Positive-intrinsic-negative Photodiode Research Articles

Quadrature amplitude modulation frequency up- and down-conversions using a positive-intrinsic-negative photodiode sampling mixer

Simulation and experimental performance analysis of a positive-intrinsic-negative photodiode (PIN-PD) sampling mixer used as frequency up and down-converters are presented. Besides, a frequency mixing with a PIN-PD can operate in a frequency range up to 47.3 GHz for up-conversion and 38.5 GHz for down-conversion. The design and operating regime peculiarities of a PIN-PD as an up and down-converter in a radio over fiber (RoF) system are also discussed. The conversion gain of a PIN-PD sampling mixer is simulated and measured. We showed that the gain may decrease from 27 dB at a mixing frequency of 8.3 GHz to 3 dB at the one with 47.3 GHz in an up-conversion mode and from 26.5 dB at 31.7 GHz to 7 dB at 38.5 GHz in a down-conversion mode, when the PIN-PD bias voltage was 0 V. The conversion gain degrades with the decrease of the bias voltage from 0 to −5 V. Error vector magnitudes (EVMs) of the quadratic amplitude modulation (M-QAM) up and down-converted signals are investigated. Quadrature phase shift keying (QPSK) data at bit rates between 312.5 Mbit / s and 5 Gbit / s are frequency-converted. The EVM is used a performance index to assess the mixing system. Exploitable EVMs in the range of 15% up to 34.9% are reached for up-conversion of the mixing frequency. For down-conversion, the EVM varies from 20% to 34.9% at 5 Gbit / s over the whole frequency range. The EVM of mixed signals is improved with 16-QAM and 64-QAM modulations.

Laser-induced damage in a silicon-based photodiode by MHz picosecond laser

Study of the damage characteristics of silicon-based photodetectors is of great significance in improving application performance, but few studies of laser-induced damage have been undertaken on photodetectors irradiated by hundred-ps fiber lasers. In this work, we demonstrate an all-fiber ps-pulsed laser system which outputs a pulse width of 226.5 ps and an average power of 20 W at 2.4 MHz repetition rate, with high beam quality and pulse stability. Experiments use this fiber amplifier to irradiate a silicon-based positive–intrinsic–negative (PIN) photodiode. The changes in detector performance and surface morphology are confirmed by systematic experiments on the laser-irradiated detector. The results show that detection performance was sensitive to laser energy, and the failure damage threshold was about 864 kW cm−2. Based on hydrodynamics theory, we simulated the laser-induced plasma density distribution in a PIN photodiode and studied the thermal and plasma damage mechanisms in the PIN photodiode.

Numerical simulation of millisecond laser-induced output current in silicon-based positive-intrinsic-negative photodiode

Based on the photoelectric effect, the output current model of the silicon-based positive-intrinsic-negative (PIN) photodiode irradiated by millisecond pulse laser was established; the time distribution of the output current on the PIN photodiode under different bias voltages, energy densities, and pulse widths were calculated. The results showed that: the output current process of PIN photodiode irradiated by millisecond laser could be divided into three stages: photo-generated current stage, conduction stage and recovery stage; at the photo-generated current stage, the peak value of output current increased with the increase of energy density and bias voltage; at the conduction stage, with the increase of energy density the value of output current remained the same while increased with the increase of bias voltage; at the recovery stage, with the increase of bias voltage the value of recovery time remained the same while increased with the increase of energy density. In this paper, the simulation results were consistent with the experiment results.

Effect of strong atmospheric non-Kolmogorov turbulence on the M-ary PSK subcarrier intensity modulated free space optical communications system performance.

Atmospheric turbulence is one of the significant phenomena that degrades the free space optical (FSO) communications system performance, and thus designers need to define the requirements related to turbulence and optimize the system design to ensure optimum performance. The subcarrier intensity modulation (SIM) shows superiority in terms of bandwidth usage over the other modulation techniques. Performance of FSO communication systems exercising M-ary phase-shift-keying (PSK) SIM with the PIN photodiode receiver is evaluated in non-Kolmogorov strong atmospheric turbulence when a Gaussian beam is used as the excitation. Bit-error-rate (BER) of PSK SIM FSO communication systems is examined, and the results are presented versus the non-Kolmogorov atmospheric turbulence and positive-intrinsic-negative (PIN) photodetector parameters such as PIN photodetector responsivity, equivalent load resistor, modulation order, noise factor, bandwidth, propagation distance, and beam source size.

Frequency equivalent circuits for the on and off state of an optically triggered switch based on a PIN photodiode

In this work we have developed equivalent circuit models for the frequency response of an optically triggered switch based on a positive-intrinsic-negative photodiode (PIN-PD) for the On state (light applied to the PIN-PD) and the Off state (without applying light to the PIN-PD). From measurements it was found the frequency response in Off state behaves as a high-pass filter whereas in the On state as a low-pass filter; this means that depending on the input signal frequency there could be an approach or even an overlap between the output amplitude in the On and in the Off state. The developed models allow the calculation of the highest permissible frequency in the input signal to avoid distortion due to overlap of the On and Off state response, and the models take into account circuit parameters such as bias voltage, load resistance, resistance, and capacitance of PIN-PD, which in turn depend on the operating point and the desired linear range for the input's amplitude. Experimental measurements of the frequency response were made in both conditions (On and Off state) using three commercial photodiodes of bandwidth higher than 1 GHz. The measured frequency response as well as amplitude separation between the On and Off states to avoid the overlap is very well matched by the calculated results. Although the tests were performed for photodiodes with 1 GHz bandwidth, the technique can be applied for photodiodes with higher bandwidth.

Structural, optical and electrical behavior of millisecond pulse laser damaged silicon-based positive-intrinsic-negative photodiode

In this work, laser induced optical, electrical parameter degradation and morphological damage have been observed in silicon-based positive-intrinsic-negative (PIN) photodiode. Temperature evolution, surface morphology, damaged area and responsivity are monitored for permanent laser induced change. The 1064nm laser pulses are reported for values of pulse length τ ranging from 1ms to 3ms. The loss of responsivity is corresponding to the temperature and damaged area increased on the upper surface, with the increase of laser fluence, the damaged area is increased, resulting in an increase in decline proportion of responsivity. The damage behavior indicated that the millisecond laser-induced electrical and optical parameter degradation in silicon-based PIN photodiode mainly contributed to the removal of the Si3N4 coating destroyed, redistribution of dopant and the introduction of defects.

Visible light communications using predistortion signal to enhance the response of passive optical receiver

Traditional visible light communication (VLC) uses positive-intrinsic-negative photodiode (PD) or avalanche PD as the optical receivers (Rx). We demonstrate using a solar cell as the VLC Rx. The solar cell is flexible and low cost and converts the optical signal into an electrical signal directly without the need of external power supply. In addition to acting as the VLC passive Rx, the converted electrical signal from the solar cell can charge up the battery of the Rx nodes. Hence, the proposed scheme can be a promising candidate for the future Internet of Things network. However, a solar cell acting as a VLC Rx is very challenging, since the response of the solar cell is limited. Here, we propose and demonstrate using predistortion to significantly enhance the solar cell Rx response for the first time up to the authors’ knowledge. Experimental results show that the response of the solar cell Rx is significantly enhanced; and the original 2-kHz detection bandwidth of the solar cell can be enhanced by 250 times for receiving 500-kbit/s VLC signal at a transmission distance of 1 m. The operation principle, the generated voltage by the solar cell, and the maximum data rates achieved at different transmission distances are also studied.

A novel PIN photodetector with double linear arrays for rainfall prediction**Project supported by the National Natural Science Foundation of China (No. 61434001) and the ‘Thousands Talents’ Program for Pioneer Researchers and Its Innovation Team, China.

A novel PIN (positive–intrinsic–negative) photodetector with double linear arrays that can be used to measure the diameter of precipitation particles and the space between two droplets in clouds is proposed. The sensitive unit is the PIN photodiode. The chip with a size of 10 × 8 mm2 has 128 photodiodes, and each row has 64 photodiodes. The device design, fabrication process and package are introduced in the paper. The photocurrent of the packaged chip was systematically tested with a red laser. Also the diameter of one water drop and the space between two water drops were measured. The minimum raindrop diameter which can be tested in this paper is 100 μm. This device can be useful for rainfall prediction.

EFFECTS OF ELECTROMAGNETIC DISTURBANCE ON LIGHT INTENSITY SIGNAL OF LASER BEAM SYSTEM

In performing the experiments, the interference source has the form of a hollow PVC tube wrapped with a current-carrying coil, while the detector has the form of a PIN (Positive-Intrinsic- Negative) photodiode. The experimental results show that the electromagnetic disturbance (EMD) signal effect is dependent on the number of turns, the direction of the electromagnetic field, and the frequency and amplitude of the interference voltage. Specifically, it is shown that when the electromagnetic field acts in the opposite direction to that of the laser beam, the intensity and optical power of the detected signal decrease with an increasing interference frequency or amplitude. By contrast, when the electromagnetic field acts in the same direction as that of the laser beam, the intensity and optical power increase with an increasing interference frequency or amplitude. In addition, it is shown that the effect of EMD on the intensity of the laser beam increases with an increasing laser beam dispersion (i.e., an increasing distance from the laser source).

Frequency spurious aversion by minimal reverse bias selection of a high-speed optically triggered sampling circuit based on a positive–intrinsic–negative photodiode

In this paper we present a procedure for the selection of the minimal dc reverse bias voltage of a high-speed optically triggered sampling circuit. The optically triggered sampling circuit is based on a PIN photodiode. A set of expressions that includes the optical power dependence of the current passing through the PIN photodiode is derived. Theoretical results of the procedure are experimentally verified with practical measurements obtained from a 3 giga samples per second (GS/s) and a 20 GS/s sampling circuit implemented with commercial PIN photodiodes. Reductions in the signal-to-noise and distortion ratio of 37.28 and 6.9 dBs, as well as increments in the spurious free dynamic range of 31 and 19 dBs in the sampled signals, are respectively averted by the selection of the minimal reverse bias.

A photodiode amplifier system for pulse-by-pulse intensity measurement of an x-ray free electron laser

We have developed a single-shot intensity-measurement system using a silicon positive-intrinsic-negative (PIN) photodiode for x-ray pulses from an x-ray free electron laser. A wide dynamic range (10(3)-10(11) photons/pulse) and long distance signal transmission (>100 m) were required for this measurement system. For this purpose, we developed charge-sensitive and shaping amplifiers, which can process charge pulses with a wide dynamic range and variable durations (ns-μs) and charge levels (pC-μC). Output signals from the amplifiers were transmitted to a data acquisition system through a long cable in the form of a differential signal. The x-ray pulse intensities were calculated from the peak values of the signals by a waveform fitting procedure. This system can measure 10(3)-10(9) photons/pulse of ~10 keV x-rays by direct irradiation of a silicon PIN photodiode, and from 10(7)-10(11) photons/pulse by detecting the x-rays scattered by a diamond film using the silicon PIN photodiode. This system gives a relative accuracy of ~10(-3) with a proper gain setting of the amplifiers for each measurement. Using this system, we succeeded in detecting weak light at the developmental phase of the light source, as well as intense light during lasing of the x-ray free electron laser.