A semiconductor laser amplifier is integrated with a sample grating distributed Bragg reflector (SGDBR) laser to act as an external modulator. The fabrication, characterization, and device characteristics of this integrated tunable transmitter are reported. The integrated tunable laser can have up to 75 mm of tuning range and more than 30 dB of side-mode suppression ratio (SMSR). The integrated amplifier can provide at most 8 dB of gain and more than 25 dB of contrast ratio for all the channels. Its RF modulation bandwidth can achieve 1.5 GHz, and the dynamic chirp is as good as a directly modulated laser. A simple model is proposed to explain the measured modulation responses and gain saturation is found to be the main cause of the resonant peaks in the dynamics.

In recent years, there has been continuous interest in developing tunable receivers for wavelength-division multiplexed (WDM) systems. A direct-detection receiver with a combination of an optical preamplifier and an optical filter offers possible high sensitivity and selectivity. In this paper, we report on an InP/InGaAsP widely tunable receiver, which integrates a semiconductor optical amplifier (SOA), a tunable two-stage grating-assisted codirectional coupler (GACC) optical filter, and a waveguide photodetector. The integrated device can be continuously tuned for a 45-nm wavelength range, however, side-lobes are higher than desired. With suitable tapering in the GACC sections, it is predicted that the side-lobes of the integrated device can be depressed to be as low as -50 dB.

The limitations on high-speed data transmission, using widely tunable sampled-grating distributed Bragg reflector (SGDBR) lasers, are investigated. We demonstrate 1.244-Gb/s data transmission over a wavelength range of 45 nm using a single directly modulated tunable SGDBR laser diode. Data transmission was evaluated on four separate wavelength channels each spaced 15 nm apart. Less than 0.6 dB of dispersion penalty was measured on all four channels for transmission over 50 km of standard single-mode optical fiber.

Summary form only given. For some applications in optical communications and spectroscopy, it is desirable to have sources and receivers that can emit or receive a wide range of wavelengths to or from a single waveguide. Although this can be accomplished with large arrays of lasers and detectors, some sort of dispersive combining structure is necessary to provide a single output. For tunable receivers, grating-assisted codirectional coupler (GACC) filters appear to provide the most desirable features. These continuously tunable structures have been integrated with preamplifiers and waveguide detectors to form complete receiver front ends. This paper will present recent experimental sidelobe levels, linewidths and tuning properties of these photonic ICs, and compare them to theoretical expectations.

In this paper, we investigate the effect of interfacial layers on GalnAs(P)/GalnAsP and GalnAs/InP multiple quantum well structures with x-ray diffraction and photoluminescence. We observe a decrease in the room temperature and low temperature photoluminescence intensity as the number of periods is increased which we attribute to the interfaces. Furthermore, different growth interruption schemes show that decomposed As species from TBA have an effect on the structural and optical quality of these structures at both the lower and upper interfaces due to As carry-over. The effect of this carry-over is shown in structural measurements and laser diode results.

The linewidth, chirp and mode-suppression-ratio (MSR) of directly modulated sampled grating DBR (SGDBR) lasers has been measured. Although the tuning range can be up to an order of magnitude larger than in simple DBR lasers (i.e. 60 nm vs 6 nm), we find that the linewidth, chirp and MSR are about the same or better (i.e. (Delta) (nu) < 5 MHz, (alpha) equals 3-8, and MSR > 40 dB) over a wide range of operating parameters. The modulation bandwidth was in excess of 4 GHz, and the dynamic MSR remained > 40 dB as long as the current did not swing below threshold.

The authors demonstrate the first grating-assisted codirectional coupler (GACC) based tunable the InP/InGaAsP materials system. Initial results using reverse bias show a receiver full-width half-maximum of 4 nm and a tuning range of 3 nm. From numerical simulations the authors found the material uniformity played a very important role in the performance of GACC filters.

By using the effects of increasing hydrostatic pressure to counteract the effects of rising temperature, we demonstrate a technique to stabilize the wavelength of an uncooled diode laser. We use the differential thermal expansion between various materials incorporated into the laser package to automatically generate a temperature-dependent pressure, and obtain a 50% reduction in the temperature sensitivity of the wavelength of a 1.55 μm GaInAsP/InP laser.

The modulation bandwidth, dynamic mode suppression ratio, and wavelength chirp of directly modulated sampled grating DBR lasers have been measured, Although the tuning range can be up to an order of magnitude larger than in simple DBR lasers, the chirp is about the same or better over a wide range of operation parameters, The modulation bandwidth was in excess of 4 GHz and the dynamic MSR remained larger than 40 dB as long as the current did not swing below threshold, The linewidth enhancement factor was extracted from the measured. chirp parameters and ranged from three to eight for different lasing wavelengths of the tunable lasers, The dispersion of the linewidth enhancement factor is consistent with published theoretical predictions.

In this paper, we report a widely-tunable receiver which integrates a semiconductor optical amplifier (SOA), a tunable two-stage grating assisted codirectional coupler (GACC) optical filter, and a waveguide photodetector. The integrated device can be continuously tuned for a 45 nm wavelength range.

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.

The authors demonstrate a widely tunable grating-assisted codirectional coupler (GACC) based receiver in the InP/InGaAsP materials system. With current injection of only 20 mA into each filter section, the integrated receiver can be continuously tuned over a 30 nm wavelength range. To the best of the authors' knowledge, this is the highest tuning range reported so far for an InP/InGaAsP GACC tunable receiver.

We have grown high quality InzGa1-zAsyP1-y/InP heterostructure materials and devices in a nonhydride metalorganic chemical vapor deposition (MOCVD) system using liquid group V sources, tertiarybutylarsine (TEA) and tertiarybutylphosphine (TBP) Very low threshold current strained InGaAsP/InP quantum well laser dioders have been grown using TEA and TBP for the first time. Single 90 Angstrom InGaAsP quantum well lasers emitting at 1.55 mu m displayed threshold current densities of 121 A/cm(2) for a 1.6% compressively strained SQW, and 249 A/cm(2) for an unstrained SQW at a cavity length of 3500 mu m. Unstrained ternary (IN0.53Ga0.47As) single quantum well laser diodes exhibited extremely low threshold current densities (Jth=220 A/cm(2)) for broad area devices 3.5 mm in cavity length). To the best of our knowledge, these values are among the lowest reported threshold current density values for 1.55 mu m laser diodes. We have incorporated these QW active regions into InGaAsP/InP sampled grating lasers. We have obtained, for the first time, continuous wave (cw) operation with 62 nm cw tuning range, 10 mW output power, and monotonic tuning in these lasers. In addition, we have also fabricated high speed InGaAs/InP heterojunction junction field effect transistors (HJFETs) which exhibit high maximum frequency operation (f(max)=37.5 GHz) and high current cut-off frequency (f(T)=14.3 GHz). These results indicate that TEA and TBP are viable replacements for the more hazardous compressed gases, arsine and phosphine.

Long-wavelength (1300/1550 nm) vertical-cavity surface-emitting lasers (VCSELs) have been much more difficult to realize than VCSELs at shorter wavelengths such as 850/980 nm. The primary reason for this has been the low refractive index difference and reflectivity associated with lattice-matched InP/InGaAsP mirrors. A solution to this problem is to “wafer-fuse” high-reflectivity GaAs/AlGaAs mirrors to InP/InGaAsP active regions. This process has led to the first room-temperature continuous-wave (CW) 1.54 µm VCSELs. In this paper, we discuss two device geometries which employ wafer-fused mirrors, both of which lead to CW operation. We also discuss fabrication of WDM arrays using long-wavelength VCSELs.

The authors demonstrate the first field-induced guide/antiguide modulators (FIGAMs) on InP-based materials. Good electrical isolation between electrodes was obtained by implanting through the quaternary waveguide and 15 dB on/off ratio has been achieved. Bit error rate measurements for system applications are also reported.<>