David Mehuys

Operating characteristics of a high-power monolithically integrated flared amplifier master oscillator power amplifier

High-power monolithically integrated flared amplifier master oscillator power amplifiers (MFA-MOPAs) that operate up to 2 W continuous wave (CW) in a single diffraction-limited lobe have been fabricated. The spectral output of the MFA-MOPA is single longitudinal mode with a side-mode suppression ratio greater than 25 dB. Several operating characteristics of the MFA-MOPA, including the beam astigmatism, amplifier gain saturation, linewidth, far-field extinction ratio, and beam quality metrics are investigated and discussed. >

2.0 W CW, diffraction-limited operation of a monolithically integrated master oscillator power amplifier

The authors fabricated a monolithically integrated master oscillator power amplifier, M-MOPA, with a flared power amplifier region which radiates in a single diffraction limited lobe to an output power in excess of 2 W CW. The radiation pattern is stable with increasing drive current. The spectral output of the M-MOPA is a single longitudinal mode with a side-mode suppression ratio greater than 25 dB.<<ETX>>

Laser diode pumped 106 mW blue upconversion fiber laser

A laser diode pumped Tm3+‐doped ZBLAN fiber upconversion laser is demonstrated with blue output power levels up to 106 mW. Differential optical‐to‐optical conversion efficiencies up to 30% are measured with respect to pump power coupled into the upconversion fiber. A single spatial mode blue output beam is demonstrated, with an M2 value of 1.4.

Numerical analysis of flared semiconductor laser amplifiers

A numerical model for flared semiconductor optical amplifiers that incorporates the effects of gain and index saturation and thermal effects is presented. Theoretical near fields, far fields, and quadratically phase-corrected far fields are presented. The results indicate that flared semiconductor laser amplifiers are capable of coherent diffraction-limited output powers in excess of 1 W CW. >

Modal analysis of linear Talbot-cavity semiconductor lasers

A modal analysis at threshold is presented for linear Talbot-cavity semiconductor lasers with a finite number of array elements. The analysis self-consistently calculates the array supermode profiles and the loss each incurs owing to imperfect Talbot imaging, including edge diffraction losses. It is found that the decrease in mode discrimination between supermodes incurred by fabricating larger arrays can be offset by reducing the near-field fill factor.

Technique for lateral temperature profiling in optoelectronic devices using a photoluminescence microprobe

A photoluminescence microprobe technique with ≤0.2 °C and <5 μm resolution is demonstrated for measuring lateral temperature profiles in GaAs‐based optoelectronic devices. The technique is used to measure the junction‐heating induced temperature gradient in both single‐stripe and broad‐area diode lasers. The effective focal length of the thermally induced refractive index gradient lens is determined from the temperature gradient in a broad‐area device.

5.25-W CW near-diffraction-limited tapered-stripe semiconductor optical amplifier

A broad-area tapered-contact single-pass amplifier emitting at 860-nm wavelength is demonstrated to emit up to 5.25 W continuous wave (CW) in a near-diffraction-limited radiation pattern. The diffraction-limited component of the radiation pattern, comprising greater than 87% of the total power at 5.25-W CW output, is observed to decrease slightly with increasing drive current due to filament formation. The output beam astigmatism is found to saturate at high power output in accordance with gain saturation, which indicates that the high-quality output beam remains stable with respect to small changes in current or injected power.<<ETX>>

High-power, near-diffraction-limited large-area traveling-wave semiconductor amplifiers

Operating characteristics of high-power large-active-area GaAlAs amplifiers configured in double-pass and single-pass traveling-wave arrangements are described. Single-pass broad-area amplifiers with a 600- mu m stripe width generated up to 21 W of near-diffraction-limited emission under pulsed operation when injected with 500 mW from a Ti:Al/sub 2/O/sub 3/ laser, and 11.6 W when injected with 100 mW from a laser diode master laser. In CW operation, a broad-area amplifier output of 3.3 W was demonstrated. Tapered-stripe large-area amplifiers emitted up to 4.5 W in a near-diffraction-limited beam when injected with 150 mW from a Ti:Al/sub 2/O/sub 3/ laser. The physical mechanisms causing degradation of the output beam phase front and intensity uniformity at high output power levels, including thermal lensing and filamentation, are presented. >

2.2-W continuous-wave diffraction-limited monolithically integrated master oscillator power amplifier at 854 nm

A monolithically integrated master oscillator power amplifier (M-MOPA) with a flared power amplifier region operating at 854 nm has been fabricated that radiates in a single diffraction-limited lobe to an output power of 2.2-W continuous wave (CW). Additionally, the far field is extinguished by 26 dB with the master oscillator turned off enabling applications requiring digital modulation.

Self-stabilized nonlinear lateral modes of broad area lasers

The lateral modes of broad area lasers are investigated theoretically. The nonlinear interaction between optical field and effective refractive index leads to a saturable nonlinearity in the governing field equation, so that self-modulated solutions are found to be stable with increased current injection above saturation intensity. We derive approximate analytical solutions for traveling wave fields within the broad area laser. The field amplitude consists of a small ripple superimposed on a large dc value. Matching fields at the boundary determines the modulation depth and imparts an overall phase curvature to the traveling wave mode. There are multiple lateral modes for a given set of operating conditions, and modes with successively more lobes in the ripple have greater overall phase curvature. In contrast to the linear problem, several lateral modes can achieve the same modal gain, for a given injected current density, by saturating the gain to different extent. Thus, these modes would exhibit slightly different optical powers.