3 March 2011

Mitsubishi develops first monolithically integrated 43G RZ-DQPSK transmitter

At next week’s Optical Fiber Communication Conference (OFC 2011) in Los Angeles, CA (6–10 March), Tokyo-based Mitsubishi Electric Corp will present what it claims to be the first fully monolithically integrated laser diode for use in transmission devices that transmits large date volumes between metropolitan areas at 43Gbps using return-to-zero differential quadrature phase-shift keying (RZ-DQPSK).

With transmission volume over optical communication networks increasing rapidly, densely spaced wavelength division multiplexed channels, higher-bit-rate transmission and multi-level formats such as DQPSK are in demand for long-distance transmission, says Mitsubishi Electric. Previously, it was common for transmission device makers to use several different chips (such as LiNbO3 Mach–Zehnder modulators and tunable lasers). However, devices measure several centimeters or more in length and require relatively large driving power.

Mitsubishi Electric now claims to have achieved the first monolithic integration of three functional chips — a tunable laser array (whose wavelength can be controlled between 1572nm and 1612nm), an RZ Mach–Zehnder modulator (which modulates the output power intensity) and a DQPSK Mach–Zehnder modulator (which modulates the signal phase) — into a single chip. Mitsubishi Electric has hence developed what it claims is the first 40G RZ-DQPSK transmitter monolithically integrated with a tunable distributed feedback (DFB) laser array and Mach–Zehnder modulators.

The fully monolithic integration and InP-based modulator effectively minimize device size and power consumption. The chip's dimensions are 9.6mm x 0.75mm (less than one hundredth of the size of conventional chips). The module's volume, including the chip, can hence be minimized to less than one third of the size of conventional modules, says the firm.

The new laser diode achieves tuning control over 95 channels on the 50GHz grid of the International Telecommunication Union Telecommunication Standardization Sector (ITU-T) covering a 40nm wavelength range over the L-band from 1572nm to 1612nm.

Mitsubishi Electric says that in future it plans to enhance the performance of high-power, low-consumption and clear optical waveforms, and to aso develop a light source for C-band wavelengths (from 1530nm to 1570nm).

Tags: Mitsubishi RZ-DQPSK transmitter

Visit: www.MitsubishiElectric.com

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