Engelbertus Caspar Maria Pennings

Compact InP‐based ring lasers employing multimode interference couplers and combiners

Multimode interference (MMI) 3 dB couplers and MMI power combiners have been integrated with compact InP/InGaAsP ring lasers (R=150 μm). Radiative loss from the curves is small, and MMI 3 dB couplers are shown to be more efficient than conventional Y junctions. In addition, we demonstrate improved efficiency by combining counterpropagating beams in a single output by means of a MMI combiner. Single mode spectral behavior, with 35 dB side mode suppression, has been measured and is explained as resulting from coupled cavities.

Reflection properties of multimode interference devices

We report on the reflection properties of multimode interference (MMI) devices: we distinguish between reflection back into the input waveguides and internal resonance modes due to the occurrence of simultaneous self-images. Because of self-imaging, reflection can be extremely efficient, even in the case of MMI devices with optimized transmission. This conclusion is confirmed by the observed spectral behavior of InP-based ring lasers incorporating MMI 3 dB couplers and MMI power splitters. Several techniques are proposed to minimize the influence of these reflections.<<ETX>>

Ultracompact multimode interference waveguide devices

Coupling, branching and routing devices are key components for photonic integrated circuits. This paper discusses multimode interference and self-imaging and shows how this effect has created a new class of low-loss, ultracompact and fabrication tolerant routing devices.<<ETX>>

High-gain, high-power 1550-nm polarization independent MQW optical amplifier

A practical 1550-nm polarization independent semiconductor optical amplifier configuration employing compressively strained quantum wells and a few commercially available optical components is reported. Crosstalk from counter propagating light, which may easily occur in such a configuration, has been sufficiently suppressed for practical use. For the entire configuration a net fiber-to-fiber gain of 17 dB, a 3-dB saturation output power of 13 dBm and a noise figure of 9 dB have been demonstrated. The polarization dependence was only 0.7 dB. The polarization independent 1550-nm semiconductor optical amplifier reported here is attractive when power consumption and compactness are of major concern and especially for applications involving nonlinear signal processing and switching.