Greg A. Fish

Widely tunable sampled grating DBR laser with integrated electroabsorption modulator

We report on the development of the first widely tunable semiconductor laser with an integrated electroabsorption modulator. The laser is a four-section buried-ridge sampled-grating distributed Bragg reflector design. It has a 41-nm continuous tuning range with a maximum tuning current of 23.5 mA for the hack mirror and 21 mA for the front mirror. The modulator is based on a 0.87-eV bandgap bulk waveguide structure. It is capable of producing more than 22 dB of optical extinction over the entire tuning range of the laser with a -4.0-V bias.

Design of sampled grating DBR lasers with integrated semiconductor optical amplifiers

High output powers and wide range quasicontinuous tuning have been achieved in a sampled-grating distributed Bragg reflector laser with an integrated semiconductor-optical-amplifier. Using an amplifier with a curved passive output waveguide to suppress back reflection, we have achieved a quasicontinuous tuning range of over 50 nm and peak output powers greater than +8 dBm. Optimizing the device structure and the sampled-grating mirror design has enabled tuning ranges of up to 72 nm in devices without amplifiers.

Ridge waveguide sampled grating DBR lasers with 22-nm quasi-continuous tuning range

We demonstrate a ridge waveguide sampled-grating distributed-feedback laser with continuous wavelength coverage over a 22-nm tuning range, the largest ever reported for a ridge waveguide structure. The design is based on a 400-nm-thick 1.4-/spl mu/m bandgap waveguide optimized for carrier injection tuning with offset quantum wells used to form the active region. The offset quantum wells enabled the device to be fabricated with only a single metal-organic chemical vapor deposition regrowth step. By tuning both mirror sections and the phase control section we were able to obtain 27 wavelength-division-multiplexed channels spaced at 100 GHz and precisely centered on the ITU grid with equal output power and greater than 40 dB of sidemode suppression ratio.

Highly efficient vertical-cavity surface-emitting lasers optimized for low-temperature operation

Vertical-cavity surface-emitting lasers designed for operation in the temperature range of 77-200 K for cryogenic optical interconnects are reported. Low threshold currents and voltage drops across the mirrors, as well as record high output powers, external efficiencies, and the potential for very high modulation bandwidths are observed.<<ETX>>

40-GHz dual-mode-locked widely tunable sampled-grating DBR laser

Generation of 40-GHz alternate-phase pulses is demonstrated using a dual-mode-locked sampled-grating distributed Bragg reflector laser. More than 10-dB extinction and >20-dB sidemode suppression ratio is measured over the >40-nm tuning range of the laser. Based on captured phase noise spectra, the timing jitter is estimated in the 0.35-0.41-ps range. The demonstrated dual-mode laser would form an attractive basis for an integrated 40-Gb/s return-to-zero transmitter.

Phase noise of widely-tunable SG-DBR laser

The measured phase noise of a widely-tunable SG-DBR laser exhibits white high-frequency noise and low-frequency nonwhite components. The RIN after transmission through fiber indicates that white noise dominantly determines the transmission performance.

Electronic and photonic integrated circuits for fast data center optical circuit switches

This article surveys recent work in optical switching technologies and presents a fast optical circuit switch that intimately integrates the control electrics at the chip level using a novel wafer-scale heterogeneous integration technique.

30-Gb/s Optical Link Combining Heterogeneously Integrated III–V/Si Photonics With 32-nm CMOS Circuits

We present a silicon photonics optical link utilizing heterogeneously integrated photonic devices driven by low-power advanced 32-nm CMOS integrated circuits. The photonic components include a quantum-confined Stark effect electroabsorption modulator and an edge-coupled waveguide photodetector, both made of III-V material wafer bonded on silicon-on-insulator wafers. The photonic devices are wire bonded to the CMOS chips and mounted on a custom PCB card for testing. We demonstrate an error-free operation at data rates up to 30 Gb/s and transmission over 10 km at 25 Gb/s with no measured sensitivity penalty and a timing margin penalty of 0.2 UI.

Transmission of 10 Gbps Duobinary Signals Using an Integrated Laser-Mach Zehnder Modulator

Generation and transmission of 10 Gbps duobinary signals is demonstrated using an integrated widely-tunable SGDBR laser and Mach-Zehnder modulator over a wavelength range of 1538 nm - 1564 nm.

Demonstration of InP-InGaAsP vertical grating-assisted codirectional coupler filters and receivers with tapered coupling coefficient distributions

In this letter, we demonstrate the first vertical grating-assisted codirectional coupler filter and receiver with a tapered coupling coefficient distribution. The tapering is achieved by modulating the grating duty ratio. By doing so, filter responses with sidelobe suppression ratios (SSR) better than conventional devices are observed. Using this design in an integrated receiver, a record SSR of 16 dB is reported. With perfect input coupling, it is found that the receiver sidelobe levels using this approach can be lower than /spl sim/40 dB.