Coupled cavity InGaAsP/InP laser for synthetic optical coherence tomography and other applications

The authors describe widely tunable coupled cavity semiconductor lasers with sub-microsecond switching times between modes over the operating range of ~100 nm. With appropriate modulation of injection currents and time averaging of the output, these devices provide short coherence lengths and can be an excellent source for synthesised optical coherence tomography (OCT). The depth resolution was found to be ~15 ??m for a 100 nm wavelength tuning range centred at 1580 nm. High-output power and brightness together with a short coherence length confers on these asymmetric multiple quantum well (AMQW) C³ laser some advantages over conventional sources for OCT. Also, a rapid wavelength switching capability allows the AMQW C³ lasers to be used in real-time OCT and other applications needing wavelength agile sources.