We report the first demonstration of Si microresonators (MRs) fabricated via substrate transfer on a silica waveguide (WG) wafer. Specifically, these Si microdisks were fabricated on a layer of Si (0.16-0.2 μm thick) that was directly-bonded on a silica waveguide wafer. We measured the throughput and drop spectrum of these microdisks when coupled to bonded silica waveguides, and observed loaded quality-factors (Qs) of ≥10(4). We modeled, in addition, the dispersion of whispering gallery modes in these microdisks to show phase-matched coupling with an incident silica waveguide or fiber-taper. Using the measured extinction ratio and loaded-Q, we evaluated, in addition, the coupling coefficient between the incident waveguide/taper and Si MR.

A new RF-photonic transversal filter based on wavelength division multiplexed (WDM) technologies is reported. The tap-amplitudes of the bandpass filter were designed to be antisymmetric and arbitrarily reconfigurable. For 20-tap filters centred at 4.8 GHz, a sidelobe suppression of >30 dB, passband widths <470 MHz, and a linear insertion phase are demonstrated.

A 10.24GSPS photonic sampled DeltaSigma modulator was implemented with HRL laboratories InP HBT process. The 12GHz analog input is sampled by a LiNbO3 optical modulator with a 10.24GHz ultra-low jitter mode-locked laser. The intensity-modulated differential laser pulses are converted into electronic charges by on-chip GaInAs photo diodes and directly integrated into the first stage integrator of a 4th-order continuous-time bandpass DeltaSigma modulator with a passband centered at 1.8GHz. The high notch frequencies of the DeltaSigma ADC are achieved by using a special type of integrator. This ADC achieves 59.9dB SNDR in 1MH bandwidth with 1263 InP HBT transistors

We have developed a conformal optical modulator structure comprising pixellated InGaAs-InAlAs multiple-quantum-well (MQW) electroabsorption modulators embedded in a polymer membrane for operation in the 1550-nm optical region. The MQW modulators retain their electrical and optical characteristics after the polymer embedding process, with leakage currents of less than 50 nA and modulation contrast ratios of 2 : 1. The radio frequency response of these modulators was shown to be dependent on the pixel size, with a 3-dB modulation frequency of over 200 MHz for a 225/spl times/125 /spl mu/m/sup 2/ pixel. The conformal MQW modulator structure developed here can be used in applications requiring placement on a curved surface, such as in cat's eye modulating retroreflectors.

This paper summarizes our recent work on high-speed photonic analog-to-digital conversion (A/D) technologies, where picosecond pulses generated by a 10 GHz mode-locked laser source were used to accomplish low-jitter photonic sampling. In addition, we describe our progress in the generation of 40 GHz wavelength-coded pulses for time-interleaved A/D, and the demonstration of photonic bandpass (at 1.6 GHz) Δ-∑ quantizers clocked at 10 GHz.

This paper compares two approaches for evaluating the amplitude and timing jitters of an Er-fiber laser mode-locked at 10 GHz. Using a low-noise oscillator as the clock drive for the mode-locking, relative amplitude jitter was measured as low as 0.0384% and timing jitter as low as 0.0153% (/spl Delta/f=100 Hz-40 MHz). Applying the mode-locked pulse train in a photonic sampling experiment at 10 Gsample/s, a spurious free dynamic range (SFDR) of /spl sim/48.5 dB (over the Nyquist bandwidth of 5 GHz) for multiple analog inputs at L band (1-2.6 GHz). These results correspond to an analog-to-digital conversion resolution of /spl sim/8 SFDR bits at 10 Gsample/s. Finally, the use of "instantaneous companding" is demonstrated to correct for third-order distortions generated by a Mach-Zehnder modulator used in the photonic sampling link.

The 10GHz modelocking of a fibre laser with timing jitters as low as 16fs (Deltaf = 100Hz - 100kHz) and amplitude jitters of 0.058% is reported. From the spur-free-dynamic-range (SFDR) measured for a signal (at 2.49GHz) sampled with the modelocked pulse train, we estimate an analogue-to-digital conversion resolution of 8 SFDR bits at 10Gsample/s.

We report the 10 GHz mode-locking of a fiber-laser with timing-jitters as low as 16 fs (Δf=100 Hz-100 kHz), and amplitude-jitters of 0.058%. From the spur-free-dynamic-range (SFDR) measured for a signal (at 2.49 GHz) sampled with the mode-locked pulse train, we estimate an analog-to-digital conversion resolution of 8 SFDR-bits at 10 GSPS

Conceptually, picosecond pulses generated by a mode-locked (ML) laser are ideal vehicles that can help achieve accurate impulse sampling of an analog signal. As illustrated an electro-optic modulator can be used to impress the analog input onto the optical pulse train. After photodetection, the received signal due to the modulated pulse train is sent, in turn, to an electronic quantizer for digitization

We report single- and multi-element fibre grating coupled diode laser transmitter modules that emit at ITU-designated wavelengths. In addition, we demonstrate that they can attain a direct modulation bandwidth that is as high as 4.62 GHz. Previously, the highest speed reported for these devices was 3.5 GHz

We describe the design of single frequency array transmitters and their application in RF-photonic systems. In addition, we present an array-based packaging technology that is based on passive-alignment with Si-waferboards.

The design and fabrication of a 1.3- mu m waveguide-coupled strained-layer In/sub x/Ga/sub 1-x/As/GaAs MSM detector with an optimized active layer thickness is reported. For 100- mu m-long devices, a responsivity of 0.58 mA/mW is observed. Using the detector as an optoelectronic switch, on/off ratios better than 40 dB were achieved at L and X band.< >

The authors fabricated and packaged 1*4 arrays of In/sub 0.53/Ga/sub 0.47/As p-i-n photodetectors connected in a GaAs FET bias-switched, common cathode circuit. The bandwidth of the discrete (packaged) photodiodes in the arrays exceeds 11 GHz, and is 5 GHz for the packaged arrays. The on/off isolation ratio for fully packaged arrays using GaAs FET bias switches was measured at both low and high frequencies. It was found that the on/off isolation of the detectors in the array was 70 dB, and the bias switching times were less than 5 ns. The performance characteristics suggest that the p-i-n detector arrays used in a common cathode, current summing configuration have applications for high-freqeuncy digital and analog optical switching applications.< >

An optoelectronic crossbar switch has been fabricated and tested at 100-175 Mbit/s. The optoelectronic switching is achieved using bias switched detectors.<>