum signal-to-noise ratio of 47 dB for the RF power of $-$ 16 dBm is achieved at 300 GHz with the lock-in time constant of 23.4 ms. The standard deviation of the phase measurement is 0.73 $^\circ$ , where the amplitude noise limited standard deviation is 0.25 $^\circ$ . We measure the system response ranging from 200 to 1450 GHz and find that it fits well the response which is calculated using the frequency characteristics of the output power of the UTC-PDs. Our results show that UTC-PDs are promising candidates not only for the high-power terahertz wave generator, but also for the wide-band THz-OEM. Integration of UTC-PDs with free-running LDs on the same substrate with the same process steps would significantly reduce the cost and size of the present spectrometer.

Highly efficient terahertz detection by optical mixing in a GaAs photoconductor

It is shown from accurate on-wafer measurement that a low-temperature-grown GaAs photoconductor using a metallic mirror Fabry-Perot cavity can serve as highly efficient optoelectronic heterodyne mixer in the terahertz frequency range. Conversion losses of 22 dB at 100 GHz and ∼27 dB at 300 GHz were measured, which is an improvement by a factor of about 40 dB as compared with the previous values obtained with photoconductors. Experimental results are interpreted satisfactorily by means of a simple electrical model of the optoelectronic mixing process.

Structural parameters improvement of an integrated HBT in a cascode configuration opto-electronic mixer

We analyze an integrated electrically pumped opto-electronic mixer, which consists of two InP/GaInAs hetero junction bipolar transistors (HBT), in a cascode configuration. A new HBT with modified physical structure is proposed and simulated to improve the frequency characteristics of a cascode mixer. For the verification and calibrating software simulator, we compare the simulation results of a typical HBT, before modifying it and comparing it with empirical reported experiments. Then we examine the simulator on our modified proposed HBT to prove its wider frequency characteristics with better flatness and acceptable down conversion gain. Although the idea is examined in several GHz modulation, it may easily be extended to state of the art HBT cascode mixers in much higher frequency range.

Silicon photomultiplier-based optoelectronic mixing

Silicon photomultiplier (SiPM)-based optoelectronic mixing (OEM) is studied for the first time. The validity of SiPM-based OEM is experimentally verified. Compared with the avalanche photodiodes-based OEM, the SiPM-based OEM is less noisy and easy to realize for its low voltage operation and high responsivity.

Bidirectional Millimeter-Wave Radio-Over-Fiber System Based on Photodiode Mixing and Optical Heterodyning

We demonstrate a bidirectional millimeter-wave (mmW) radio-over-fiber system based on the use of a p-i-n photodiode (PD) biased in the nonlinear regime. Since frequency down-conversion and photodetection are carried out by a single photodiode, the base station (BS) architecture is simplified. Down-link transmission employs an optical heterodyning technique for mmW generation and remote local oscillator (LO) delivery to BSs. The up-link scheme uses the electrical port of the PD as an input for optoelectronic mixing with the remotely delivered LO. Up-link and down-link have been successfully demonstrated for 397 Mbps and 794 Mbps binary phase-shift keying complying with the 60 GHz ECMA 387 standard. Error vector magnitude measurements and theoretical analysis are discussed as regards optimal PD bias conditions. It is shown that PD can be used in this bidirectional system without any switching of the PD bias.

Photonic Heterodyne Pixel for Imaging Arrays at Microwave and MM-Wave Frequencies

The use of photonic heterodyne receivers based on semiconductor optical amplifiers to be used in imaging arrays at several GHz frequencies is evaluated. With this objective, a imaging array based on such photonic pixels has been fabricated and characterized. Each of the receiving optoelectronic pixels is composed of an antipodal linear tapered slot antenna (LTSA) that sends the received RF signal directly to the electrical port of a semiconductor opticalamplifier (SOA) acting as the optoelectronic mixer. Both the local oscillator (LO) and the intermediate frequency (IF) signals are directly distributed to/from the array pixels using fiber optics, that allows for remote LO generation and IF processing to recover the image. The results shown in this work demonstrate that the performances of the optoelectronic imaging array are similar to a reference all-electronic array, revealing the possibility of using this photonic architecture in future high-density, scalable, compact imaging arrays in microwave and millimeter wave ranges.

Performance Characterization of Heterojunction Bipolar Transistor as an Optoelectronic Mixer

This paper explains the development of physical model Heterojunction Bipolar Transistor (HBT) andcharacterizes its performance as an optoelectronic mixer (OEM). HBT has been identified as a suitabledevice to be implemented in optoelectronic mixers by simultaneously photodetecting an intensitymodulated laser beam at 1550nm and frequency translating the detected signal to a higher or lowerfrequency which can provide high mixing efficiency and required condition for an oscillator. The HBTOEM was designed, modeled and simulated by using APSYS Crosslight software. Data from thesimulation such as the gummel plot, energy band diagram and other characteristics have been generatedand analyzed. The device was analyzed considering 1550nm wavelength with up to 30GHz modulatingsignal frequency. Hence, the designed HBT is found to be possible for the implementation of thebroadband RoF system as it can perform the photodetection, amplification and frequency conversionsimultaneously as required at RoF remote antenna unit..

Optoelectronic Mixing in Electroabsorption Waveguides under Very High Optical Power

Optoelectronic Mixing in Electroabsorption Waveguides under Very High Optical Power

Optoelectronic Mixing in Electroabsorption Waveguides under Very High Optical Power

We examine the performance of the electroabsorption (EA) mixer at high optical power. It is shown that the EA mixer can theoretically achieve an external conversion loss of ∼0 dB for waveguides that can handle very high optical power. The analysis is consistent with data deduced from prior experiments.

Interview

Professor Junghwan Kim from Sejong University in Korea talks about the research behind his Letter ‘High up-conversion gain optoelectronic mixer using uni-travelling carrier phototransistors’ page 583.

High upconversion gain optoelectronic mixer using uni-travelling carrier phototransistors

The optoelectronic mixing performance of a uni-travelling carrier heterojunction phototransistor (UTC-HPT) was compared with its performance as a photodiode (PD). The upconverted output power in HPT mode was 24 dBm higher than in PD mode.

A Silicon Balanced Subharmonic Optoelectronic Mixer for 60-GHz Fiber-Wireless Downlink Application

We demonstrate a 60-GHz fiber-wireless downlink using a balanced subharmonic optoelectronic mixer based on a silicon avalanche photodiode (APD) pair fabricated with standard 0.25-μm bipolar complementary metal-oxide-semiconductor technology. Conversion efficiency of this new type of optoelectronic mixer is 11 dB better than that of the previously reported single APD mixer. We achieve downlink transmission of 25-Mb/s 32 quadrature-amplitude modulation data with the minimum error-vector magnitude of 2.4%.

Optoelectronic Mixer Based on Composite Transparent Gate InAlAs–InGaAs Metamorphic HEMTs

In this study, sputtered indium-tin-oxide (ITO) formed ITO/Au/ITO was used to form composite transparent gate InAlAs-InGaAs metamorphic HEMTs (CTG-MHEMT), with an optoelectronic mixer significantly markedly improved front-side optical coupling efficiency. The proposed CTG-MHEMT exhibits a high responsivity (λ = 1310 nm) of 1.71 A/W under optimal bias conditions. A -3 dB electrical bandwidth of 400 MHz is produced by the photovoltaic effect and dominated by the long lifetime of the excess holes. The -3 dB electrical bandwidth associated with the photoconductive effect is 2.3 GHz, and is determined mainly by the short electron life time. A power gain cut-off frequency (fmax) of CTG-MHEMT of 18.2 GHz was achieved. This value, is much larger than that of TG-MHEMT (14.6 GHz) because Au nano particles improved the gate resistance. The optoelectronic mixing efficiency was enhanced by tuning the gate bias conditions. The CTG-MHEMT optoelectronic mixer is a cost-effective device, and based on the optical and electrical characteristics, is a promising candidate for simplifying the system architecture in fiber-optic microwave transmission applications.

Design and analysis of In 0.53Ga 0.47As/InP symmetric gain optoelectronic mixers

A symmetric gain optoelectronic mixer based on an indium gallium arsenide (In 0.53Ga 0.47As)/indium phosphide (InP) symmetric heterojunction phototransistor structure is being investigated for chirped-AM laser detection and ranging (LADAR) systems operating in the “eye-safe” 1.55 μm wavelength range. Signal processing of a chirped-AM LADAR system is simplified if the photodetector in the receiver is used as an optoelectronic mixer (OEM). Adding gain to the OEM allows the following transimpedance amplifier’s gain to be reduced, increasing bandwidth and improving the system’s noise performance. A symmetric gain optoelectronic mixer based on a symmetric phototransistor structure using an indium gallium arsenide narrow bandgap base and indium phosphide emitter/collector layers is proposed. The devices are simulated with the Synopsis TCAD Sentaurus tools. The effects of base–emitter interface layers, base thickness and the doping densities of the base and emitters on the device performance are investigated. AC and DC simulation results are compared with a device model. Improved responsivity and lower dark current are predicted for the optimized InGaAs/InP device over previously reported devices with indium aluminum arsenide emitter/collector layers.

High-Power High-Responsivity Modified Uni-Traveling-Carrier Photodiode Used as V-Band Optoelectronic Mixers

A modified uni-traveling-carrier photodiode-based V-band optoelectronic mixer is demonstrated. The relative optical local oscillator (LO) and optical intermediate frequency (IF) signal levels and the reverse bias can be optimized for maximum up-converted power. It was found that the optimum optical IF percentage relative to the total incident optical power was approximately 1/3 for all photocurrent levels while the optimum reverse bias increased linearly with photocurrent. A simple analytical model that explains these observations is developed. A high up-converted power of -4.7 dBm was achieved at 60 GHz and photocurrent of 70 mA. The maximum up-converted power is primarily limited by the saturation characteristic of the photodiode.

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).

CMOS Avalanche Photodiode Embedded in a Phase-Shift Laser Rangefinder

This paper presents the design and the characterization of a CMOS avalanche photodiode (APD) working as an optoelectronic mixer. The P+N photodiode has been implemented in a commercial 0.35-mum CMOS technology after optimization with SILVACO. The surface of the active region is 3.78 middot10-3 cm2. An efficient guard-ring structure has been created using the lateral diffusion of two n-well regions separated by a gap of 1.2 mum. When biased at -2 V, the best responsitivity Slambda APD = 0.11 A/W is obtained at lambda = 500 nm. This value can easily be improved by using an antireflection coating. At lambda = 472 nm, the internal gain is about 75 at -6 V and 157 at -7 V. When biased at -6 V, the APD achieves a dark current of 128 muA middotmm-2 and an excess noise factor F = 20. Then, the APD is successfully used as an optoelectronic mixer to improve the signal-to-noise ratio of a low-voltage embedded phase-shift laser rangefinder.