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July 6, 1998

Hitachi Releases Plastic Mini-DIL type Laser Diode

- Hitachi and Nortel joint development provides user-friendly features at low cost -

Recently, the volume of information and data handled by information communication systems has dramatically increased, and there is a move from conventional communication systems that use high-frequency cables and radio waves to optical communication systems that are more suitable for transmission of large volumes of information. There are trunk line optical communication systems with a transmission capacity of upward of several tens of gigabits a second.

Optical technology used in communication systems is in the process of being made available to subscribers and has already been applied up to the line terminal or curb, which is one step before the subscribers. The laser diodes that are used as the light source in subscriber optical communication systems need to be able to operate over a wide range of temperatures, and be low cost, compact, and user friendly. In the conventional technology, coaxial type^*4 laser diodes are used. However, coaxial laser diodes require reshaping of the leads when they are being installed in printed circuit boards. There is therefore a growing need for such laser diodes that are easier to handle and can be produced at a low cost.

Hitachi already produces 1,310nm coaxial type laser diodes for subscriber optical communication system applications. The new HL1328DJS can handle transmission rate of up to 622Mb/s. The cost of this product is kept down by assembling an InGaAsP laser diode in a plastic Mini-DIL package with a single mode fiber.

In the conventional method of coupling a laser diode and a single mode fiber, a laser diode is set to ON while adjusting the position of the laser diode and the fiber.

This is time consuming and does not lend itself to mass production. This HL1328DJS is produced by arranging a laser diode and a single mode fiber very precisely on the Si substrate having a V groove (Si-V groove technology) so that the laser diode and fiber can be coupled without setting the laser diode to ON for adjustments (Passive Alignment method). This technology facilitates mass production and lowers the cost.

The volume of the compact package (3mm in thickness, 13mm in length, and a pin width of 7.6mm) is 40% of that of existing coaxial type packages. The pin arrangement was jointly proposed by Hitachi, Lucent Technologies, and Nortel, and the 8-pin Mini-DIL pin assignment ment, which is becoming the industry standard, is used. This pin assignment is the same as for the conventional 14-pin metal DIL laser diode so product replacement without changing the circuit layout of the printed circuit board is possible. The operating temperature range is from -40 to +85 degrees Celcius, which is the same as that of a conventional coaxial type laser diode. Reliability is in compliance with the Bellcore983^*5 specification.

In the future, Hitachi will continue to develop communication laser diodes to cater to market requirements (low threshold current, high output, increased speed (2.5G)) based on the HL1328DJS. Nortel also is expected to develop products that use this technology, based on the joint development agreement.

Notes:	1.	Mini-DIL:
		Small dual In-Line. Mini-DIL has the same pin spacing and width as a normal IC DIL type. The Mini-DIL has the wide operating temperature range laser diode, monitor photo diode and fiber while the 14-pin metal DIL needs an additional cooler and thermistor because of use of a normal operating temperature range laser diode. Since these componets are assembled in a 8-pin compact package, the product is called the Mini-DIL.
	2.	Passive Alignment method:
		A technique for coupling a fiber and laser diode. In the conventional method, called the Active Alignment method, the laser and fiber are coupled while laser diode is on. This method couples the fiber and laser diode without switching the laser diode on. This enables rationalization of the assembly process.
	3.	Si-V groove technology:
		A laser diode module assembly technology for coupling a fiber and a laser diode to assemble the module at high precision in the Passive Alignment method. Since the technology fixes the diode by guiding optical fibers to a V shaped groove on the Si (silicon) substrate, the technology is called the Si-V groove technology.
	4.	Coaxial type:
		Generic term used to describe cylindrical (coaxial) packages. In general, coaxial type laser diodes refer to laser diodes, monitor photo diodes, and fibers. Using a laser diode having a wide operating temperature range, eliminates the need to use a cooler and a thermistor.
	5.	Bellcore983 specification:
		Technical document TA-NWT-000983 published by Bellcore, USA. This specifies the required reliability for laser diodes used for subscriber optical communication and is used as the de facto industry standard specification.

Application example

-Light source for a short to medium range 155 or 622Mb/s optical communication system
-Light source for measuring instruments

Price in Japan

Catalog No.	Sample price (yen) in lots of 1000 pieces
HLI 328DJS	8,000

About Hitachi

Hitachi, Ltd., headquartered in Tokyo, Japan, is one of the world's leading global electronics companies, with fiscal 1997 (ending March 31, 1998) consolidated sales of 8,417 billion yen(63.8 billion dollars^*). The company manufactures and markets a wide range of products, including computers, semiconductors, consumer products and power and industrial equipment. For more information on Hitachi, Ltd., please visit Hitachi's Web site at http://www.hitachi.co.jp.

^* At an exchange rate of 132 yen to the dollar.

About Nortel

By cooperating with users worldwide, Nortel (Northern Telecom Limited) is engaged in designing, construction, and integration of networks and provides a wide range of digital network products based on the vision of "A world of Networks". The concerned fields include information, entertainment, education, and business. Nortel provides many digital lines worldwide. (Turnover of 1997: About 15.5 billion dollars, Number of employees: About 73,000)

About Northern TELECOM Japan

Northern TELECOM Japan was established in 1983 as a Japanese corporation and is engaged in operation, sales, and support activities for the products of Nortel. As a foreign enterprise, this company supplies many office converters to Nippon Telegraph and Telephone Public Corporation (NTT) and also to International Digital Communication (IDC) Corporation. Northern TELECOM Japan also provides many enterprise network solutions to large finance companies and manufacturers in Japan.

Features

1. Plastic Mini-DIL package Plastic is used for the user friendly Mini-DIL package to provide further cost reduction.
2. Wide operating temperature range of -40 to +85 degrees Celcius Has the same operating temperature range as a conventional, wide-operating-temperature-range laser diode.
3. Compliance with Bellcore983 The product is highly reliable and can be used as a light source for optical communication systems.

Specification

1. Maximum absolute ratings (Tc=25 degrees Celcius)

Item	Symbol	Rating	Unit
LD forward current	IF(LD)	Ith+60	mA
LD reverse voltage	VR(LD)	2	V
PD forward current	IF(PD)	10	mA
PD reverse voltage	VR(PD)	15	V
Operating temperature range	Topr	-40 to +85	degree Celcius
Storage temperature range	Tstg	-40 to +85	degree Celcius

2. Electrical and optical characteristics (Tc=-40 to +85 degrees Celcius)

Measurement			Standard value
Item	Symbol	condition	Minimum	Standard	Maximum	Unit
Light output	Po	Kink-free	0.4	-	-	mW
Slope efficiency			0.01	-	0.03	mW/mA
Operating voltage	Vop	Pf=0.4mW	-	-	1.4	V
Oscillation wave length		Pf=0.4mW,RMS	1270	1310	1350	nm
Spectral width		Pf=0.4mW,RMS	-	-	2.5	nm
Monitor current	Is	Pf=0.4mW	200	-	-	mA
Tracking error		Pf=0.4mW, 25 degrees	-1	-	1	dB

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