Photonic Receiver Research Articles

Single-Sideband Electro-Optical Modulator and Tunable Microwave Photonic Receiver

We report on the study of widely tunable, resonant single-sideband electro-optical modulators based on whispering gallery mode (WGM) resonators, made out of electro-optically active materials. The modulation process involves interaction of different WGM families with an externally applied microwave field. The tunability results from the unequal response of the mode families to either a temperature change or to an applied voltage. We show that the modulator can be used as an efficient microwave photonic receiver that operates either in direct or coherent regime. Due to its resonant nature, the high-Q electro-optical modulator also can be used as a resolution booster for a low-resolution RF spectrum analyzer.

Multi-channel silicon photonic receiver based on ring-resonators

We demonstrated a high performance monolithically integrated multi-channel receiver fabricated on the SOI platform. This receiver is composed of a 1 x 8 Si-based ring-resonators filter and an array of high speed waveguided Ge-on-Si photodetectors. The optical channel spacing is about 1.5 nm. The responsivity of Ge-on-Si photodetector is about 1.0 A/W at the wavelength range of 1554 nm to 1564 nm. Each channel is capable of operating at a data rate of 20 Gbps, resulting in an aggregate data rate of 160 Gbps. At a BER of 1 x 10(-11), the receiver showed an optical input sensitivity of between -20 dBm and -21 dBm for each channel at 10 Gbps data rate.

WDM multi-channel silicon photonic receiver with 320 Gbps data transmission capability

A high performance monolithically integrated WDM receiver is fabricated on the SOI platform, with key components comprising a 1 x 32 Si-based AWG and an array of high speed waveguided Ge-on-Si photodetectors. The optical channel spacing is 200 GHz. This configuration was used to demonstrate 32-channel operation in the L-band, where it is particularly challenging for silicon photonics due to the low absorption coefficient of Ge at L-band wavelengths. Each channel is capable of operating at a data rate of at least 10 Gbps, resulting in an aggregate data rate of 320 Gbps. At a BER of 1 x 10(-11), the WDM receiver showed an optical input sensitivity between -16 dBm and -19 dBm.

High-speed Ge photodetector monolithically integrated with large cross-section silicon-on-insulator waveguide

We demonstrate a compact, high speed Ge photodetector efficiently butt-coupled with a large cross-section silicon-on-insulate (SOI) waveguide in which the Ge p-i-n junction is placed in the horizontal direction to enable very high speed operation. The demonstrated photodetector has an active area of only 0.8×10 μm2, greater than 32 GHz optical bandwidth, and a responsivity of 1.1 A/W at a wavelength of 1550 nm. Very importantly the device can readily be integrated with high performance wavelength-division-multiplexing filters based on large cross-section SOI waveguide to form monolithic integrated silicon photonics receivers for multichannel terabit data transmission applications.

A sub-picojoule-per-bit CMOS photonic receiver for densely integrated systems

We report ultra-low-power (690fJ/bit) operation of an optical receiver consisting of a germanium-silicon waveguide detector intimately integrated with a receiver circuit and embedded in a clocked digital receiver. We show a wall-plug power efficiency of 690microW/Gbps for the photonic receiver made of a 130nm SOI CMOS Ge waveguide detector integrated to a 90nm Si CMOS receiver circuit. The hybrid CMOS photonic receiver achieved a sensitivity of -18.9dBm at 5Gbps for BER of 10(-12). Enabled by a unique low-overhead bias refresh scheme, the receiver operates without the need for DC balanced transmission. Small signal measurements of the CMOS Ge waveguide detector showed a 3dB bandwidth of 10GHz at 1V of reverse bias, indicating that further increases in transmission rate and reductions of energy-per-bit will be possible.

Multiple Frequency Band Microwave Photonic Receiver

The bandwidths of three aperture stacked patch antennas have been combined successfully into a single large bandwidth using microwave photonic techniques. The antenna system produces an effective frequency bandwidth of approximately 150% with an average gain level of 5.5 dBi and gain variation of plusmn2 dB.

${K}_{a}$–Band All-Resonant Photonic Microwave Receiver

We demonstrate a microwave photonic receiver operating at 35-GHz carrier frequency with a sensitivity exceeding ${-}$ 70 dBm in a 3-MHz frequency band and possessing more than 40-dB dynamic range when operated in the direct detection mode. The receiver is based on a lithium niobate optical whispering gallery mode resonator coupled to a microwave strip line resonator. We theoretically analyze the performance of the receiver and estimate its optimal achievable sensitivity and dynamic range.

Suppression of Even-Order Photodiode Nonlinearities in Multioctave Photonic Links

A balanced photonic receiver is demonstrated to suppress photodiode-generated even-order nonlinearities in a photonic link. This result is especially important for multioctave analog applications. Experimental results are presented for a high-frequency (2-30 MHz) link exhibiting 33-dB suppression of the second harmonic, resulting in an output intercept point of 99 dBm due to second-order intermodulation distortion at 26-mA average photocurrent.

Sensitivity of terahertz photonic receivers

We theoretically discuss sensitivity limitations of a THz receiver which is based on up-conversion of the THz radiation into optical domain using high quality factor crystalline whispering gallery mode resonators. We show that the sensitivity of the receiver operating in the nonlinear regime approaches the sensitivity of an ideal THz photon counter. Thermal noise of the counter can be substantially reduced because of transparency of the nonlinear material in the THz frequency range. We also show that the density of power fluctuations of the receiver operating in the linear regime is given by the THz shot noise.

A Compact Photonic Microwave Receiver Integrated with Dielectric Resonator Antenna

A novel structure for antenna-integrated photonic microwave receiver is proposed. The volume of the photonic microwave receiver can be greatly reduced by directly coupling a dielectric resonator antenna to the microdisk-based modulator. Simulation results show good performance for this structure.

Fibre-coupled, single photon detector based on NbN superconducting nanostructures for quantum communications

We present a novel, two-channel, single photon receiver based on two fibre-coupled, NbN, superconducting, single photon detectors (SSPDs). The SSPDs are nanostructured superconducting meanders and are known for ultrafast and efficient detection of visible-to-infrared photons. Coupling between the NbN detector and optical fibre was achieved using a micromechanical photoresist ring placed directly over the SSPD, holding the fibre in place. With this arrangement, we obtained coupling efficiencies up to ∼30%. Our experimental results showed that the best receiver had a near-infrared system quantum efficiency of 0.33% at 4.2 K. The quantum efficiency increased exponentially with the photon energy increase, reaching a few percent level for visible-light photons. The photoresponse pulses of our devices were limited by the meander high kinetic inductance and had the rise and fall times of approximately 250 ps and 5 ns, respectively. The receiver's timing jitter was in the 37 to 58 ps range, approximately 2 to 3 times larger than in our older free-space-coupled SSPDs. We stipulate that this timing jitter is in part due to optical fibre properties. Besides quantum communications, the two-detector arrangement should also find applications in quantum correlation experiments.

40 Gbit/s photonic receivers integrating UTC photodiodes with high- and low-confinement SOAs using quantum well intermixing and MOCVD regrowth

Photonic receivers integrating unitravelling carrier (UTC) photodiodes with high saturation power/high gain semiconductor optical amplifiers (SOAs) are presented. The SOAs demonstrated up to 28 dB of gain with saturation output powers of up to 18.6 dBm, while the UTC photodiodes were capable of 40 Gbit/s operation under high photocurrent operation. The chip-coupled receiver sensitivity was better than −20 dBm at 40 Gbit/s. A high-flexibility quantum well intermixing and MOCVD regrowth integration method was used for device fabrication.

High fill-factor avalanche photodetectors for near-infrared free-space photonic networks

Diffractive optical elements (DOEs) offer the ability to boost fill factors of high-speed (field-of-view limited) near-infrared detectors. In this context, we have investigated the design and fabrication of a system that involves integration of DOEs with avalanche photodetectors (APDs). These APDs are implemented in the antimonide material system for op- eration around a 2.1-mm wavelength. Consequently, such systems could be used to reduce the required threshold power at free-space photonic receivers. To this end, we present the design and fabrication technolo- gies for the DOEs, APDs, and their integration using polymer-based flip- chip interconnections. © 2003 Society of Photo-Optical Instrumentation Engineers.

Analysis of an optical satellite communication system with stabilized microwave reference note transmission

AbstractA new optical satellite communication system with a local oscillator in the transmitter and one in the receiver station is presented. A new microwave–photonic receiver for picking up the stabilized microwave reference note is proposed. The system, which transmits a 2.5‐Gbps FSK signal, is analyzed. Satellite vibration, beam divergence, atmosphere absorption, and scattering are considered. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 149–151, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10260

Semiconductor laser diode optical amplifiers/gates in photonic packet switching

In this paper, we will describe how semiconductor laser diode optical amplifiers/gates can be used in the photonic packet switching systems based on wavelength division multiplexed (WDM) techniques. First, we show that cross-gain modulation (XGM) can be suppressed when the device is used in the transparent condition of the waveguide material even when the input signal power exceeds +18 dBm. We then discuss an appropriate encoding for the optical signal. Experimental results show that high bit rate Manchester-encoding enables the use of semiconductor laser diode optical amplifiers/gates in the gain condition as well as the transparent condition. Finally, a new photonic packet receiver which utilizes a semiconductor laser diode optical amplifier as a packet power equalizer is proposed. This receiver accepts 17 dB power fluctuation at nanosecond speed for 10 Gb/s Manchester-encoded signal.

45 nm wavelength tuning range of an InP/InGaAsP photonic integrated tunable receiver

An integrated widely tunable photonic receiver including a semiconductor optical preamplifier, a two-section grating-assisted co-directional coupler optical filter, and a waveguide photodetector has been produced in the InP/InGaAsP materials system. Although sidelobes and bandwidth are still higher than desired, this integrated receiver can be continuously tuned for a record-wide 45 nm wavelength range.