Feasibility Study on High Data Transfer Rate of 300 Mbit/s with 8-Beam Laser Diode Array

Abstract

This study aims at achieving a high speed optical disk drive for multimedia storage used in network systems. The feasibility of our target has been confirmed by the following results and techniques. High speed parallel data transfer at 336 Mbit/s in 2/7 run length limited (RLL) code or 300 Mbit/s in 1/7 RLL code has been achieved experimentally with eight beams. Focus offset has been reduced by a multibeam laser diode fabricated in junction down structure and a wide-angle lens system. Tracking error is reduced by nearly 6 dB compared with that of a conventional method. This was achieved by suppressing the mechanical interaction between the lens actuator and the beam rotation prism. The crosstalk canceler reduces both intercircuit crosstalk and optical crosstalk with pseudo crosstalk generated by a circuit. It reduces the worst-case intercircuit crosstalk by more than 14 dB.

Blue-Violet Four-Beam Light Source Using Waveguides

“…Figure 2(a) shows the basic configuration of a conventional optical recording head employing a laser diode array (conventional head). [6][7][8] Multiple beams, which are emitted simultaneously, are optically combined using a collimator lens. Then, multiple optical spots simultaneously form on the optical disk through one objective lens.…”

Parallel recording with optical waveguide array

“…In order to increase the data transfer rate, different approaches have been proposed such as: focusing the beam from a linear array of laser diodes onto different tracks operated in the far-field [1][2][3][4][5] , and using a linear array of sub-wavelength apertures operated in the near field [6][7][8][9] . Recently, it was proposed the use optical waveguide to achieve reading in the intermediate field [10][11][12][13][14] , and the use of multimode rectangular multi-mode waveguide as an imaging system 13,14 .…”