Fabrication and characterization of narrow stripe InGaAsP/InP buried heterostructure lasers

To meet the stringent requirements of a submarine cable system, our 1.3-μϊα laser prequalification program has two objectives-first, to define the testing methodology that will accurately evaluate the potential reliability of the laser; and second, to obtain a preliminary indication of laser reliability on which the system configuration can be designed. Our testing methodology involves a combination of step-temperature, step-power, and isothermal test ing over the temperature interval between 10 and 80°C and power levels of 1 to 5 mW per facet. Our results show that the long-term degradation process is thermally accelerated, with a median activation energy of 1 eV and a standard deviation of 0.13 eV. By using these activation energies, in conjunc tion with our measurements of degradation rates, we can project laser perform ance to 10°C, i.e., system operating temperature. It is estimated that the median time to failure for "light bulb" operation at 10°C is over 2 X 10 7 hours; and with 98-percent probability it is greater than 5 X 10 6 hours. Hence, when viewed strictly in terms of light bulb sources of stimulated power, these 1.3-μιη lasers have adequate life. In addition, other potential operational malfunc tions are being investigated, and they do not seem to change our basic conclusion about the usefulness of these 1.3-μνα lasers for submarine cable application.

Section: Introductionmentioning

confidence: 99%

1.3-μm Laser Reliability Determination for Submarine Cable Systems

Hakki

Fraley

Eltringham

1985

“…We first discuss the strongly index-guided lasers. Over the last few years, we have fabricated the Channeled Substrate Buried Heterostructure (CSBH), 37 the Etched Mesa Buried Heterostructure (EMBH) 38 · 39 and the Double-Channel Planar Buried Heterostructure (DCPBH) 40 lasers (see Fig. 9).…”

Section: Resultsmentioning

confidence: 99%

Performance Comparison of InGaAsP Lasers Emitting at 1.3 and 1.55 μm for Lightwave System Applications

Dutta

Wilson²,

Wilt

et al. 1985

Experimental results relative to the performances of real index-guided InGaAsP lasers emitting near 1.3 and 1.55 μΐη are described and compared. The laser structures discussed are the etched mesa buried heterostructure, channeled substrate buried heterostructure, and the double channel planar buried heterostructure. The effect of Auger recombination and intervalence band absorption on the threshold current and external differential quantum efficiency is discussed. The effect of the larger Auger coefficient at 1.55 μπι is compensated by a lower carrier density at threshold at 1.55 μπι so that the total nonradiative current loss for lasers emitting at 1.55 μπι is not significantly larger than that for lasers emitting at 1.3 μΐη. A small linear shunt leakage current (~10 mA) can increase the T 0 to ~100K. We report threshold currents as low as 11 and 15 mA (at 30°C) and continuous-wave operating temperatures as high as 130 and 110°C for lasers emitting at 1.3 and 1.55 μηι, respectively.

“…There are three ways in which such Au fragments could be inimical to laser reliability: (1) Light blockage-in the course of system instal lation, long-term mechanical relaxation, or mechanical vibration tests, fragments within the mesa might move to partially obstruct the optical output. (2) Electrical shorting-the recovery of lasing operation after sudden termination, effected by mechanical removal of Au fragments from the mirror of a laser that exhibited no preceding or subsequent signs of degradation, suggested that the torn metal could externally short the p-n junction.…”

Section: Optical Inspectionmentioning

confidence: 99%

Implementation of the Proposed Reliability Assurance Strategy for an InGaAsP/InP, Planar Mesa, Buried Heterostructure Laser Operating at 1.3 μm for Use in a Submarine Cable

Nash

Sundburg

Hartman

et al. 1985

We discuss the implementation of a strategy designed to provide laser-lightemitting reliability assurance for 1.3-μνα InGaAsP/lnP lasers of the planar mesa, buried heterostructure type for use in a submarine cable application. The testing regimes include initial characterization (cosmetic and light-current curve inspection), passive aging (elevated temperatures [85 to 175°C] without bias, with and without humidity [<85-percent relative humidity]), overstress active aging (high temperatures [150°C], high currents [250 mAdc]), and longterm rate-monitoring active aging (elevated temperature [60°C] burn-in [3 mW/facet]). Overstress testing is designed to compel a timely (~10 2 -hour) identification of premature failures, due to modes of degradation other than the long-term ultimately controlling wear-out mode, and to stabilize transient modes. To identify premature failures of the wear-out type, survivors of overstressing are subjected to rate monitoring in which wear-out degradation rates, established in a reasonable time (~10 3 hours), may be sorted. The principal results of the important overstress aging were the detection of an initially occurring saturable degradation mode, present to some extent in most lasers, and a regimen to force its rapid stabilization, so that it would not obscure determination of the activation energy of the wear-out mode. With a credibly determined value for the latter, it was deterministically inferred from * Authors are employees of AT&T Bell Laboratories.