Yasuhiro Hinokuma

High-Power (

We have designed and fabricated, for the first time to our knowledge, novel superluminescent diodes by using active multimode interferometers that emit at a wavelength of 1.55 ¿ m. An output power as high as 115 mW was obtained with a wide 3-dB bandwidth of 50 nm and low spectral ripple of 0.03 dB. In addition, they showed stable single-transverse-mode outputs up to the maximum output power.

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1timesN active multimode-interferometer (MMI) laser diodes (LDs), with integrated phase-match region, are demonstrated as phase-locked array LDs. In general, the phase of output ports of MMI divider is not the same for all N ports. This phase-mismatch leads to enormous excess loss inside the 1timesN active MMI-LD cavity, which results in very low quantum efficiency or even no lasing. Therefore, we integrate the phase-match region, which can lead to regular lasing, without any enormous excess loss. The implemented 1times3 active MMI-LDs showed lasing with no enormous degradation of quantum-efficiency. Additionally, significant output power increase of 200 mW was observed, compared to the regular single stripe LDs fabricated simultaneously, with the phase-locked condition.

mW) Superluminescent Diodes by Using Active Multimode Interferometer

1.55 µm InGaAsP/InGaAsP multiple quantum well (MQW) asymmetric active multimode laser diode (active MMI-LD) with split pumping scheme has been demonstrated. Asymmeric configuration ensures the singlewavelength output from the designed device. Moreover, the advantage of having large multimode active pumping section behind the splitted modulation section is the key contributor for having higher photon density in modulation section without increasing the device length. By utilizing the split pump configuration in the designed active MMI-LD, high intrinsic 3 dB modulation bandwidth of 24.6 GHz is achieved. To the best of our knowledge this is the highest reported intrinsic modulation bandwidth for active MMI-LD. Required photon density to achieve more than 40 GHz 3 dB bandwidth for direct modulation is also clarified.