In this paper, we present the fabrication of 40 Gb/s traveling‐wave electroabsorption modulator‐integrated laser (TW‐EML) modules. A selective area growth method is first employed in 40 Gb/s EML fabrication to simultaneously provide active layers for lasers and modulators. The 3 dB bandwidth of a TW‐EML module is measured to be 34 GHz, which is wider than that of a lumped EML module. The 40 Gb/s non‐return‐to‐zero eye diagram shows clear openings with an average output power of +0.5 dBm.

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A distributed Bragg reflector (DBR) laser and a high speed electroabsorption modulator (EAM) are integrated on the basis of the selective area growth technique. The typical threshold current is 4 to 6 mA, and the side mode suppression ratio is over 40 dB with single mode operation at 1550 nm. The DBR laser exhibits 2.5 to 3.3 mW fiber output power at a laser gain current of 100 mA, and a modulator bias voltage of 0 V. The 3 dB bandwidth is 13 GHz. A 10 Gbps non‐return to zero operation with 12 dB extinction ratio is obtained. A four‐channel laser array with 100 GHz wavelength spacing was fabricated and its operation at the designed wavelength was confirmed.

We propose and demonstrate a tunable external cavity laser (ECL) composed of a polymer Bragg reflector (PBR) and integrated gain chip with gain, a ring resonator, an electro-absorption modulator (EAM), and a semiconductor optical amplifier (SOA). The cavity of the laser is composed of the PBR, gain, and ring resonator. The ring resonator reflects the predetermined wavelengths into the gain region and transmits the output signal into integrated devices such as the EAM and SOA. The output wavelength of the tunable laser is discretely tuned in steps of about 0.8 nm through the thermal-optic effect of the PBR and predetermined mode spacing of the ring resonator.

We fabricated electroabsorption modulated distributed feedback (DFB) laser diodes for 40 Gbps application through the selective-area growth method. The facet reflection was not sufficiently removed by just depositing the anti-reflection coating so that low frequency resonance occurred by optical feedback from the facet to the DFB laser. A tilted facet formed by dry etching processes successfully reduced the optical feedback and the resonance in E/O response decreased significantly.