Two-wavelength semiconductor laser device

Abstract

The invention provides a two-wavelength semiconductor laser device with optimized knee level, working voltage, temperature characteristic and horizontal spread angle. The semiconductor laser device has a first light emitting portion and a second light emitting portion having a longer emission wavelength than that of the first light emitting portion. Each of the first light emitting portion and the second light emitting portion has a stripe-shaped ridge structure used for carrier injection. The ridge structure in the first light emitting portion includes a first front end region having a width Wf1 and having a length L3 from a front facet, a first rear end region having a width Wr1 and having a length L1 from a rear facet, and a first tapered region located between the first front end region and the first rear end region and having a length L2, and the relation of Wf1>Wr1 is satisfied. The ridge structure in the second light emitting portion includes a second front end region having a width Wf2 and having a length L6 from a front facet, a second rear end region having a width Wr2 and having a length L4 from a rear facet, and a second tapered region located between the second front end region and the second rear end region and having a length L5, and the relation of Wf2>Wr2 is satisfied. The relations of L1+L2+L3=L4+L5+L6, Wf1<Wf2, and L1>L4 are also satisfied.

Description

technical field [0001] The present invention relates to a semiconductor laser device used as a light source for an optical pickup of an optical disc device, or a light source for other electronic devices, information processing devices, etc., and particularly relates to a dual-wavelength semiconductor laser device in the red region and infrared region. Background technique [0002] In the past, large-capacity digital versatile discs (DVDs) and DVD playback devices capable of high-density recording have been sold in the market, and they are attracting attention as products that will increase in demand in the future. Since DVD is recorded at a high density, the laser light source for recording and reproduction uses an AlGaInP semiconductor laser with an emission wavelength of 650nm. In this way, the optical pickup of the conventional DVD device cannot record and reproduce the CD-R that uses the AlGaAs-based semiconductor laser with an emission wavelength of 780 nm to record an...

AI Technical Summary

Problems solved by technology

[0034] but just Figure 11 In the shown two-wavelength semiconductor laser device in which the red laser and the infrared laser are integrated on the same substrate, since the resonator lengths of the red laser and the infrared laser are the same, there is a problem that does not occur in the case of a single-wavelength laser.

[0035] Generally speaking, compared with infrared lasers, red lasers have the following characteristics problems: low inflection point level, poor temperature characteristics (temperature rise leads to obvious increase in threshold value, operating current, etc.), high operating voltage, etc.

[0036] However, in a dual-wavelength semiconductor laser device, if the resonator length is increased in order to improve the characteristics of the red laser, the resonator length will be longer than the optimal resonator length satisfying the characteristics for the infrared laser, so, In infrared lasers, the tilt characteristic will be reduced and the operating current will be increased

Images