J. Connolly

High power 1550 nm distributed feedback lasers with 440 mW CW output power for telecommunication applications

Summary form only given. High power 1550 nm InGaAsP/InP single-frequency distributed-feedback lasers with record output powers are reported. Ex-facet power levels of 440 mW and single-mode fiber power of 340 mW have been achieved for CW operation at 20/spl deg/C.

High power InGaAsP/InP broad-waveguide single-mode ridge-waveguide lasers

Single-mode broad-waveguide separate confinement ridge-waveguide InGaAsP/InP diode lasers emitting in 1500 nm wavelength range have realized cw output power levels in excess of 400 mW. The high-power broad-waveguide structure design and ridge-waveguide fabrication technology along with device operational performance parameters will be discussed.

High power Raman pumps based on ridge waveguide InGaAsP/InP diode lasers

This paper presents data on 14xx nm ridge waveguide InGaAsP/InP pump lasers with record powers and efficiency as well as results obtained using these lasers in both fiber-optic modules and Raman pump blocks.

Waveguide collapse In InGaAsP ridge-waveguide lasers with weak lateral optical confinement

Summary form only given. The maximum CW powers for single-mode diode lasers are limited by tolerable current and photon densities in their active regions. The maximum width of a single-mode laser active region is inversely proportional to /spl radic//spl Delta/n/sub B/, where /spl Delta/n/sub B/ is the built-in refractive index step at the active region boundary. In this paper, /spl lambda/=1.5 /spl mu/m InGaAsP/InP SCH 3QW broad-waveguide (600 nm) ridge waveguide lasers with low values of /spl Delta/n/sub B/ (5 - 7/spl times/10/sup -3/) have been investigated.

14xx nm DFB InGaAsP/InP pump lasers with 500 mW CW output power for WDM combining

In conclusion, we have demonstrated 14xx nm DFB pump InGaAsP/InP ridge waveguide lasers with a record CW chip power level of 500 mW and ex-fiber or module power of 300 mW. Narrow emission line with very weak current/temperature peak position dependence allows us to use conventional wavelength multiplexing techniques to combine output of DFB pumps with different wavelengths into one SM fiber. Outputs from two 14xx nm DFB lasers with wavelengths differing by 16 nm have been combined in one SM fiber with efficiencies close to 90%, thereby producing a total 14xx nm power level of 500 mW.

High Power 1300 nm Fabry-Perot and DFB Ridge Waveguide Lasers

In this paper we summarize the results on the development of high power 1300 nm ridge waveguide Fabry-Perot and distributed-feedback (DFB) lasers. Improved performance of MOCVD grown InGaAsP/InP laser structures and optimization of the ridge waveguide design allowed us to achieve more than 800 mW output power from 1300 nm single mode Fabry-Perot lasers. Despite the fact that the beam aspect ratio for ridge lasers (30 degree(s) x 12 degree(s)) is higher than that for buried devices, our modeling and experiments demonstrated that the fiber coupling efficiency of about 75-80% could be routinely achieved using a lensed fiber or a simple lens pair. Fiber power of higher than 600 mW was displayed. Utilizing similar epitaxial structures and device geometry, the 1300 nm DFB lasers with output power of 500 mW have been fabricated. Analysis of the laser spectral characteristics shows that the high power DFB lasers can be separated into several groups. The single frequency spectral behavior was exhibited by about 20% of all studied DFB lasers. For these lasers, side-mode suppression increases from 45 dB at low current up to 60 dB at maximum current. About 30% of DFB lasers, at all driving currents, demonstrate multi-frequency spectra consisting of 4-8 longitudinal modes with mode spacing larger than that for Fabry-Perot lasers of the same cavity length. Both single frequency and multi frequency DFB lasers exhibit weak wavelength-temperature dependence and very low relative intensity noise (RIN) values. Fabry-Perot and both types of DFB lasers can be used as pump sources for Raman amplifiers operating in the 1300 nm wavelength range where the use of EDFA is not feasible. In addition, the single-mode 1300 nm DFB lasers operating in the 500 mW power range are very attractive for new generation of the cable television transmission and local communication systems.

Non-thermal saturation of P-I characteristics for InP- and GaSb-based broad-contact SCH-QW lasers

Summary form only given. High-power pulsed eye-safe IR laser diodes are currently of increasing interest for applications including range finders and IRCM systems. The output power for InP-based lasers is limited by power-current (P-I) characteristics saturation (rollover effect) rather than by the catastrophic optical damage of the mirror facets as observed for shorter wavelength devices. The current leakage from the quantum well active region has been considered as one of the main reasons of the rollover effect. We present data on the studies of P-I characteristics in the short pulsed regime for broad-contact InP-and GaSb-based separate-confinement heterostructure double-quantum-well (SCH-DQW) lasers emitting in the wavelength range 1.45-1.95 /spl mu/m.

Packing techniques to increase wavelength tuning of distributed feedback lasers

Summary form only given. Distributed feedback (DFB) diode lasers are used as sources in laser absorption spectrometers for trace gas analysis. Many molecules, including common environmental pollutants and toxic chemicals, have absorption bands between 760 nm and 2004 nm. These bands are strong enough to allow detection at or below the parts-per-million (ppm) level. In order to sweep through an absorption peak a wavelength tuning range of over one wave number is typically required. In FM spectroscopy the wavelength of the laser is tuned with temperature close to the absorption peak. A low-frequency (ranging from a few Hz to 1 kHz) saw tooth current ramp is then applied to the diode laser that repetitively sweeps its emission frequency across the absorption peak. One needs as high as possible a current tuning rate for as small as possible a current change to minimize power changes and non-linearity.

Advanced high-power superluminescent light sources for environmental, chemical, and biological sensing applications

In this paper we demonstrate high-power GaAs-based and InP-based superluminescent diodes (SLD) with tilted waveguides emitting in 8xx nm and 15xx nm spectral ranges respectively. The analysis of devices with different cavity lengths emphasizes the tradeoff between output power and spectral width. Power levels of about 200 mW for 820 nm SLDs and about 100 mW for 1590 nm SLDs have been demonstrated for longer cavity devices. Spectral modulation was less than 6-7% at 70-80 mW output power for both 8xx and 15xx SLDs. Simple model proposed for evaluation of spectrum modulation for both GaAs and InP devices based on semi-empirical approach is in agreement with experimental observations.

Spectral and noise characteristics of Fabry-perot and DFB 14xx nm InGaAs/InP pump lasers for Raman and Er-doped fiber amplifiers

14xx nm InGaAsP/InP DFB and Fabry-Perot ridge waveguide lasers with comparable performance were fabricated. Spectral and noise characteristics of these devices are compared and contrasted. Single frequency and multifrequency DFB devices display low RIN values of -165 dB/Hz.