Abstract

There have been substantial efforts to develop the efficient optical add/drop multiplexer (OADM) using arrayed-waveguide gratings (AWG’s) for wavelength-division-multiplexed (WDM) networks.^1–4 For example, it has been proposed to implement the OADM by using a pair of 1 × N AWG’s.¹ However, this technique requires two AWG’s operating at the same wavelengths. To avoid this problem and minimize cost, it has been proposed to implement the OADM by using an AWG in loop-back configuration.² This OADM utilizes only one N × N AWG and could support up to N – 1 channels. However, this technique is inherently sensitive to the first-order intraband crosstalk. The OADM could also be implemented by using a 2 × N multiplexer in fold-back configuration.³ However, this technique could utilize only N/2 channels, although it is immune from the first-order crosstalk. Recently, this technique has been improved to support all the N channels at the cost of additional N optical bandpass filters.⁴ In this paper, we propose and demonstrate a simple OADM using one 2 × N AWG and couplers. Unlike the previous techniques in,⁴ the proposed technique could support all the N channels without using the optical bandpass filters. In addition, we found that the suppression of the first-order crosstalk would not necessarily improve the performance of OADM because of the crosstalk caused by reflection from inside of the AWG.

© 2002 Optical Society of America