Staffan Björlin

Long-wavelength vertical-cavity lasers and amplifiers

We report on advances in vertical-cavity surface-emitting lasers (VCSELs) and vertical-cavity semiconductor optical amplifiers (VCSOAs) operating at 1.3 and 1.55 /spl mu/m. These devices have the potential to dramatically reduce manufacturing costs compared to traditional in-plane devices, while allowing for the possibility of producing integrated modules and arrays on wafer. A number of different technologies have been proposed and demonstrated for these devices. We discuss the different materials systems used for distributed Bragg reflectors (DBRs) and active regions. Recent designs and results are summarized. Wafer bonded VCSELs and VCSOAs are examined in detail.

Design and analysis of vertical-cavity semiconductor optical amplifiers

The authors present detailed, yet largely analytical, models for gain, optical bandwidth, and saturation power of vertical-cavity semiconductor optical amplifiers (VCSOAs) in reflection and transmission mode. Simple formulas for the gain-bandwidth product are derived. The saturation model considers a sublinear material gain, gain enhancement by the standing-wave effect, and all relevant carrier recombination mechanisms. Excellent agreement with measurements on novel 1.3-/spl mu/m VCSOAs is obtained. The models are used to analyze device performance and to investigate optimization options. Parameter plots are given which allow for an easy exploration of the VCSOA design space, matching desired performance data with the required mirror reflectivity and pump current.

40-Gb/s optical buffer design and simulation

This work proposes a new approach to create optical random access memory for 40-Gb/s optical telecommunications. Results of simulations that investigate the maximum achievable delay are also presented. The design combines silica waveguides for low loss recirculation with InP-based semiconductor devices for high gain and fast switching. This approach provides smaller devices in comparison to fiber-based alternatives and lower loss recirculation than competing material systems.

High-temperature characteristics and tunability of long-wavelength vertical-cavity semiconductor optical amplifiers

In this study, we investigate the high-temperature characteristics and the temperature tuning of long-wavelength vertical-cavity semiconductor optical amplifiers (VCSOA). The temperature shift of the peak-signal gain is shown to depend on the mirror reflectivity of the VCSOA. Experimental results of temperature tuning of a 1.3-/spl mu/m VCSOA are presented. We demonstrate 10 dB of fiber-to-fiber gain over a tuning range of approximately 8 nm.

Optically preamplified receiver at 10, 20, and 40 Gb/s using a 1550-nm vertical-cavity SOA

In this study, we demonstrate optical preamplification at 1550 nm using a vertical-cavity semiconductor optical amplifier (VCSOA). At 10 Gb/s, a receiver sensitivity of -28.5 dBm was achieved for 13 dB of fiber-to-fiber gain. This corresponds to an improvement in the receiver sensitivity of 9.7 dB. We also evaluated the performance at 20 and 40 Gb/s. A 4.7-dB power penalty was measured at 20 Gb/s with 6-dB fiber-to-fiber gain. Theoretical simulations show that the pattern dependence can be mitigated using a VCSOA with lower mirror reflectivity.

High output power 1540-nm vertical-cavity semiconductor optical amplifiers

Vertical-cavity semiconductor optical amplifiers operating at 1540 nm are presented. The use of optically pumped AlInGaAs MQW regions resulted in record-high saturation output power of +0.5 dBm and 17.6 dB of fiber-to-fiber gain.

Wavelength selection in MEMS tunable vertical-cavity SOAs

We analyze the tuning characteristics of MEMS tunable vertical-cavity semiconductor optical amplifiers. Completed devices exhibit 10 dB device gain over an 11 nm tuning range.

1.3 /spl mu/m vertical cavity amplifier

We report the first optically pumped 1.3 micron vertical cavity amplifier with a gain of 13.7 dB in reflection mode. Optimization of the output mirror reflectivity revealed a gain bandwidth of 31 GHz and a saturation power of /spl sim/5 dBm.