K. Tsuruoka

1.3-/spl mu/m AlGaInAs strain compensated MQW-buried-heterostructure lasers for uncooled 10-gb/s operation

We have successfully fabricated 1.3-/spl mu/m AlGaInAs strain-compensated multiple-quantum-well (MQW) buried-heterostructure (BH) lasers by narrow-stripe selective metalorganic vapor-phase epitaxy. Based on the optimization of AlGaInAs strain compensated MQW and the Al-oxidation-free BH process, we obtained a low-threshold current of 12.5 mA and a relaxation frequency of more than 10 GHz at 85/spl deg/C for Fabry-Perot lasers. For distributed feedback lasers, we demonstrated a 10-Gb/s operation and transmission of over 16 Km for a single mode fiber at 100/spl deg/C. Furthermore, a record-low 25.8-mA/sub p-p/ modulation current for a 10-Gb/s modulation at 100/spl deg/C was demonstrated with shorter cavity and high grating-coupling coefficient. A median life of more than 1/spl times/10/sup 5/ h at 85/spl deg/C was estimated after an aging test of over 5000 h for these lasers. These superior characteristics at high temperatures were achieved by the combination of the high differential gain of AlGaInAs strain compensated MQW and the BH structure.

10-Gb/s 23-km penalty-free operation of 1310-nm uncooled EML with semi-insulating BH structure

We have developed a 1310-nm uncooled electroabsorption modulator integrated light source (EML) with an AlGaInAs multiple quantum well (MQW) active/absorption stripe, which was simultaneously grown using the narrow-stripe selective MOVPE technique and was buried with an Fe-doped InP. The Al-content MQW oxidation was effectively inhibited by using the same technique. An experiment-based evaluation of the devices performance revealed that by only changing the modulation bias voltage linearly with temperature, it was possible to achieve 10-Gb/s penalty-free operation at up to 85/spl deg/C over a 23-km single-mode fiber.

Transmission Over 360 km Using a 2.5-Gb/s SOA-Modulator Integrated Full

We present an external-cavity wavelength-tunable laser with a semiconductor optical amplifier-modulator monolithically integrated on the gain chip. The modulator chirp is analyzed, and it is explained how the chirp can be partially cancelled by self-phase modulation in the transmission fiber. Full C-band transmission of 2.5-Gb/s data over 360 km is demonstrated with small power penalty

C

Integration of a booster semiconductor optical amplifier (SOA) is an efficient way of overcoming losses in InP based Mach-Zehnder modulators. We analyze the impact of locating the SOA before and after the MZM, respectively, in terms of output power and signal integrity at 10 Gb/s, both experimentally and theoretically. For a device with 10 dB MZM loss it is found that, for a fixed power consumption, locating the SOA after the MZM provides 7-9 dB higher output power. This advantage is reduced for lower MZM losses but remains significant. With the SOA after the MZM, the gain is restricted by dynamic saturation effects (waveform distortion), which is not the case if the SOA is at the input of the MZM. The waveform distortion is accompanied by a spectral red-shift, which degrades the transmission performance. Simulations show that for MZM losses below ~4 dB, locating the SOA before the MZM can provide a higher power with no waveform distortion and negative chirp, at the cost of a higher SOA gain. For higher MZM losses it is unfeasible to locate the SOA before the MZM, due to a prohibitively large power consumption.

-Band Wavelength-Tunable Transmitter

In this paper, high-performance full-band external cavity wavelength-tunable lasers (ECTLs) are detailed. Our approach utilizes an external cavity configuration, which makes use of a liquid-crystal tunable mirror and a wavelength reference etalon. This ECTL module shows a tuning range of 45 nm, fiber-coupled output power of more than 14 dBm with a side-mode suppression ratio better than 59 dB, wavelength accuracy of 0.6 GHz, relative intensity noise better than -150 dB/Hz, and linewidth narrower than 1 MHz.

SOA-Booster Integrated Mach–Zehnder Modulator: Investigation of SOA Position

A gap-mirror technology for integrating a functional section onto a laser gain chip is presented. A semiconductor optical amplifier, implementing several functions, is integrated on the gain chip used in an external cavity laser, and demonstrated as a high-performance variable attenuator and data modulator at 2.5 Gb/s. Control of the mirror properties through the gap geometry is demonstrated, and further optimization is realized by a gap-filling technique, which increases the output power to above 100 mW across the C -band.

Wideband External Cavity Wavelength-Tunable Laser Utilizing a Liquid-Crystal-Based Mirror and an Intracavity Etalon

We have developed a four-channel AlGaInAs multiple quantum well, buried heterostructure, distributed feedback laser diode (MQW BH-DFB-LD) array for 1.3-/spl mu/m coarse wavelength division multiplexing (CWDM) systems. Fine detuning control by using a narrow-stripe selective metalorganic vapor-phase epitaxy (MOVPE) technique and an electron beam (EB) lithography technique enables 10-Gb/s operations in all channels at 85/spl deg/C. We obtained throughputs of more than 40 Gb/s in total. We confirmed low crosstalk operations for a 250-/spl mu/m pitch array. This is an attractive feature for fabricating compact transmitter modules.

Integration of Functional SOA on the Gain Chip of an External Cavity Wavelength Tunable Laser Using Etched Mirror Technology

We propose a widely tunable and low insertion loss loop filter incorporating two ring resonators and an asymmetric Mach-Zehnder interferometer. A semiconductor optical amplifier, phase control section, and loop filter are monolithically integrated on one chip in the InP-InGaAsP material system. The tuning range of 39 nm with side-mode suppression ratio of over 30 dB was demonstrated. The maximum of the total heater power over the tuning range was 84 mW.

Four-channel 10-Gb/s operation of AlGaInAs-MQW-BH-DFB-LD array for 1.3-/spl mu/m CWDM systems

We propose a novel external cavity wavelength tunable laser (ECTL) configuration without an etalon inside the cavity. ECTL consists only of a semiconductor optical amplifier with an integrated phase section, and a liquid crystal tunable mirror. We successfully demonstrated excellent performances of the ECTL with fiber coupled output power of more than 50 mW over a 40-nm tuning range, sidemode suppression ratio of better than 45 dB, relative intensity noise of better than -148 dB/Hz, and linewidth of narrower than 2.3 MHz

A Monolithic Wideband Wavelength-Tunable Laser Diode Integrated With a Ring/MZI Loop Filter

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.