Bragg Reflection Waveguide Lasers Research Articles

A Bragg reflection waveguide laser operating at an exceptional point

A vertical Bragg reflection waveguide (BRW) laser is proposed and simulated for reaching single-mode output, which operates at an exceptional point (EP). We study the properties of the EP-BRW laser using both the transfer matrix method and the traveling wave model. The mode selection mechanism for the EP-BRW laser and the key design parameters for optimum performance are analyzed. The effect of the EP on laser performance is investigated to achieve high confinement transversely of the optical field and low threshold gain. At the EP, such laser system exhibits exotic behaviors, such as high transverse gain, high single-mode stability, and high slope efficiency.

Near-diffraction-limited Bragg reflection waveguide lasers.

We report a near-diffraction-limited tapered Bragg reflection waveguide laser (BRL) with a 10μm ridge width, which is significantly larger than the conventional design. The large mode expansion in the vertical waveguide enables a scalable increase in the ridge width for single lateral mode operation. The role of the taper angle in the performance of tapered BRLs with the intrinsic characteristics of a thick vertical waveguide was investigated. The results indicate that the BRL with a taper angle of 3° shows the best far-field performance. An extremely low vertical divergence angle of 14.5° and a lateral divergence as low as 2.8° for 95% power inclusion were realized. A continuous-wave power exceeding 1W was demonstrated. Over the entire operating current range, the vertical beam is almost unchanged with an excellent beam quality (M2) of about 1.3. Lateral beam width increases slightly at higher currents due to the increasing contribution of side lobes, but it still remains nearly diffraction-limited with a lateral M2 of less than 2. Narrow beam divergence and high beam quality of the lasers allow simple and inexpensive collimation and coupling.

Semiconductor optical parametric generators in isotropic semiconductor diode lasers

We report on the characteristics of an intracavity semiconductor optical parametric generator in multiple-quantum well AlGaAs/InGaAs Bragg reflection waveguide lasers emitting between 986 and 995 nm. The cavity of the laser is phase-matched for down-conversion of pump photons to a signal between 1739 and 1767 nm and an idler between 2235 and 2328 nm. The normalized conversion efficiency is calculated to be 1.23×103 %W−1cm−2 above laser threshold and 1.25×104 %W−1cm−2 below threshold. The demonstrated device is potential for the realization of integrated parametric devices such as electrically pumped entangled photon-pair sources and optical parametric oscillation, where quantum optical effects can unfold.

布拉格反射波导激光器的光谱特性

The continuous-wave single-mode operation of edge-emitting diode laser based on dual-sided non-quarter-wave Bragg reflection waveguide (BRW) was demonstrated at room temperature. A low-index core was utilized in the laser. The ridge BRW lasers (BRLs) exhibited an ultra-narrow twin-beam output. Single longitudinal mode emission with a very small spectral linewidth of 0.052 nm was measured. The lasing spectra showed a periodic modulation in the envelope with a mode spacing of approximately 3.3 nm. When the injection current of the BRLs was beyond 300 mA, a large mode hopping of the emission wavelength was observed.

High power single-sided Bragg reflection waveguide lasers with dual-lobed far field

We report on 980-nm InGaAs/GaAs lasers with dual-lobed far field based on a single-sided Bragg reflection waveguide (BRW). The high slope efficiency ∼0.92 W/A and a continuous wave (CW) output power >1.5 W (3.2 W pulsed) have been obtained. The threshold current density is as low as 253 A/cm2 for a 1.5-mm-long device and the transparency current density is only 140 A/cm2. The further analysis shows the intrinsic reason for the single-lobed or the dual-lobed far-field distribution is determined by the mode shape in the cavity, not the single-sided or dual-sided BRW structure. The condition to achieve a narrow single-lobed far-field distribution is discussed.

Bragg reflection waveguide diode lasers

What we believe to be the first demonstration of an edge-emitting Bragg reflection waveguide laser is reported. The laser utilized InGaAs quantum wells emitting at 980 nm, with Al(x)Ga(1-x)As core and claddings. The lasing mode is centered in a low-index core with a width of 700 nm, hence providing a large mode volume with strong discrimination against any modes other than the fundamental photonic bandgap mode. Single-transverse mode operation is observed with thresholds as low as 157 A/cm(2). The propagation losses of the mode were measured for the first time and found to be 11.4 cm(-1).