M. G. Young

Widely Tunable InGaAsP/InP Laser Based on a Vertical Coupler Intracavity Filter

Widely tunable semiconductor lasers are critical components for future wavelength division multiplexed networks and switching systems. Indeed, the total capacity of such systems is presently limited by the laser tuning range. The electrical tuning range of DFB and DBR lasers is limited to less than ~15nm. This limitation results from the fact that the fractional tuning range, Δλ/λ, of the fine-pitch Bragg grating wavelength-selective reflector is simply proportional to the normalized effective index change, ΔN/N. However, we have recently demonstrated that the grating-assisted vertical coupler provides an attractive bandpass filter that can be electrically tuned over a range substantially greater than a grating reflector for the same induced refractive index change [1,2]. Indeed, very recently a tunable twin guide laser that includes a vertical coupler structure between two nearly-synchronous guides exhibited evidence of extended, but irregular tuning [3]. Here we report a novel monolithic extended cavity laser with an integrated grating-assisted vertical coupler as a tunable intracavity filter. This laser has measured tuning range of 57nm and a tuning response that depends monotonically on the filter tuning current.

High power laser-amplifier photonic integrated circuit for 1.48 micron wavelength operation

Laser-amplifier photonic integrated circuits (PIC’s) with high coupling efficiency between the laser and amplifier elements, using the InP material system, have been described previously [l-3]. Surface emitting laser amplifier devices have also been reported in the GaAs system using second order Bragg reflector gratings [4]. In the present work we describe a strained layer MQW laser-amplifier PIC intended for use as a high power source for pumping erbium doped fiber amplifiers (EDFA’s) at 1.48 micron wavelength. Multiple quantum well (MQW) optical amplifiers have extremely high saturation output powers [5,6], making them very suitable for high power applications.