Traveling-wave Electroabsorption Modulators Research Articles

40 GHz optical pulse generation using sinusoidally-driven travelling-wave electroabsorption modulator

Optical pulse generation at a 40 GHz repetition rate using a sinusoidally-driven high-modulation-efficiency travelling-wave electroabsorption modulator is reported. Travelling-wave behaviour is demonstrated by comparing the pulse generation in the co- and counter-propagation configurations and confirmed by a theoretical model.

High-saturation high-speed traveling-wave InGaAsP-InP electroabsorption modulator

High-saturation power traveling-wave electroabsorption modulators (TW-EAMs) with modulation bandwidth greater than 40 GHz have been demonstrated. Microwave properties of the TW-EAM waveguide are extracted from the measured S-parameters using an equivalent circuit model. Excellent agreement is obtained between the predicted and the measured frequency responses.

2.3 picoseconds optical gate monolithically integratingphotodiodeandelectroabsorption modulator

A novel ultra-high-speed optical gate monolithically integrating a uni-travelling-carrier photodiode and a travelling-wave electroabsorption modulator (TW-EAM) is presented. By using the nonlinear extinction characteristics of the EAM, the minimum gate opening time of 2.3 picoseconds with an extinction ratio of 14 dB is achieved.

Distributed effects model for cascaded traveling-wave electroabsorption modulator

A distributed model based on the large-signal electrooptic conversion is proposed to analyze cascaded traveling-wave electroabsorption modulators (TWEAMs) for high-speed optical switching applications. The microwave propagation loss, velocity mismatch, as well as frequency chirping are included. The model predicts that a cascaded TWEAM structure has the advantage of a high design tolerance to various distributed effects and an improved extinction ratio and optical loss in comparison to a single device of same total length. The agreement between experimental and calculated results indicates that the cascaded structures can be implemented for efficient TWEAM design.

Velocity-Mismatching Effect on Extinction Characteristics of Traveling Wave Electroabsorption Modulator

The velocity-mismatching effect of the traveling wave electroabsorption modulator (TWEAM) is investigated. A model is proposed to design the length of the modulator. Optical transmission through the device is simulated and the degradation of extinction ratio with velocity mismatch is analyzed.

Integrated tandem traveling-wave electroabsorption modulators for >100 Gbit/s OTDM applications

Integrated tandem traveling-wave electroabsorption modulators are demonstrated as high-speed optical short pulse generators and demultiplexers for >100 Gbit/s optical time-division-multiplexed systems. The tandem significantly increases the extinction ratio and further compresses the optical pulses in comparison to a single modulator. An extinction ratio of /spl sim/50 dB is achieved while optical pulses of 4-6 ps width at 30-40 GHz are generated.

3.7 ps pulse generation at ≥ 30 GHz by dual-driveelectroabsorption modulator

The authors describe optical short pulse generation at frequencies ≥ 30 GHz by a dual-drive scheme of a high-saturation power travelling-wave electroabsorption modulator. Sub-4 ps almost-transform-limited pulses are achieved with > 20 dB dynamic extinction ratio and low polarisation sensitivity.

Simultaneous OTDM demultiplexing and detection using an electroabsorptioa modulator

A traveling-wave electroabsorption modulator is used to simultaneously demultiplex and electrically detect a single 10-Gb/s channel from a 20-Gb/s optical time-division multiplexed data stream while transmitting the other channel in an optically transparent manner. A bit-error-rate penalty of 0.5 dB and an error floor were observed for the dropped channel due to residual absorption of the other channel. Error-free operation was achieved for the transparent channel.

Wide-bandwidth lasers and modulators for RF photonics

In this paper, the basic principle of operation, design issues, limitations, recent developments and emerging research trends on wide-bandwidth lasers and modulators for radio-frequency photonic applications are reviewed. The topics covered are wide-bandwidth lasers, lumped and traveling-wave electroabsorption modulators, traveling-wave LiNbO/sub 3/, GaAs, and polymer modulators.

Ultrahigh-speed traveling-wave electroabsorption modulator-design and analysis

Theoretical analysis and numerical calculations are presented for ultrahigh-speed (>50 GHz) traveling-wave electroabsorption modulators (TW-EAM's), including effects of velocity mismatch, impedance mismatch, and microwave attenuation. A quasi-static equivalent circuit model is used to examine the TW-EAM microwave properties, including the effect of photocurrent. Due to the optical propagation loss of the waveguide, the TW-EAM waveguide length for maximum RF link gain is currently limited to 200-300 /spl mu/m. The discussion indicates that the carrier transit time in the intrinsic layer may not severely limit the TW-EAM bandwidth. Three TW-EAM design approaches are discussed: low-impedance matching; reducing the waveguide capacitance; and distributing the modulation region.