Optoelectronic Mixer Research Articles

Self-Oscillating Harmonic Opto-Electronic Mixer Based on a CMOS-Compatible Avalanche Photodetector for Fiber-Fed 60-GHz Self-Heterodyne Systems

A self-oscillating harmonic opto-electronic mixer based on a CMOS-compatible avalanche photodetector for fiber-fed 60-GHz self-heterodyne systems is demonstrated. The mixer is composed of an avalanche photodetector fabricated with 0.18-mum standard CMOS process and an electrical feedback loop for self oscillation. It simultaneously performs photodetection and frequency up-conversion of photodetected signals into the second harmonic self-oscillation frequency band. The avalanche photodetector and the mixer are characterized and analyzed, and the RF avalanche multiplication factor is investigated. In addition, conversion efficiency as well as internal conversion gain is determined, and bias conditions are optimized for the best self-oscillating harmonic opto-electronic mixer performance. Data transmission of 5-MS/s 32 quadrature amplitude modulation signals using self-oscillating harmonic opto-electronic mixer is successfully demonstrated.

Near-Ballistic Uni-Traveling-Carrier Photodiode- Based V-Band Optoelectronic Mixers With Internal Up-Conversion-Gain, Wide Modulation Bandwidth, and Very High Operation Current Performance

We construct a high-performance optoelectronic mixer by integrating a near-ballistic uni-traveling-carrier photodiode with a V-band (50-75 GHz) coplanar-waveguide-based bandpass filter. The demonstrated device shows an improvement in the V-band output radio-frequency (RF) power and conversion loss of around 3 and 10 dB, respectively, over that of the control device, which does not have such an integrated filter. The strong nonlinearity of the ballistic-transport of the electrons in the active device, and the excellent RF performance of the integrated filter help us to achieve an internal-conversion gain of around 1 dB, from the low to very high optical injected local-oscillator power (20.6 dBm), which corresponds to an approximately 17-mA high-output photocurrent, and very wide up-conversion bandwidth (>15 GHz) at the V-band.

Integrated Heterojunction Bipolar Transistor Optically Injection-Locked Self-Oscillating Opto-Electronic Mixers for Bi-Directional Fiber-Fed Wireless Applications

A 30-GHz-band third harmonic optically injection-locked self-oscillating opto-electronic mixer is implemented with a 10-GHz InP heterojunction bipolar transistor monolithic microwave integrated circuit oscillator. The monolithic self-oscillating mixer can be optically injection locked in wide operating conditions and can perform efficient frequency up- and down-conversion with low-power optical local-oscillator signals. Using the mixer, bi-directional transmission of 32 quadrature amplitude modulation data in a 30-GHz fiber-fed wireless link is successfully demonstrated.

Characteristics of InP–InGaAs HPT-Based Optically Injection-Locked Self-Oscillating Optoelectronic Mixers and Their Influence on Radio-Over-Fiber System Performance

A 30-GHz optically injection-locked self-oscillating optoelectronic mixer (OIL-SOM) is implemented with a high-performance InP-InGaAs heterojunction phototransistor. The subharmonic conversion efficiency and phase noise characteristics of OIL-SOM are investigated and used for analyzing OIL-SOM-based 60-GHz radio-over-fiber downlink data transmission performance. The OIL-SOM characteristics provide lower and upper boundaries for the input optical local oscillation (LO) power range within which the link performance does not significantly depend on input optical LO power

Fibre-supported 60 GHz self-heterodyne systems based on CMOS-compatible harmonic optoelectronic mixers

Fibre-supported 60 GHz self-heterodyne systems using harmonic optoelectronic mixers fabricated with the 0.18 µm standard CMOS technology are demonstrated. Down-link data transmission of 25 Mbit/s, 32 quadrature-amplitude modulation signals in 60 GHz band is successfully performed.

Optoelectronic Mixing Phototransistor for Ultrawide-Band Fiber-Radio Systems

In this study we developed a phototransistor from a pseudomorphic high-electron-mobility transistor (pHEMT) for ultrawide-band fiber-radio communications. The phototransistor can be used not only as a photodetector for absorbing optical signals, but also as an optoelectronic mixer for up-converting intermediate frequency (IF) signals into radio carrier signals. Experimental results show that the proposed phototransistor can provide good mixing performance for the lightwave and microwave signals. It can also simplify the internal structure of a radio access unit (RAU) for ultrawide-band (UWB) fiber-radio systems.

Avalanche-photodiode-based heterodyne optical head of a phase-shift laser range finder

A heterodyne optical head of a phase-shift laser range finder has been developed to measure distances with high accuracy. To increase the signal-to-noise ratio of the photoelectric current, an avalanche photodiode (APD) working as an optoelectronic mixer was used. A new behavioral model is proposed to describe the optical head in order to evaluate its performance according to the background light intensity. When the APD is biased with a dc current source, it is then demonstrated that the signal-to-noise ratio of the signal at the intermediate frequency, as well as the conversion gain, is inversely proportional to the average primary photoelectric current, i.e., to the background light collected by the APD. Yet, the performance obtained can be improved by using an optical filter. Furthermore, the background light also introduces a phase-shift error, which is evaluated so as to estimate the distance error.

Timing noise measurement of 320 GHz optical pulses using an improved optoelectronic harmonic mixer

An improved optoelectronic harmonic mixer (OEHM) has been employed for measuring the timing noise of 320 GHz optical pulses that are generated from a 160 GHz mode-locked laser diode by the temporal Talbot effect. The OEHM makes use of a low-drive voltage LiNbO3 modulator and a W-band unitraveling carrier photodiode for converting the 320 GHz pulse intensity into a low-frequency electrical signal. The time domain demodulation technique has been used for the precise evaluation of phase noise power spectral density. The rms timing jitter has been estimated to be 311 fs for the 10 Hz-18.6 MHz bandwidth.

60-GHz bidirectional radio-on-fiber links based on InP-InGaAs HPT optoelectronic mixers

We demonstrate 60-GHz band bidirectional radio-on-fiber (RoF) links based on InP-InGaAs heterojunction phototransistor (HPT) optoelectronic mixers. They employ remote up/down conversion scheme with optical local oscillator signals distributed from the central office and intermediate frequency (IF) fiber transmission for both up- and down-links. Since frequency up/down conversions and photodetection are carried out by a single HPT optoelectronic mixer, base station architecture is greatly simplified. In order to validate its feasibility, both up- and down-link RoF transmissions of 16 quadrature amplitude modulator data are successfully demonstrated at 60-GHz band using 1.25-GHz IF for down-link and 2.0-GHz IF for up-link.

Optically injection-locked self-oscillating optoelectronic mixers based on InP-InGaAs HPTs for radio-on-fiber applications

We demonstrate an optically injection-locked self-oscillating optoelectronic mixer (OIL-SOM) for radio-on-fiber downlink applications. OIL-SOM is based on a monolithic oscillator containing an InP-InGaAs heterojunction phototransistor (HPT). The oscillator is OIL by remotely delivered optical local oscillator (LO) signals, and provides low phase-noise and high-power electrical LO signals. In addition, the HPT in this oscillator can simultaneously perform optoelectronic mixing, in which optically transmitted intermediate frequency signals are up-converted to the desired radio-frequency band with high conversion efficiency. With these, OIL-SOM can make base station architecture simple in radio-on-fiber downlink systems.

Characterization of a 1/spl times/32 element metal-semiconductor-metal optoelectronic mixer array for FM/cw LADAR

We characterize a 1/spl times/32 element metal-semiconductor-metal photodetector (MSM-PD) array utilized for optoelectronic mixing in an incoherent, amplitude-modulated laser detection and ranging (LADAR) system. The MSM-PDs that make up the one-dimensional array internally detect and down-convert light signals that are amplitude modulated at ultrahigh frequency (UHF). Range information is contained in the low-frequency mixing product derived by mixing a reference UHF chirp with a detected, time-delayed UHF chirp. When utilized in the LADAR system, the MSM-PDs eliminate the need for wideband transimpedance amplifiers in the LADAR receiver. This, in turn, reduces both the cost and complexity of the system. The breadboard LADAR architecture and components are described, and fundamental measurements and imagery taken from the LADAR, using these unique MSM-PDs, are also presented.

Phototransistors based on InP HEMTs and their applications to millimeter-wave radio-on-fiber systems

Phototransistors based on InP high electron-mobility transistors (HEMTs) are investigated for millimeter-wave radio-on-fiber system applications. By clarifying the photodetection mechanism in InP HEMTs, the phototransistor internal gain is determined. We present their use as millimeter-wave harmonic optoelectronic mixers and characterize them at the 60-GHz band. In order to evaluate the InP HEMT optoelectronic mixer performance, internal conversion gain is introduced and a maximum of 17 dB is obtained for 60-GHz harmonic optoelectronic up-conversion. Utilizing them, we construct a 60-GHz radio-on-fiber system and demonstrate 622-Mb/s data transmission over 30-km single-mode fiber and 3-m free space at 60-GHz band.

Kinetic Inductive Model of a Millimeter-Wave High-Temperature Superconducting Optoelectronic Mixer

We introduce and analyze an optoelectronic mixer (OEM) based on the kinetic inductive photoresponse in high-temperature superconducting (HTS) films. This device combines photodetection and optoelectronic mixing functions through a nonlinear change in the kinetic inductance of the HTS film when it is irradiated by an optically modulated microwave signal. A comprehensive theoretical analysis is presented using the two-temperature model to describe the nonbolometric (quantum) photoresponse and the kinetic inductance model for the electrical part. Upon the optical irradiation, the change in the electron temperature of the HTS film leads to a parametric change in the kinetic inductance of the photoexcited HTS bridge, which in the presence of a bias current produces a periodic voltage waveform. In order to obtain the temporal behavior and the frequency content of the output voltage in terms of the input local oscillator and modulation frequencies, the kinetic inductance model and Fourier series analysis have been used and their physical consequences have been discussed in detail. The merit characteristics of the kinetic inductive HTS-OEM, such as intrinsic and optical conversion gains and noise temperature, are evaluated and compared with other high-frequency mixers. This is followed by the numerical simulation of the proposed device.

High frequency scanning response of an APD photocurrent for laser range finder

In this paper, the scanning response of the photocurrent emitted by a large area avalanche photodiode (APD) is studied for a 3D laser camera. This 3D camera is based on a phase-shift laser range-finder to measure distance from 1 to 20 m. To obtain a large field of view of the optical head, a large area APD working as an optoelectronic mixer is used. Photocurrent response versus light spot position above the APD active area is analysed for high frequency measurements. Optoelectronic mixing permits to measure the scanning response phase of the internal photoelectric current. Moreover, it is demonstrated that the signal phase depends on the photoelectric gain. Signal-to-noise ratio and distance measurement error for the 3D camera are then discussed.

Analysis of the mixing effect in InAlAs/InGaAs metal‐semiconductor‐metal photodetectors

AbstractThe optoelectronic mixing effect in InAlAs Schottky‐enhanced InGaAs‐based metal‐semiconductor‐metal photodetectors (MSM‐PDs) is analyzed. The measured frequency bandwidth of the optoelectronic mixer (OEM) is less than that of a corresponding photodetector. The mixing efficiency depends on the light‐modulation, local‐oscillator, and mixed‐signal frequencies and decreases nonlinearly with a decrease in optical power. We present a circuit model of the OEM to explain the experimental results. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 108–112, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11141

Analysis of an avalanche photodiode used as an optoelectronic mixer for a frequency modulated continuous wave laser range finder

A heterodyne photodetection method is proposed in order to improve the signal to noise ratio of a frequency-modulated-continuous-wave- (FMCW-) like laser range finder. For this purpose, the non-linearity of the current–voltage characteristic of an avalanche photodiode (APD) is used. The photoelectric current is mixed with a local oscillator (LO) signal inside the APD working as an optoelectronic mixer. The signal from the LO can be injected inside the APD by an optical or an electrical channel, both techniques being compared in this paper. A model of the APD taking into account the thermal effects is then proposed. It is demonstrated that the conversion efficiency of the optoelectronic mixer reaches 0.5 in quasi-darkness conditions. Experimental results are in agreement with the theoretical analysis. The feasibility of an FMCW laser range finder using an APD as an optoelectronic mixer is then shown.

Ultrahigh-power-bandwidth product and nonlinear photoconductance performances of low-temperature-grown GaAs-based metal-semiconductor-metal traveling-wave photodetectors

Maximum-output-power and bandwidth performances are usually two tradeoff parameters in the design of high-speed photodetectors (PDs). In this paper, we report record high-peak output voltage (/spl sim/ 30 V) together with ultrahigh-speed performance (1.8 ps, 190 GHz) observed in low-temperature-grown GaAs (LTG-GaAs)-based metal-semiconductor-metal (MSM) traveling-wave photodetectors (TWPDs) at a wavelength of 800 nm. Ultrahigh-peak output power and ultrahigh-electrical bandwidth performances were achieved due to superior MSM microwave guiding structure, short carrier trapping time, and the capability to take high bias voltage (/spl sim/ 30 V) with a LTG-GaAs layer. Under such a high bias voltage, a significant nonlinear photocurrent increase with the bias voltage was observed. The nonlinear photoconductance and ultrahigh-output power-bandwidth performances opens a new way in the application of high-performance optoelectronic mixers and photomixer devices.

Improvement of the FMCW laser range-finder by an APD working as an optoelectronic mixer

A laser range-finder has been designed for distances from 1 to 20 m with diffusing targets. The measurement principle using a frequency modulation continuous wave technique is first described. Improvement for short distance measurements is then proposed with a new set-up using a delay line and an avalanche photodiode working as an optoelectronic mixer used to obtain a wide-band and a low-noise photoreception.

Theoretical analysis of an anisotropic metal–semiconductor–metal optoelectronic mixer

We present a detailed study of the optoelectronic mixing effect in metal–semiconductor–metal detectors. Both analytical and numerical results are presented and the anisotropic effect is included in the calculations. Under transient bias voltage, the device shows two transient current responses: a fast one related to the displacement current and a slow one related to removal of carriers from the device. The mixing efficiency of the device increases with an increase in applied ac voltage and decreases with an increase in ac frequency. For anisotropic devices, rectification current exists. This rectification current varies not only with the ac voltage and optical power, but also with the ac frequency. This variation in current results in a self-clutter signal being observed in the experiments.

60-GHz optoelectronic image rejection mixer and its application to a 156-Mb/s fiber-optic mm-wave link

This letter reports on the first implementation of an optoelectronic image rejection mixer having a finite bandwidth without using an electrical phase control or filtering of millimeter-wave signals and on its first application to fiber-optic millimeter-wave (mm-wave) transmission. An image rejection ratio of >20 dB was confirmed over a 400-MHz bandwidth for an IF frequency of 2 GHz. In addition, fiber-optic transmission of 156-Mb/s ASK 60-GHz optical mm-wave signal over a 20-km standard single mode fiber was successfully demonstrated with a bit error rate of 10/sup -9/ or lower.