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A wavelength tunable V-cavity laser (VCL) employing integrated thin-film heaters is reported. The laser is fabricated by a simple process with no grating or band-gap engineering. A single-electrode-controlled wavelength tuning of 32 channels is achieved by experiment, with a tuning efficiency of 0.13 nm/mW, which is about 1.5 times higher than that of the current injection based thermal tuning. By combining four single-electrode controlled tunings with different bias currents, we obtain 51 wavelength channels covering 43 nm. Well-open eye diagrams with extinction ratios above 6.6 dB are obtained in all channels under direct modulation at 2.5 Gbps. The power penalty over a 25-km fiber transmission is less than 0.3 dB. Clearly open eye diagrams with bit error rates (BERs) below 10-12 are also obtained at 5 and 8.5 Gbps after a 10-km single-mode fiber transmission.

An 870-nm-band wavelength tunable edge-emitting semiconductor laser based on V-coupled cavities in a GaAs/AlGaAs material system is presented. It does not involve any grating or epitaxial regrowth. Using a single electrode control, 31-channel wavelength tuning with a channel spacing of about 0.38 nm is achieved, with a tuning range of 11.4 nm. By additionally varying the temperature from 8°C to 50°C, wavelength tuning of 60 channels over 22.4 nm is demonstrated. At lower tuning current and with a temperature variation of 18°C, wavelength switching by carrier plasma effect is achieved with a tuning range of 8.2 nm. The simple and compact 870-nm-band edge-emitting tunable laser is suitable for multifunctional photonic integration for optical interconnect and biomedical applications.