Pj Williams

Widely tunable DS-DBR laser with monolithically integrated SOA: design and performance

We report recent device characterization results for a fully packaged widely tunable digital supermode (DS) distributed Bragg reflector (DBR) laser which has been monolithically integrated with a semiconductor optical amplifier. This new device gives all of the wide tunability and high side-mode suppression ratio performance previously reported for the DS-DBR laser with the added feature of output powers in excess of 14 dBm in fiber. In addition to output power and basic tuning behavior, we report on linewidth and relative intensity noise measurements for this device in order to investigate the noise characteristics of this laser.

InP-Based Integrated Optical Pulse Shaper: Demonstration of Chirp Compensation

We demonstrate dispersion compensation for highly chirped optical pulses with an ultracompact optical pulse shaper. The device integrates a 20-channel arrayed waveguide grating with 20 phase modulators and 20 semiconductor optical amplifiers on a single chip of 6 × 6 mm2. The chip has been realized in an InP-based generic photonic foundry process, which enables a significant reduction in design effort using standardized building blocks.

A novel broadband DBR laser for DWDM networks with simplified quasi-digital wavelength selection

A surface ridge DBR laser has been fabricated using conventional InP processing techniques, with the Bragg gratings defined by e-beam lithography. For a phase grating comb spacing of 6.8 nm, a nine grating device is predicted to yield complete coverage over >45 nm, sufficient to cover C- or L-band.

Dynamic control of wavelength switching and shuttering operations in a broadband tunable DS-DBR laser module

Dynamic control of channel switching is demonstrated in a DS-DBR laser module using an integrated optical amplifier as a shutter. Switching time between locked channels is less than 6 ms and frequency deviation less than 5 GHz.

Sidelobes in the response of arrayed waveguide gratings caused by polarization rotation

Earlier it was observed that polarization rotation in an AWG built from birefringent waveguides can result in sidelobes in its response. This effect was measured in a polarization sensitive AWG with an orthogonal layout. Now we investigate through detailed simulation whether this effect also exists in polarization desensitised AWGs. It is shown that a dispersion compensated AWG does not suffer from a polarization sidelobe. Alternatively, the AWG can be designed to minimize polarization rotation to suppress the sidelobe.

Monolithic integrated filtered-feedback multi-wavelength laser

A novel multi-wavelength laser monolithically integrated on InP is presented. The device consists of four channels of Fabry-Pérot lasers using two-port multimode interference reflectors (MIRs) and a single mode operation for each channel is realized by the filtered-feedback from arrayed waveguide grating(AWG).

Common shallow ridge waveguide laser-electroabsorption modulator using lateral ion implantation

For the first time, a laser and high-speed modulator are integrated using a common shallow etched ridge waveguide. Ion implantation lateral to the modulator ridge provides electrical isolation suitable for 10 Gb/s long reach, 55 /spl deg/C operation.

Novel lasers using multimode interference reflector

We present a novel laser using multimode interference (MMI) reflectors. By using the MMI reflectors to form the laser cavity, the laser light is available on the chip, which makes the lasers very promising building blocks in photonic integrated circuits (PIC). These lasers are one of the first InP PIC devices fabricated in a generic multi-project wafer run.

Sidelobes caused by polarization rotation in arrayed waveguide gratings

Polarization rotation within an Arrayed Waveguide Grating (AWG) is found to cause sidelobes in the response of the AWG. The devices in which this effect was observed are briefly discussed. Their measured responses are compared to a detailed simulation.

Extending the tuning range of DS-DBR lasers

We report on modified DS-DBR designs with an increased number of supermodes which achieved 61 nm of continuous tuning. Additionally, a modified manufacturing process gave rise to a significantly flattened gain band shape.