InP-based Mach-Zehnder Modulator Research Articles

10 Gb/s InP-based Mach-Zehnder modulator for operation at 2 μm wavelengths

We report on the first InP-based Mach-Zehnder modulator (MZM) employing quantum-confined Stark effect (QCSE) for operation around 2000 nm. The polarization sensitive device is based on 15 compressively strained quantum wells and achieves an electro-optic (EO) bandwidth of at least 9 GHz, with a DC extinction ratio of ~9 dB, and a V(π)L ~9.6 V.mm. We demonstrate back-to-back communication with a 10 Gb/s pseudo-random bit sequence (PRBS) of length 2(7)-1 at a wavelength around 2000 nm.

Optical Frequency Comb Block Generation by Using Semiconductor Mach–Zehnder Modulator

A nine-channel optical frequency comb block is successfully generated by using an InP-based Mach-Zehnder modulator. The intensity deviation of the comb block is measured to be 4.9 dB, which agrees with the predicted value by numerical analysis. The wavelength of the comb block can be tuned from 1525 to 1565 nm successfully with constant RF modulation signal amplitude. It is achieved by simply controlling the dc bias applied to the modulator according to the operation wavelength.

Clarification of the Change in the Extinction Characteristics of an InP-Based Mach–Zehnder Modulator

The stability of the extinction characteristics of an InP-based Mach-Zehnder modulator is clarified in detail. The changes in the half-wavelength voltage (Vπ) and null point voltage (Vnull) are investigated under long-term high-temperature aging tests. The time correlations with the change in Vπ and Vnull are different from each other. By using a statistical treatment of the Weibull distribution, the degradation modes of the changes in Vπ and Vnull are clarified as a wear-out failure and an early failure, respectively.

High-Speed, Low-Driving-Voltage Dual-Drive InP-Based Mach-Zehnder Modulator

We present a dual traveling-wave electrode InP-based Mach-Zehnder (MZ) modulator with an n-i-n waveguide structure. An electrical input/output interface placed on one side of the chip helps us to drive the modulator in a push-pull configuration. This configuration provides the modulator with great advantages such as reduced driving voltage amplitude, chirp-free operation, and the ability to support advanced modulation formats. The fabricated modulator exhibits good performance. A 40Gb/s non-return-to-zero (NRZ) signal is successfully generated with a low driving of 1.3Vpp. In addition, a 10-Gb/s optical duobinary (DB) signal is successfully generated and transmitted over a 240-km single-mode fiber (SMF). We also developed a wavelength tunable transmitter hybrid integrated with a modulator with a wavelength tunable laser. Full C-band 10-Gb/s operation and a 100-km SMF transmission with a low power penalty are confirmed.

Demonstration of 10-Gb/s <formula formulatype="inline"> <tex>$C+L$</tex></formula>-Band InP-Based Mach–Zehnder Modulator

We present a 10-Gb/s InP-based Mach-Zehnder modulator with ruthenium (Ru)-doped buried heterostructure waveguides. C- and L -band operation is demonstrated, including transmission over 100 km of single-mode fiber for 1528-1600 nm.

InP-Based Mach–Zehnder Modulator With Capacitively Loaded Traveling-Wave Electrodes

InP-based Mach-Zehnder modulators with capacitively loaded traveling-wave electrodes (CL-TWEs), which have segmented structures along the optical waveguides, are presented. Devices with various structural parameters for gap length (the length between adjacent segmented phase modulators) and total active length were fabricated and investigated both optically and electrically. Excellent characteristics such as characteristic impedance matching to 50 Omega and low electrical propagation losses were obtained. Using the optimum structures, 40- and 10-Gb/s large signal operations were successfully performed with peak-to-peak driving voltages of 3.0 and 1.2 V, respectively. The effects of structural parameters, such as gap length and total active length on electrical and optical modulation properties, are discussed.

Surface Mountable 10-Gb/s InP Mach–Zehnder Modulator Module for SFF Transponder

We have developed a small, surface mountable InP-based Mach-Zehnder modulator module. New designs for the electrical ports enable the modulator to be directly mounted on a printed circuit board. We demonstrated a 100-km transmission through single-mode fiber with a 10-Gb/s nonreturn-to-zero signal and a 220-km transmission with a 10-Gb/s optical duobinary signal to confirm the applicability of this device as an ultralong-haul small form factor transponder.

Wide-wavelength-band (30 nm) 10-Gb/s operation of InP-based Mach-Zehnder modulator with constant driving voltage of 2 V/sub pp/

Wide-wavelength-band operation of InP-based Mach-Zehnder modulators is investigated. From the measured dependences of the half-wavelength voltage on operating wavelength and applied-bias voltage, it is shown that wide-wavelength operation with a constant driving voltage can be realized by adjusting the bias voltage for each operating wavelength. Ten-gigabits/second clear eye openings are demonstrated over a 30-nm wavelength range with a constant driving voltage of 2 V/sub pp/.

Low-chirp 10 Gbit∕s InP-based Mach-Zehnder modulator driven by 1.2 V single electrical signal

A low-chirp and low-driving-voltage InP-based Mach-Zehnder modulator has been developed using capacitively loaded travelling-wave electrodes. A 10 Gbit/s clear eye opening as well as small frequency chirping was successfully obtained using only single electrical signal of 1.2 V peak-to-peak.

Comparison of the propagation performance over standard dispersive fiber between InP-based π-phase-shifted and symmetrical Mach-Zehnder modulators

We estimated and experimentally verified the output phase and intensity characteristics versus the applied voltage of an InP-based Mach-Zehnder modulator from the measured data of refractive index and loss variations specific to the phase section material (Fabry-Perot method). We have then simulated the propagation performance of a Mach-Zehnder modulator taking into account the possible phase-shift between both arm of the interferometer. In total agreement with experimental results, we show that the simple single-arm modulation scheme does not require high voltages and that the /spl pi/-phase-shifted Mach-Zehnder modulator is far more convenient for a 10-Gb/s propagation over standard dispersive fiber than a symmetrical modulator.

10 Gbit/s transmission over 90–127 km in the wavelength range 1530–1560 nm using an InP-based Mach-Zehnder modulator

An InP-based Mach-Zehnder modulator has been realised, and transmission over a standard fibre at 10 Gbit/s over 90-127 km has been successfully demonstrated in a single-arm configuration scheme, in the wavelength range 1530-1560 nm. The sole bias voltage has been adjusted to take into account the wavelength dependence of the electro-optic efficiency of the phase modulator material.