NEC: News Release 97/08/07-02

Press Release

                                   Contact:-
                                   Aston Bridgman	
                                   NEC Corporation	
                                   TEL: 81-3-3798-6511
                                   FAX: 81-3-3457-7249
                                   E-mail: Aston_Bridgman@HO-PRD.ccgw.nec.co.jp


*****For immediate use August 7, 1997

NEC Releases 1.55u(micro)m-band DFB Laser Diode Module

~ Achieves a Non-Repeated Optical Transmission Distance of 600Km ~

NEC Corporation (NEC) has successfully developed a semiconductor modulator integrated 1.55 micro

m band distributed feedback laser diode (DFB-LD) module offering a bit rate of 2.5 gigabits/sec. (Gbps), intended for trunk line optical communications.

The DFB-LD module (product number NDL7910P) will be capable of supporting non-repeated transmission over a distance of up to 600km over existing optic fibers, five times the distance possible with current devices.

The main features of the NDL7910P include:

The first-ever successful application of NEC's unique select MOVPE1 growth technology, which permits the simultaneous formation of a DFB laser and a modulator on a single silicon wafer, with minimum light reflection between the DFB laser and the modulator;
A window structure introduced for the first time in communication laser technology that reduces the reflection ratio of the facet to 0.1%.

As a result of these features, it has been possible to achieve a non-repeated transmission distance of 600km in optical communications over existing 1.3 micro m zero-dispersion fibers at a bit rate of 2.5Gbps, or approximately five times the distance achieved with conventional laser diodes.

Sample shipments of the product commenced from July, and sales are being conducted worldwide. Volume production is expected to begin in the first quarter of 1998.

Background

In connection with the dramatic development of data communication systems such as intranets and cable television (CATV) in recent years, there has been a corresponding increase in the demand for trunk line optical communication systems linking these networks. At present, the mainstream trunk line optical communications market with transmission at a bit rate of 2.5Gbps is anticipated to grow at an annual rate of 20%. With 2.5Gbps optical communication, there are problems that have to be resolved to achieve large-volume data transmission over long distances using the existing fiber infrastructure.

The new product has been developed with this objective in mind. By utilizing an integrated semiconductor modulator, the DFB-LD module more effectively eliminates wavelength fluctuations. This is achieved because conventional direct modulation systems cause wavelength fluctuations as the laser itself modulates on and off. By allowing the laser to continuously emit and instead control modulation through the integrated semiconductor modulator, the NDL7910P not only achieves clearer signals but offers this in a cost-effective single package, whereas previously a more costly solution requiring separate modulator device had been necessary.

To simplify its application, the NDL7910P is mounted in the same butterfly-type package as existing products, with a built-in 50 ohm impedance-matching circuit to facilitate board mounting.

For Main specifications for the NDL7910P, please see the attached sheets.

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