Mode sensitive optical filter and optical transmitting set/receiver

Abstract

An optical transmitter / receiver provided with a mode sensitive filter configured by joining an optical fiber or optical waveguide having a single transmission mode at a long wavelength (1.2-1.7 mum) and an optical fiber or optical waveguide having a single transmission mode at a short wavelength (0.6-1.0 mum). With this construction, the optical transmitter / receiver can remove high-order modes generated when transmitting light having a short wavelength along optical fibers having a single transmission mode in the long wavelength range. Accordingly, it is possible to perform broadband transmissions using an inexpensive, short wavelength optical transmitter / receiver.

Description

technical field [0001] The present invention relates to an optical transmitter and receiver, and a mode sensitive filter therefor. Background technique [0002] Optical fibers known as single-mode optical fibers are widely used in the prior art. In a broad sense, single-mode fiber is a general term for an optical fiber that supports only one transmission mode at a time, and more specifically, a single-mode fiber is an optical fiber that supports a single transmission mode at a wavelength of 1.2 μm or greater. The latter defines single-mode fibers generally with a core diameter of about 10 μm. [0003] It is well known in the art that, for example, when attempting to transmit light at a wavelength of 0.78 μm along a single-mode fiber of this type, multiple transmission modes will result. Figure 4 is an explanatory view showing this process. In an optical fiber with a core diameter Da of 10 μm, light with a wavelength λa of 1.3 μm propagates in a sin...

AI Technical Summary

Problems solved by technology

However, a large number of single-mode fibers (fibers having a single transmission mode in the above-mentioned long-wavelength region) already exist, which presents difficulties in laying new fibers with different core diameters

Images